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MG MGF Technical - More power
|I know that this has been discussed in the past but I was wondering....|
I went to Castle Combe with MG's-on-Track and what a good day it was too! However, the question is...
How can I reliably get some more power out of my TF160, say 185 / 190bhp without sacrificing road "driveability" and without risking a re-build every couple of years. Is this too much to ask of the K series?
Any thoughts, not forgetting cost?
|Hi David, I was at CC yesterday as well - I was in the Japan Cup F. That's the thing with trackdays. They always leave you wanting more power and better handling.|
With regard to your question, you may find that you will improve your lap time (not that we checking these on track days) more by improving the handling and braking of the car. For example, if you haven't got sports pack 1 on your TF then it would be worth looking at lowering springs and uprated dampers.
|I love Castle Combe - was there last year with MGoT :o)|
Getting more tractable power out of a VVC is pretty easy - not necessarily cheap. Both Dave Livingstone and Stu Dickens have somewhere in the 180bhp mark with theirs - and both use them day to day very reliably. I think that Stu's already done 60k miles on his modified engine?
The answer is to have the cylinder head ported, fit a slightly warmer exhaust cam (you can retain the VVC mechanism), a better 4-2-1 exhaust manifold (Janspeed or Piper), a decent back box, a larger 52mm throttle body (that your 160 will already have), and a decent air filter (ITG maxogen would be one option). That's probably a couple of grand's worth of modifications!
If you remove the VVC, you can go for much liarier cams - and if you rebuild the bottom end (better bearings), and have the engine balanced, you can raise the rev ceiling significantly. Which when combined with multiple throttle bodies should see you clear of 200+bhp...
One place you'll find more information is Dave Andrews' website: http://members.aol.com/DVApower/
This will give you some idea of the costs involved - although these don't include fitting etc...
How deep are your pockets? :o)
|Ralph - my TF is an early one so it had Sports Pack 1 - I found that the ride was too firm so I changed the dapers to the VE Solutions 'Comfort Handling'. I thought that this was going to induce too much body roll but I was pleasantly surprised. I have the dampers on the middle setting and for me this is fine. As regards the brakes I've got the 4 pot callipers so there is plenty of stopping power there. |
Was yours the Bronze (sorry if that's not correct) F with the white top?
Rob - deep pockets - there's a thought! Thanks for the link to DVA - I'll check it out later. I would like to have just a little extra juice without going too far adversely affecting the drive-ability of the TF. I think that 185 / 190 a decent level without going too silly (fr me!). will the power only be released at the top end or will it be evenly distributed throughout the range. How realistic are the power gains? I guess the only way is to go on a rolling road before and after.
I don't think that my poor TF went below 4,000 rpm at Castle Combe on Monday. I had one of the instructors shouting in my ear (through the helmet) things like 'balance throught the bend, now POWER'. Great fun! It also made me appreciate that the TF160 is a good car and underrated. I've had the Head Gasket changed to the Land Rover version so I'm pinning my hopes on that...
|Yes, my car was the bronze (Volcano) one with white hard top. In case you're wondering about the spots on the roof, the guys at the garage were at a loose end one day and found some vinyl logos that we had lying around and decided to use them on my roof!|
Okay, so you have already sorted the handling. A bit of extra power is the order of the day, then. As Rob mentioned, Dave Andrews is the Guru of the K4. Having already had your headgasket replaced you can't use this as a justification for porting the head. LOL
Of course, the other way of increasing the power to weight ratio is to reduce the weight of the car. Fitting lightweight seats in place of the heavy standard seats is a start, plus you will be held in place better on the bends.
|[quote] Robb Bell If you remove the VVC, you can go for much liarier cams - and if you rebuild the bottom end (better bearings), and have the engine balanced, you can raise the rev ceiling significantly.[/quote]|
Actually you can't "raise the rev ceiling significantly" owing to the fact the 1800 motor is a stroked 1600.
There are 2 problems here, both due to the short con rod length of the 1800cc motor.
Firstly a short rod causes excessive rod angle leading to bore ovality.
