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MG MGF Technical - Chipping & Exhaust

1. Has anyone chipped an MGF 1.8i and is it worth it - can you recommend one and how much cash

2. Exhaust - is there a decent replacement exhaust out there giving noise and performance at a decent price?

3. An whilst I'm here 3rd party leather interior can anyone recommend someone?
Tim

K&Ndunno really, but heard potentially bad things

2. Exhaust - quite a choice all around
Matt

Matt, the next update is nearly due, and will include the power graphs for each of the exhaust systems tested.

So as not to keep you in too much suspense no exhaust liberates more than 5 bhp on the 1.8i :o( Therefore from the pure performance point of view, they do not represent particularly good value. But then if you factor in a more characterful noise, looks, stainless steel construction, you may find that the balance favours a system- but that is up to you. The best we measured was the Mike Satur Daytona system, followed by the Miltek Supersports and then the Trevor Taylor Fxtreme.

A better option, performance wise, is a replacement air filter. These figures are on my website (http://go.to/mgfgallery)- the best filter option at that time was the K&N 57i. ITG have now brought out a new filter box assembly that could well prove even better, but I haven't tested it yet, and it is considerably more expensive:o(

Engine management systems- there is a tricky one. If you have one fitted, then you MUST have it properly programmed by the manufacturer. Folks who have fitted Superchip's product straight from the box have had their engine go pop in worryingly short order. A better bet is the programmable replacement ECU which alters both fuelling and ignition. IMO this option need only be considered if you are going to radically alter the inlet/fueling system (eg. throttle bodies) otherwise, you'll find that the standard MEMS will cope admirably well.

The route to real power on the 1.8i engine, from what I can gather, is through gas-flowing and porting the head which is a real limitation on the 1.8i as it actually shares its head and valve dimentions with the 1.4 and 1.6 engines. Bigger valves will liberate more power (not too big, or bottom end torque will be sacrificed- VVC size seem to be about right). Others have fitted a slightly higher lift cam shaft (Piper sell a range of these) with a 'sportier' timing. Well worth considering.

So the questions are:
1. How much do you wish to spend
2. How much of an insurance headache are you willing to put up with
3. How 'reversible' a conversion do you want (modified cars are very difficult to sell on)
4. What kind of performance gain are you after?

Rob
Rob Bell

Tim,

Unless you have a heavily modified engine then it's not much point fitting an different ECU.

However I've fitted a device from a company called Racelogic called a VSAM unit, around 200 (similar to the Superchips ICON unit). It's very easy to fit, literally 5 mins and gives the engine a modified ignition map. It advances the timing slightly to release more power. Apparently the standard map is designed to work with very low grade fuel. If you use normal unleaded petrol from Western Europe the engine will run fine. Used in conjunction with a K & N type induction kit Racelogic claim around a 13-15hp improvement. This I confirmed with my own test on a rolling road. Also it improves throttle response and driveability. I've also found that peak power is around 7000rpm now, up from the standard figure of around 5500rpm.

I've also fitted a Miltek Supersports exhaust (300). This looks and sounds great but only seems to give a few extra hp despite some of the manufactures claims. Finally a word of warning re. the K & N induction kit. There is a lot of hype regarding the improvements. From my own experience of fitting this to my 1.8i car I found that before I fitted the VSAM the K & N spoilt the response/pickup of the engine at low speeds - this included 70mph in 5th gear on the motorway. All I got was loads of induction noise and not much action. Yes you will get a improvement in overall power and once the engine is spinning around 4500rpm the response is better than standard; the sound is great too. With the revised igintion map however there are no such problems and the engine revs more freely and noticeably delivers more power throughout the rev range.

Darren

Darren, no hype. The results for the K&N (8bhp on the 1.8i and 15 bhp on the VVC) were exactly as a group of us from this this very BBS found when we tested the K&N against its competitors. In fact, JT has also verified the 8 bhp power gian on his own 1.8i with the K&N independently of us, so we can be reasonably confident of this value.

