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MG MGF Technical - Trophy throttle body shock!
|Just returned from the Emerald rolling road. Must say thanks again to Dave Livingstone for putting this day together, and to Dave Walker at the RR for all his hard work (and for the girls for feeding and watering us!)|
A fantastic day! If you missed it, Dave'll be organising another for early next year :o) Great to see everyone again before the Christmas break to :o) Alot of happy faces, and laughs had by all.
Also very useful for some of us to identify potential problems, and for us to look into the pros and cons of the almost legendary Trophy 52 mm throttle body on the 1.8i.
From Roger Parker's previous experience, we know that the TTB is good for about 5 bhp on the VVC (as installed in the Rover 200/25 MG ZR engine bay, in conjunction with the ITG Maxogen air filter).
But any good on the MGF 1.8i? After all, we know that K&N 57i kits release more power on the VVC than it does on the 1.8i... So what can we expect from the throttle body on the MPi engine?
I got 129 bhp @ flywheel with the 48 mm standard plastic throttle body. (My car has a Mike Satur exhaust, with a 57i K&N airfilter enclosed in the R820 airbox)
Swapped over to the alloy 52 mm throttle body under the glare of the MGW cameras, and repeated the run.
How much peak power now?
Yup, you got it, 130 versus 129. On the standard 1.8i engine, this throttle body represents no gain whatsoever over the standard TB. I haven't got the torque figures here, but it was noticeable that the before and after curves are practically identical, with a *few* areas where the TTB was fractionally better.
On this basis worth the money? No. Absolutely not.
Driving impressions? Well, throttle response was massively better on the drive home from Brixton. But the explanation for this is not improved power or torque, but a virtue that for any given throttle position, because the throttle choke is that much larger, more air will be flowing - and is therefore equivalent to a larger throttle opening on the original TB. A similar effect could be achieved just by altering the profile of the butterfly cam. :o( It felt great though, funnily enough, so I understand why people rave about them even though they aren't any good at increasing absolute power.
Why is there a difference between the 1.8 and the VVC? Because the standard throttle only starts being restrictive at outputs greater that 150 bhp. MGR knew this ofcourse, and hence the installation of the 52mm TB on the Trophy 160.
So, sorry folks. For all those with non-VVC or head/cam modified cars, don't bother with the TTB - spend that 100+ quid on something that will achieve something (like put it towards MTBs or a nice Piper cam.... ;o))
Plenty of other revelations like this today - I'm looking forward to pouring over the data when that becomes available through David Andrews.
All I'll say is that Dave Livingstone was a happy (and relieved?) bunny! LOL
sorry, missed this date ;)
Glad to see you all had great fun.
>On this basis worth the money? No. Absolutely not.
LOL, that's why I spent only 10 quid for the second hand Vauxhall thingy (DIY hours not calculated) ;)
Anyway, don't forget the metal body is worth to get, cause the danger of a sticking butterfly disappears.
Almost better to replace the old plastic crap with the TTB then suffering from that sticky troubles.
btw had anyone installed the PBV ?
I had a PBV, but I'm afraid it stayed in it's box in my boot. I would have liked to do a before and after RR run with it, but I chickened out when I read the installation instructions. I just didn't feel competent enough - sorry! However, Dave Walker wasn't very encouraging about its potential to make a difference. Nevertheless, now that I have it, I will get it fitted and go back to DW's RR for another run - just to see if it adds anything.
Here's the peak results I got without it:
172 bhp at 6500revs (flywheel measurement)
138 ft lbs at 3,800 revs
This is a VVC with ITG Maxogen, 52mm Throttle body, Phoenix exhaust and a fully ported cyclinder head by K-series guru Dave Andrews.
Very pleased :-)
Full data still to come once the graphs have been produced.
|Please guys - can you quote the actual measured at the wheels figures, not some fudged-up quasi- scientific guesstimated factored flywheel figure ?|
>I chickened out when I read the installation instructions.