Secondly, and more importantly, a short rod leads to excessive piston acceleration. This is why the stock pistons break up at around 7500rpm and why even forged pistons are unreliable at about 8000 rpm.
Myself and Roger Fabry (who developed the 'Motorsport Head' as well as the 1400cc Turbo MGF Bonneville Race Car) are presently working on a way to modify the K Series Motor to attain a more ideal rod : poston deck ratio, thereby allowing more useable and reliable rpm.
|You're right about the rod angles Deborah - and this is where the level of "acceptable reliability" comes in. What's acceptable? But as Roger will know, there are a number of engines out there that have done good mileages with 8000rpm rev ceilings. |
The way of over coming the rod angle issue is to use a 1.9 or 2.0 litre bottom end but use a 1.6 crank to maintain a 1.8 litre capacity - a short-stroke rather than long-stroke 1.8 litre ... which I believe has been done already in Caterhams?
However, I don't think that David is looking for this level of modification or budget, and is the reason why I only mention it as supplementary information ;o)
Another option I haven't mentioned is NOS - which is where your experience lies Deborah? :o)
Not sure how suitable this is for track days (we'd have to chat to Duncan about that) - for the simple reason that the chances are you'd run out of the gas before the end of the day... :o(
|NOS is perfectly useable on a track day if you set the controller up properly.|
At Silverstone in March I did 7 x 20 minute sessions. I ran out of NOS towards the end of Session 5, but then again, I only started the day with a 1/2 full bottle.
|Ralph - I was planning to use that excuse on my wife but she has seem your comments - that one is out of the window :) |
Rob & Deborah - that was awfully technical.
I want to let some more horses out of the engine without going too far. A few years ago I had a midget that became a monster in the desire for More Power. I don't want to go there again as I'm not that technically minded and I get lost with all the options and tweaks. I just like to give my TF a trashing every now and then!
|David, yes, I know what you mean - too much can be too much! 180bhp seems a reliable target, and certainly this seems to be both Dave's and Stu's experience (keeping the VVC mechanism, porting the cylinder head, fitting a better exhaust manifold, etc etc) - and the result is a very nice engine, very tractable, reliable, good torque characteristics and all retaining the existing rev-limit :o)|
Glad you enjoyed our day at Castle Combe. I'm very much of the same mindset as you:
"not that technically minded and I get lost with all the options and tweaks. I just like to give my TF a trashing every now and then!"
The only difference being my car is an F and has now done over 100K miles of which I guess more than 3K miles have been around tracks around the country.
As Rob said, the easy answer with no downside for reliability is to simply have the head ported. Mine was ported by Dave Andrews when I had HGF at about 35K miles and ever since it has put out around 175bhp at peak with a lovely straight power curve and flatish torque curve. I have standard cams and standard ECU - it behaves like a standard car in every way other than power!
|Rob - that sounds like the area I would like to get to.|
Dave - you do a super job arrange all the track days but don't tell too many people! The only difference between your F and a standard F has been the head ported or are there other mod's - ie 4-2-1 exhaust, air-filter etc.
|>>The only difference between your F and a standard F has been the head ported or are there other mod's - ie 4-2-1 exhaust, air-filter etc.|
The other breathing mods are there David, to allow the ported head to produce the goods, but the big power improvement comes from the porting, once those other things are in place. So, yes, I do have:
* an ITG Maxogen system
* custom exhaust (4-2-1, sports cat and straight through exhaust)
* 52m throttle body
However, the custom exhaust has and continues to have problems. I got the same power without the 4-2-1 and using a standard cat and easily available after-market exhaust (Phoenix in my case).
With a TF160 you already have pretty much the same basis for the breathing. So, I believe you'd see the extra power available from just head porting. The best thing is to talk to the expert - Dave Andrews and see what you feel your wallet can afford.
|I agree with Deborah on the NOS front. I run an 10lb bottle in mine and costs about £50 to fill with a Kryogenic pump from a race garage near me that race 300mph cars at Santa Pod (Webster Engineering). Mine is a wet system that gives a 50bhp shot.|
Hope this is of help...
This thread was discussed between 10/07/2007 and 20/07/2007
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