No sure why you failed to find the gain yourself- but there are a number of possibilities which may or may not apply to your case. The most likely revolves the the need for cold air: if the cold air ducts are not fitted, not fitted properly or have fallen out of the airstream for what ever reason, then all the power gain associated from fitting a K&N filter is lost: the filter is mounted in an area of the engine bay that can reach over 50 degrees celcius, so an outside air supply is absolutely vital for maintaining inlet air density.

I agree with you regarding the exhaust system- SP's (Miltek) claims for additional power are worrying overstated in our experience. 3 bhp is the maximum we saw with this exhaust system on the 1.8i. Nicely made and sounds great though.

Rob
Rob Bell

Rob,

Yes the kit was fitted OK, including the cold air ducts.

I'm not disputing the overall power gain. I got somthing similar, but it spoilt the low-mid speed pickup. This was noticeable compared with the original standard engine.
Darren

Hmm- that lack of mid-range pick-up is interesting. There is a 'dip' in the torque curve on 1.8i engines that occurs at around 3,500 rpm on standard engines. The K&N filter appears to exacerbate this, and pushes the 'dip' a little further up the rev range. This may be what you've noticed, but am surprised at the degree to which you've found it- maybe I am over staing your obserations? Anyway, I got sufficiently annoyed with the 57i kit on my own 1.8i to try alternative filter mounting positions and found that by mounting the filter directly to the throttle body removed this 'feature' making the car nicer (more responsive) to drive around town. The downside was that the top-end power was lost- and that was something I happen to need for Hillclimbs etc.
Because I had access to the power curves from both filter and exhaust tests (handy eh? ;o), I noticed that the torque peak from the Trevor Taylor exhaust overlaps the torque dip of the 57i K&N- so now I have the K&N as originally intended and one of Trevor's finest exhausts and the combination works very nicely indeed!

Do you suppose that the Racelogic ECU you have fitted may be exagerating this characteristic Darren?

Rob
Rob Bell

Rob,

No, it removed the problem. I only experienced it before I fitted the Racelogic unit. I saw your power curves and suspected that the 'dip' was what I was suffering. The K & N was fitted with the SP exhaust though. Maybe this made it worse??
Darren

Wow- that's interesting. That the Racelogic chip removes the problem suggests one of two things to me: 1. the torque dip is a function of the standard engine management map or 2. the Racelogic chip has an algorhythm that compensates better for it.

Can anyone shed any light on this? My thoughts are that the torque dip is a feature of the induction tract and cylinder head.

Darren- it is entirely possibel that the SP could have made the K&N related dip worse...

Maybe we should work out what products match and which do not?

Rob
Rob Bell

I am no expert and certainly have not done any rolling road tests but I have found that on my MPi K&N works extremely well - however to smooth out the loss a little I tried (like Rob) different spacer tube lengths and in fact I am running with exactly half the supplied length.

I must stress this is for MPi (not VVC) and I am no expert.

Ted
Ted Newman

Seems I am not alone in the quest for power! I have fitted the K@N57i to my 1.8i and enjoyed the racier tones rather than the slight power gain. It was only until I fitted a power boost valve(from Moss)that the car has took on a new light.I can really feel the gains in power. Downside is the loss of MPG though thats not helped by my new found enthusiasm to put 'pedal to metal'.
Rob Marsh

Interesting feedback by individual owners that really confirms one fact, that being that each engine is an individual and whilst general assumptions can be made for the effect of a particular devise or action, it will not guarantee that all engines will respond in the same way.

The dip in the torque is something that I don't have on my engine with the rerouted air induction system that Rob is aware of. I also gained an additional 9ft lbs in direct comparison to both Robs and another new F at the time we did the exhaust tests. 12 degrees C was also the average reduction in my intake air temp. I have yet to confirm or otherwise whether this temp reduction is carried over into the normal on road driving excperience. (The testing to date involves ony rolling road tests - numerous.)

I also note with considerable interest the results Rob M has seen with the addition of the FSE. Some may recall my observations on how a 1.4 Metro MPi with just a cone filter and FSE was producing within 4 bhp the power of an average 1.8. The engine was clearly very much more responsive and powerful in normal driving.