Not a five minutes job, of course.
http://www.mgfcar.de/mgfcar.de/power_boost_valve/ (no description)
this test will be very interesting indeed when all data are gathered BUT IMO one can NOT make a swap with ANY bolt-on eq. and say it is an A - B test!
This simply because there is a need for several start-stop cycles for the total MEMS system until it fully adapts to the new situation. This is all too obvious when one makes an exthaust test with a SEPARATE lambda sensor placed in the cat-bypass tube ! I was puzzled for some time when doing the "poor mans FSE" by just momentarly closing the returnpipe from the fuelpressure sensor with a 12 Volt solenoid valve and using the existing labda sensor with an attached readout. It seemed that whenever I gave full throttle the value went to "Rich" or slightly above without using the solenoid. BUT THIS WAS A FALSE READING as the MEMS inserted a pre-set voltage that wasn´t from the actual sensor reading !! Only by using a separate lambda sensor I got the true reading and could find out that the adaption-time for the MEMS is indeed several start/stop cycles OR a prolonged drive during different loads.Actually I was running lean until the extra fuel was delivered by closing the solenoid ! So here we cant see any immediate changes for GOOD or BAD when doing quick changes of exthaust / throttlebodies/ filters etc. Pictures on my installation will be sent to Dieter when time permits (probably free days around Christmas/New Year:)
|Thanks for this thread Rob..... I was making the phonecall tomorrow morning to get myself the TTB.... PHEW !!!!.... a lucky escape ;-)|
Ok, so MEMS will bung in default values when it thinks a sensor is "faulty"... but how much will the MEMS systems "learn". ie. Will allowing a mod to 'bed in' make a huge amount of difference - if any?
I can see how submaps will tweak the 2D map, but who knows how it works wrt any learning capabilities?
A really interseting result, but I do support Carl in that when I fitted a TTB to my VVC there was an immediatly noticeable difference, but the improvement did seem to increase as I drove the car more - at the time I put this down to mems adapting to the new TB, so maybe you would have got an extra 2bhp if mems had had time to fully adapt!.
|Yes, I would much prefer the rear wheel horse power than a silly fly wheel figures :-)|
What was yours Rob? :-)
And Also David's one would be interesting!
I witnessed it and completely agree with what you have said.
I do not think, as has been suggested that this lack of performance was due to engine management issues and MEMS not being given the chance to learn the new component values.
The only thing that MEMS would learn is the potentiometer characteristics on the new body. Which would be nigh on the same as the ones already in it's memory as there is no adjustment on these throttle pots.
As you probably know, MEMS sends a voltage into the POT and depending on where the throttle and therefore the POT is, a different value goes back as an input. At idle, a low value - I think around 0.325 VOLTS and at full throttle a higher value. As you open the throttle, the voltage MEMS receives back rises with throttle opening and it therfore determines throttle angle.
There would not be much difference between the two components, so MEMS would not have much to learn anyway, after a few miles MEMS would potentially alter it's settings very slightly but this would mainly affect low throttle openings and potentially idle.
MEMS uses speed/density to calculate fuelling, the most critical input being MAP or manifold absolute pressure. When the car was on the Rolling Road at full throttle, the MAP sensor would tell the ECU that the Manifold Absolute Pressure was 1 atmosphere - no vacuum.
ECU would assume full throttle programme - fuelling and ignition and engine would attempt to develop full power - as it did +1 BHP.
You are correct and it did not produce more power simply because your engine does not suck in enough air at the moment for it to be an issue. Interesting how throttle response improved, but as you say this is due to the larger area and also the thinner butterfly which will pose much less of a restriction, particularly at low throttle openings and therfore let through more air - just equivalant to pressing throttle down further with plastic body.
If we read what Rob said carefully... there is as good as no performance increase but the driving feel was "massivly better". But is it worth £100+ on a 1.8i? Probably not.
I've read up a bit on the MEMS and I cannot see how it can be described as properly "adaptive" - yet. As far as I can tell it's adaptive capabilities compose of a series of submaps that will 'tweak' the main map depending on certain other inputs.
From Carl's comments I'm presuming that there is some form of averaging that will slew these changes over time. Is this what we call 'adaptive' ?
|There is a reason why power at fly is being quoted and not at the wheels but let me defer to one of the other guys to explain.... Rob, Dave, Paul.....|
as I dont have any experience of the 1,8i - only the vvc there might be a diff. in behavour. One thing is for sure, any alteration needs driving time or several start sessions to be fully adopted.
Regarding the throttle pot : The changing voltages on the pot (around 0,3 to 5,0 Volts) are only used to determine if any extra pulses are needed on the injectors. Slow opening of the throttle = no extra fuel, fast opening = more open time on the injectors + more pulses. This can be seen on "Test-Book" computer when the engine is in dynamic (running) mode as the individual injector times are displayen in graphic mode as well as tabular.
I'm talking of the VVC MEMS as well. I believe the MPi is the same.
What alterations could be done by MEMS over a number of engine starts? Surely MEMS takes reading from the main sensors and looks it up in a 2D map... then it will apply 'corrections' found from other maps depending on other sensors (eg. Water temp). What I don't understand is how this can be seen as "adaptive".
I can see that a few engine restarts may make a difference though if the auxilliary lookup deltas were averaged over time - which would seem sensible as you wouldn't want one spurious reading to result in a dramatic change in the engine.
Fundementally the engine can only 'adapt' if any of the sensor readings are changed because of any alterations made. Would sensor inputs like the MAP sensor and the Air Temp sensor change after the fitting of the throttle body?
I'm not disagreeing with you Carl. I want to understand some of the complexities of the MEMS.
Any recommendations for reading on MEMS?
|There are good reasons why Dave Walker provided us only with estimated flywheel figures (calculated, as at other R&D RRs using a negative run-down to calculate transmission losses).|
I'm not going to go into the whys and therefores here ;o) For my purposes, I was primarily interested in the delta change values ;o) but the accuracy of the figures from this road are excellent, reproducible, and David has an excellent (and deserved) reputation at Emerald.
I completely concur with what you've said Matt - these are max-throttle opening runs on the RR - therefore the Throttle position sensor will be reading the same figure on both the old and the new TBs. As you say, under these circumstances the MAP sensor dictates how MEMS responds - therefore there will be no need for MEMS compensation to realise the difference between old and new.
Carl, I agree, the MEMS did take a while to get a hang of part throttle openings - the engine had an attack of the 'skippy the kangaroo' on the way to Elephant and Castle - but by the time I reached home that night, all had settled down. And this was despite having reset the throttle position sensor prior to the power runs (car on an even, normal, warm idle speed). But this compensation does not necessarily mean more peak power or torque. Another observation: when we've put together back to back comparisons (similar in construction to the tests we performed yesterday) of air filters and exhausts, we HAVE seen significant differences: up to 5 bhp with exhaust systems and 8 bhp with filters (both on 1.8i cars). Moreover, this change of power has NOT changed when the same car and filter/exhaust combination has been checked months or even years later. So I am confident that the results hold. This 52mm throttle body is pointless on more-or-less standard 1.8is (but as Dave Walker said, it is a good platform for other mods at a later date). The 1 bhp change is probably within the measurement standard error.
Others got much better results than I: on the ZS180, they had fitted a Rover820 airbox in place of the standard restrictive affair. Result was a peak power recording of 191 bhp...! Very impressive! :o)
|I think we should have learnt this years ago when we were a lot younger, and poorer, fitting larger or multi carbs on to a near standard car, didn't make it go any better but it looked good.|
You have to do all the other things as well, head work,cams, exauhst etc.
Although some of the problems of sticking, poor operation of throttles on the plastic TB's it may be worth the cost and effort after all.
So therefore the the learning would not affect absolute power - when the throttle was jammed to the floor for 30 seconds from 1500 - 7000 ish RPM.