Looking a bit deeper it should always be remembered that fuelling is controlled by the injector being opened for a given time as dictated by the ECU. This injector open time relies on a constant, this constant being the fact that fuel pressure is maintained at a known value above the pressure that is found within the inlet manifold. It is mostly unknown that the mechanical operation of the standard fuel pressure regulator has a degree of acceptable float in terms of its operating pressure. Something around 0.4bar float.

Now it doesn't take a genius to realise that a car with a regulator at the low end of the scale will allow the engine to operate with a weaker mixture and as whilst the engine may not actually suffer from this it is likely to feel lethargic. Oddly there is often not a great deal of power variation, torque though can suffer.

The addition of a very much less restrictive air filter acn upset things and see a more pornounced change. In these cases the engine is at times dropping beyond the fuel mixture range needed for clean running. Adding fuel pressure, and by definition richening the mixture for ALL operating conditions will at a stroke correct this problem and at the same time move the fuelling to a richer platform. In doing so not only is the loss from weakness regained, but additional torque and response achieved. Add this to a free flow airfliter and now the additional airflow has additional fuel added to it so more power and torque is achieved.

I normally do not like the idea of jacking up fuel pressure, but the FSE has the distinct advantage of operating with a rising rate so that much of the time in normal driving there is little change in pressure so excess fuel is not poured down the exhaust.

The same applies to the ignition map, but where the engine is running to expectation to start with the gains are much less. There is indeed some measure of conservatism in the mapping settings, for the reasons stated and others of engine longevity. (I remember one conversation at the Lucas test and development labs where I was asking about the settings they had done for a number of Rover engines and the reply was, 'Yes there is more power available, but how soon would you like the engine to go pop?')

Clearly some advancement of the spark timing can add to the combustion effects for a given area of engine operation. If the engine is running a very weak mixture then the mixture is far less combustable and will benefit from a greater time in achieving maximum burn, and maximum pressure rise. This could well be of advantage where a K&N is fitted and could really show dividends.

However if the mixture was to be richened from that state then the need for extra advance is often negated and so with extra advance maximum pressure is achieved much earlier and this then acts against the movement of the piston, putting considerable strain on the engine. In severe situations this is detonation, but it is this inaudible mediuum state condition that is potentially the most damaging.

I do have to say that I am surprised at the lack of apparent interest into alternative engine managment controls. Forget messing with piggy back this and that, and go for a programmable alternative ECU. Take Luminition as but one example. They have plug compatible programmable ECU's available for the MPi engines (not yet VVC, but they are actually looking into that area at this time.) Numerous of the specialist car makers conversions use different engine managment control, and Lotus have recently seen fit to follow the same route.

I have been talking in detail with several companies with a view to this route to match the spec of my engine once the modded head is fitted. However this is partly due to being drawn to the multiple throttle body conversions and the benefits thsi offers in pure volumetric efficiency over a single standard common size throttle.

Rog
Roger Parker

The characteristic K-series torque dip at 3000-4000rpm (depending on capacity & state of tune) is largely down to the exhaust manifold. The standard 4-1 is quite nasty, and has a much bigger effect on engine output than the usualy bits that are peddled with power increases on the label (silencers and tailpipes). A good 4-2-1 will have big effect on the midrange performance but will probably require a remap to get the best out of it.

Note that changing one component usually has a knock-on effect elsewhere, so freeing up the induction will affect what the exhaust does, hence the K&N filter swap affects where the torque dip occurs.

Mike
Mike Bees

I've heard that 4-2-1 exhausts manifolds can liberate sizeable mid-range torque Mike- upto 12 lb.ft on a VHPD motor. So two questions: will an Elise 4-2-1 manifold fit an MGF and would it be of any benefit for a 1.8i whose only other mods include a high flow filter and exhaust? Since the cost of these things are about 400 quid, it is better to know before hand than later ;o)

Rog- any chance of sending me those power curves? I have the ones that Bruno sent me, but there is not much detail on them. Also, if you still have that picture of the opened exhaust back box, then that'd be much appreciated too!