In my opinion:
If you have a non VVC K, not heavily modified to produce power circa 140BHP - cams, ported head etc, do not bother buying the throttle body as you will be wasting your time and money.
|>>Why is there a difference between the 1.8 and the VVC? Because the standard throttle only starts being restrictive at outputs greater that 150 bhp. MGR knew this ofcourse, and hence the installation of the 52mm TB on the Trophy 160.<<|
The difference is more a question of breathing and not horsepower, I think. The breathing only becames an issue at higher revs. As the VVC is more revvy than a MPI you need a proper TB.
Thanks for the report, ROB.
172 bhp at 6500revs (flywheel measurement)
138 ft lbs at 3,800 revs
This is a VVC with ITG Maxogen, 52mm Throttle body, Phoenix exhaust and a fully ported cyclinder head by K-series guru Dave Andrews.
Very pleased :-
I would be too! Good results!
see HGF can have it's upsides ;)
|I presume the full results of the day will be published soon, but did anybody test a relatively standard VVC with say only a TTB, K&N and maybe sports exhaust?|
|Yeah, there were a couple of them.|
I am sure someone will post what they made but it was impressive and over what was expected. High 150's I think.
|Sorry tho bother you guys again with this:|
the 120BHP claimed by MGR for the MPI is @ fly wheel is it?
If so, results on the VVC by Dave Andrews conversion is quite astonishing and hence very interesting.
Thanks for the report,
I'm no expert on any of this - just learning stuff through MGF ownership and having fun doing it. However, I value enthusiasm and experience and Dave Walker at Emerald has both in spades - as has Dave Andrews. Both have extensive K series tuning expertise whcih translates directly from the Elise and Caterham world, that they are well known in, to ours.
The measurement of bhp and torque was at the flywheel. This was done with a RAM12 rolling road. I captured Dave Walker's views on this on a tape recorder, which I have very roughly transcribed here. No, I don't always carry a tape recorder around in conversations! I'm going to write up an article for MG World and have a lousy memory. Plus, as I said, I'm no expert - just a keen F owner.
Here are Dave's thoughts on Rolling Roads - apologies for the length - I could have precised it, but I should be working!!
· Key feature is the operator – have to play with it and find out how it works – was always measuring power at the wheels – used to quote power at the wheels in mags because didn’t know what was measuring. After played with RR and figured out results – worked out that power at the wheels is total nonsense – anyone who quotes it doesn’t understand how it works – you have to measure the run-down losses – power at the wheels is OK for setting up – you’re looking at the dial – if you make some adjustments and it goes up 5 bhp – it goes up 5 bhp – but that doesn’t relate to the flywheel – you have to correct for barometer and temperature – get differences summer and winter – have run RR sessions for the same car at different times of year and got the same result
· Do you do a negative power run to figure out transmission losses for example – no not a run – you run it up – knock it out of gear – as it’s running down it’s pressing on the load cell in the other direction and it just measures the loss – people say RR not accurate – usually it’s the operator.
· Example – if I give you a ruler and you don’t know how to use a ruler then you’ll measure badly.
· Other argument – it doesn’t matter if you use the same rolling road – if I go to buy a ruler – I don’t want a 12” ruler that’s 30” long – on the grounds that it is the only one I’m using – it’s a measurement and you want it to be right – so messed around with RR until got the right results – e.g. as seen today - got within a bhp of the right result for a standard car. The RR is just a tool.
I hope this helps. I'm obviously more than pleased with the work Dave Andrews did on my cylinder head after my HGF. The range of Fs (and Zs) at the RR yesterday, provided a great comparative base and once we have the full curves, I'm sure will spur even greater debate.
The sort of discussion that began with this thread, on the adaptability of the MEMS, is great - let's keep sharing our experiences. I've learnt lots from this BBS over the years. People like Carl, Dieter etc. who I can't get to meet - people like Rob, Paul N, etc, who I've met on and off track at various events. All share the same enthusiasm and have a great deal to offer. Let's keep the discussion going.
indeed a very impressive work done by all involved - a big Thank You !
As Dave mentions this will come as a report in "MG World" (awaited and recived here every bi-month ! )My guessing is that there will probably be too much data avaible to tell it all in the comming article ? So if possible it would be of great interest if there was an internet site where "left-over" from the full test could be read at time of publication or slightly after ? I think this could be possible for other good articles like the K-engine job etc. Of course it involves more work but especially this rolling road test would be very interesting to read in full...
During the Christmas /New Year-break I will have the opportunity to play with a "Test-Book" unit and enter deep into the "Tool-box" section. Deep down there are several selectable maps for the VVC and maybee also for the 1,8i. They are just a password away ;) But one has to be careful, there is also a "Format C"-command for the ECM and anti-theft unit that is very scary..
|>>My guessing is that there will probably be too much data avaible to tell it all in the comming article ? So if possible it would be of great interest if there was an internet site where "left-over" from the full test could be read at time of publication or slightly after ?<<|
Carl, if David is agreeable then I'll happily post to my website any unpublished data (the actual RR curves, as per previous filter and exhaust tests).
When the data becomes available, there will be some very interesting data pertaining to the latest generation of filter kits, including the K&N 820 mod, the flower pot mod, the Pipercross Viper and the ITG Maxogen on a mix of models... :o)
Great ideas. As soon as all the data is to hand and I've distributed it to the participants, I'll ask them all for their permission to make it public. Obviously I don't mean make the owner's names and car registrations public - we'd automatically remove these! No, I mean the actual data and graphs. As they paid for the RR to produce the data, they 'own' it and so I think it's fair enough to ask for their permission to publish it, both in summary form in MG World and in full on any website afterwards, don't you?
|Some short comments. |
When I did the back to back tests between 48 and 52mm throttle bodies on the modified VVC it was done on DW's rolling road and the test sequence was done twice, with several runs at each time to verify readings, which showed that consistant 5 bhp difference. Please also be aware that there was no gain showing at all below 5000rpm and this tells as much of a story as the 5 bhp. Clearly as Valter has already noted this is not an issue directly related to HP, but is one also related to rpm and the engines ability to breathe efficiently at the higher rpms and the faster gas speeds involved.
This is why you also see the 52mm body used on the TF 135 spec engine, even though this is well below the 150hp dicusion level. Here the extra power of the 135 eminates from the use of different cams which now move the power peak to 6750rpm from the original MPi's 5500rpm. Here it is the airflow perfromance at the higher rpms that is actually providing the need for the larger throttle body and in turn providing one small beneficial aspect. The nature of airflow, swirl, squish and combustion are seriously compklicated and changes in one apparwently unrelated area can have some interesting knock on effects.
Now another aspect to consider is what happens if you modify a throttle body to provide a significantly increased maximum potebntial airflow? Having now started along this road and got such a modified 48mm throttle body that is able to match and in some areas out perform a 52mm body you would perhaps thing that this may offer similar benefits to a 52mm body, as doing the same sort of flow work on carbs offers that sort of improvement. (Subject of course to not affecting the function of a carb to pick up and distribute fuel properly.) Well initial results show not changes so at this stage you could then point to the fact that the enlarged throttle area is the key and not the flow potential. Unfortunately there needs to be some more tests before that can be confirmed. Interesting nevertheless.
Dave, your VVC output is very close to that of the VVC engine I have used, which with the very similar basic specs is perhaps not a surprise. Of note is that the actual reading you will have seen at the wheels will have been between 136 and 140bhp. This in fact is a greater variation that the resulting 'corrected' readings that DW is able to produce.
At the end of the day the RR is a very useful tool to enable the operation of an engine under varying load conditions whilst sitting in the vehicle chassis. During this time it is possible to measure a wide range of functions and from this optimise the efficient running of that engine, whether the engine is in an original specification or featuring modifications. Looking beyond this to compare readings can be as accurate as most petrol station forcourt tyre pressure gauges!!
The PBV is an interesting and an area which again I have been working on recently. Note that the standard MEMS system operates with a nominal 3 bar fuel pressure. In fact the system caters for production tolerance with an acceptable base range of pressures that run between 2.8 and 3.2 bar. Here the adaptive nature of the system when operating in closed loop, which it is not when operating at full throttle, compensates through lambda input where there is variation from the nominal 3.0 bar spec.