Rob
Rob Bell

I've seen a power plot from a 220bhp Elise engine with a very trick 4-2-1 exhaust - how does 132lbft at 3000rpm or 142lbft at 4000rpm grab you? Needless to say this was a substantially non-standard engine, but the 'trick' exhaust made up something like 30lbft at low-mid rpm.

As to whether an Elise 4-2-1 will fit an 'F' I don't know - the standard manifolds are the same so there is a good chance. I can put you in touch with a guy who is a good-value source for a well-designed & made (Elise) 4-2-1.

Whether it would be of much benefit on an unmodified K I don't know.

Mike
Mike Bees

Mike, any info you can provide is gratefully recieved.

Cheers

Rob
Rob Bell

Email me your email address Rob.

Mike
Mike Bees

Some claim my VVC engine had to be replaced because of the ICON chip, although the damage seemed to be quite hazardous for just a chip. But if you have like a spare 3000 to replace your engine, no probs!, just go and het one of those chips.

I threw my ICON chip out when it had a new engine. Still have it boxed somewhere.
Dirk

I only had my doubts as to the mapping of the ICON chip. Unfortunately, like most things on this BBS it is impossible to prove, especially with all the other things going wrong as well. I agree, that it would take more than a chip to make dirk's engine do what it did.

If only it had gone wrong at the start, you would have been able to reject it. The ICON chip can be used quite safely as many have proven (I would also tend towards using 98RON if I had one fitted). I hope you have more luck with the BMW (now that won't be hard will it?) At least you won't have to chip it as it will already be fast enough :-)
Tony Smith

>>At least you won't have to chip it as it will already be fast enough :-) <<

maybe just "removing" the 250 kph speed autolimitation ? :))
the M3 would easily do 285 kph, I guess ?
(and 320 in the "Baraque de Fraiture" downhill on the E25, Dirk knows what I'm talking about :))
Fabrice
Fabrice

Roger, So from what you are saying, the K&N + SP worsens the problem of weak mixture, particularly when accelerating. I assume this is the lag I feel or lack of torque when first accelerating.

Would this problem be cured by fitting a power boost valve, would this have alowed an ICON to be used more safely. I assume this gives constantly more fuel pressure thus ensuring a richer mixture. When I was thinking of a power boost valve to cure the K&N/SP lag (a while back now).

I was generally talked out of it by folkes on this BBS, I got the impression many did not think it was a good idea. Has this view changed?
Tony Smith

Rob, I will have a look and dig them out, I am sure they are buried in here somewhere!! I still have that dissected SP behind the garage!

I am far from convinced that the exhaust would benefit that much on a standard or near standard engine. I have little doubt that the clear constrictions of the standard pipes will become more of a problem as power rises and I would suggest that once over 150bhp at the wheels is reached then the potential of this change may well come into the worth doing catagory. Janspeed have some interesting observations on these engines and I shall have to confirm what these were in detail before commenting on them. I have in mind what they are, but my memory is also thinking about the comments by another well known and effective K series tuner.

Tony, the answer is possibly. The fact that whilst many report only positive results form the fit of these two, some also report other not so positive characteristics. This simpy confirms the 'individual' nature of each engine and may well be assisted or even solved by a slightly higher fuel pressure.

Slight adjustmenst in fuelling, especially slightly richer, doesn't have the same disaster potential that ignition timing alteration can have.

Rog
Roger Parker

they tested M3 without limiter, got to 291 km/h... normal, if you know you can go to 250 km/h in 5th, and you still got a 6th gear left!

and I already know where to get the M limiter bypass kit (DM 1,800, yuk!), if it was just to kick some 996 asses ;o)

Fabrice, E411, Neufchateau, downhill towards Brussels, possible to hit revslimiter in 5th gear with an MGF VVC... :p
7250rpm in 5th, I wonder how fast that is (250km/h?)
Dirk

It's the primary lengths that are the weakness rather than the diameter. My ~240bhp K is still using 1.625" diameter primaries (~30" length). Going to bigger primaries generally costs you low/mid-range torque, and like getting greed with cams it's a common mistake to make.

Mike
Mike Bees

This thread was discussed between 06/02/2001 and 16/02/2001

MG MGF Technical index

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