A well known tuning and vehicle preparation company whom I deal with has created a rig which tests and allows adjustment of the standard pressure regs, so I have had one set to 3.2bar. Before modification it was set at 2.95bar. In closed loop operation the engine will be easily capable of staying within designed emission levels, but in open loop where injector open time is fixed depending on the base line map settings for whatever load and rpm we are at, the increased pressure will equate to approx 5% more fuel flow.
On the VVC engine this has had a very positive effect in throttle response and general driveability and although no back to back rolling road test has been done I suspect the difference will be quite small. Bear in mind that this engine is operating at near as 100 bhp per litre with otherwise standard (145ps)VVC mapping, which is said by those who have more experience than anyone else with the K series development to be very close to the maximum limit beyond which the engine will be running lean and risk holed pistons. The effects of the regulator change indicates to me that this is so, even though a separate lambda set in the exhaust was still showing an ideal slightly richer than 14.7 to 1 air/fuel ratio, before the regulator change.
One thing is certain and that is beyond around the 170 to 180 bhp mark on the K series and further gains are all about trading power for torque. Fine for a light weight fun car like Elise or Caterham, but something that any heavier steel bodied car like MGF and Z Saloons will then suffer more negatives than gains. Rob's airbox mod shows a very important torque gain and that is what gives far more on a road car than top end power so keep focussed.
As a final aside the old Maxogen from my F has been hijacked by young son for his 8 valve MPi Rover 100GTa. Apart from being relatively simple to fit compared to the F or a 200/25/ZR it works far better than in the F and has given a whopping increase in mid range torque. Anyone with wife/girlfriends etc second cars being similar may want to try this or the R 820 airbox trick. A mate of his was disgusted at the improvement in the mid range as it is actually quicker than his 1.8 Metro. Torque always talks!!!
Sorry I couldn't get down.
|Great description there, Rog.|
I think you mentioned some important issues.
Totally agree. Valter
|Rog, Valter - I believe that you are both right - I guess I was using power as a surrogate for flow, as the two are related in terms of engine volumetric efficiency.|
And volumetric efficiency might be key here, bearing in mind that there is another obvious difference between VVC and TF135 engines and the 'normal' MPi other than cams and head design - that being the inlet plenum.
Obviously I have a bog-standard plastic manifold on my car. It's been demonstrated, I believe, that the plastic manifold promotes low-end torque at the expense of high-end power. The alloy VVC plenum being the opposite. Given that all the power liberated by the 52mm throttle is top end, it may stand to reason that the standard plastic plenum represents a restriction to airflow, and thus negates the potential advantages of the 52mm TB?
Therefore, there MAY be a benefit to fitting a 52mm TB to a 1.8i - but to see it you MUST also have fitted a high-flow airfilter arrangement and a suitable high-flow inlet plenum.
Anyone got a car with a standard 1.8i head and a maxogen airfilter and VVC-style plenum? That used to be Andy "SF" Phillips - but Mike recently ported the head for him... D'oh!
|Great work guys,|
I'd be interested to hear more on the 820 box mod on a standard VVC. Also surprised to learn that there wasn't any real improvement on a standard 1.8 with the 52mm TB though.
|IMO the 52mm TB isn't a waste of money. It definatly improves the car (MPi), although it may not be visible in the charts. Maybe it just adds a bit of more fun to the car when accelerating flat out.|
BTW, the SP does scream a bit less with the 52mm
|>>the standard plastic plenum represents a restriction to airflow, and thus negates the potential advantages of the 52mm TB?|
Therefore, there MAY be a benefit to fitting a 52mm TB to a 1.8i - but to see it you MUST also have fitted a high-flow airfilter arrangement and a suitable high-flow inlet plenum.<<
Yes, you are very probably right, Rob. That is the issue, here.
|>>> ... and a suitable high-flow inlet plenum. <<<|
Like the one that is sold by PTP ltd. as
VVC Style Inlet Manifold kit
or am I just talking nonsense ?
|>>Like the one that is sold by PTP ltd. as VVC Style Inlet Manifold kit<<|
Yes, that's the one Erik. :o)
>>I'd be interested to hear more on the 820 box mod on a standard VVC.<<
Yes, that would be great to see, I agree Leigh. Has anyone completed this conversion on a VVC yet?
Looking forward to the next Emerald RR session already! LOL
if thats your short comments can't wait to read the full article.:-)
Good work all round, very informative but, whats the difference between torque, bhp, flywheel etc can anyone translate into i just about know where to petrol kind of guy talk
Have a read of http://members.aol.com/emeraldm3d/ which tells you how a Rolling road works.
Very good explaination.
have my homework for the night now ;-p
|Still a bit in a shock, but euh... what about fitting the kit with multiple throttle bodies?|
Is this usefull if the head isn't been reworked (yet) ?
If so, getting a proper inlet manifold could do some (!) magic to the TTB.
Exactly Erik !!!
So that my project for the early part of the new year on my VVC, Emerald system with Multiple throttle bodies and all the reworking that goes with it !!
I have already discussed it with Emerald and will be talking to Techspeed put together a costing to mastermind the project for me.
I hope the cost is not too preventative !!
|>>Still a bit in a shock, but euh... what about fitting the kit with multiple throttle bodies?|
Is this usefull if the head isn't been reworked (yet) ?
If so, getting a proper inlet manifold could do some (!) magic to the TTB. <<
Erik, yeah I agree - there are some issues here that need to be more completely investigated. Dave Livingstone (DL - far too many Dave's around!) asked Dave Walker (DW) what his prefered route of tuning would be. I seem to recall that DW said that he'd go for a set of Jenvey direct to head TBs, in conjunction with his Emerald M3D engine management. He'd then go for a pair of Piper 285H cams. The implication here is that head porting, whilst hugely beneficial, need not be the first port of call in getting serious power from your K-series. Moreover, there was an implication, in the way that the answer was phrased, that MTBs may give a decent improvement in peak power and delivery independently of other work - which is very interesting.
I'd love to see that data!
Stu - good for you mate! I know that DW is just itching to have a go at an MGF, and to play around with a VVC in particular! Should make for a very exciting car - I'm going to go BRG with envy! LOL
Might I recommend sir consider some bigger brakes all round? Suits you, sir.
|Just a thought but Mike advertises almost VVC power gains from the 1.8 MPi when the 52mm is fitted with a Viper induction kit.|
|Hmm, I didn't use the Viper induction kit for this test Chris, so Mike may well be right (see discussion above). Something else to try when we head back to Emerald in the new year.|
|Anyone tried either Rob's K&N enclosure or tried using a Rover 820 filter rather than the standard filter and piping arrangement? I may take a look at this in the new year...|
|>>>if thats your short comments can't wait to read the full article.:-)<<<|
My middle name is Tolstoy! :-)
The reasons Dave Livingstone went for head porting rather than TBs or other mods were simple
i) changing to TBs would be too much for the stock ECU and there is currently no after-market ECU that will handle the VVC mechanism
ii) the head was already off
iii) he wanted to retain the VVC mechs
I tried to persuade him to go for a hotter exhaust cam which I believe would bring more torque.
TBs definitely give an improvement in midrange and top end power both on the VVC and MPi, I do a range of kits which include the M3D and TBs together with cam changes which give very good results without disturbing the head. However cam choice is limited due to the restrictions of the stock valve springs. Fitting BP285H cams cannot be done without lifting the head and replacing the valve springs since the lift they give will coil-bind the springs. That said they are a very capable cam that can give outputs up to 200BHP from both the MPi and VVC given the right complementary mods.
I have a kit available that gives 190BHP on the VVC engine which includes TBs, an M3D and appropriate solid cams and conversion kit. As soon as Karl at Emerald has VVC control working in the M3D then the options are wider for VVC engines and I will be working with Dave W to develop a kit which retains the VCC control but allows TBs and other mods.
This thread was discussed between 08/12/2002 and 26/12/2002
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