Results of todays rolling road tune up..
Discussion
150 bhp at 5600 and general feeling is that whilst nothing is wrong, its not quite got the go I thought it might.. Confirmed by the chap that did the test and younger brother, (both considerably more experienced than I in terms of cars..)..
Its a decatted S3C, K&Ns at the front, straight through stainless exhaust, (actually starting to wonder if its too loud).
Nah, sounds beautiful..
The computer says everything is ok, there is no pause when I gently boot it, (or even boot it hard), everything checks out..
I'm wondering if it sounds better than it goes; being very loud you'd maybe expect to be thrown into the back of your seat, but you're not. I'd have not even thought about it if the reading was close to what the bible says i.e. 168 bhp.
Not worried, but curious. Sound ok to you folks?
Its a decatted S3C, K&Ns at the front, straight through stainless exhaust, (actually starting to wonder if its too loud).
Nah, sounds beautiful..
The computer says everything is ok, there is no pause when I gently boot it, (or even boot it hard), everything checks out..
I'm wondering if it sounds better than it goes; being very loud you'd maybe expect to be thrown into the back of your seat, but you're not. I'd have not even thought about it if the reading was close to what the bible says i.e. 168 bhp.
Not worried, but curious. Sound ok to you folks?
I recently found the print out of the session I had with my S4. Power was around 158bhp if I remember correctly (about 85,000 on the clock).
Bear in mind that absolute figures are unlikely so don't take too much notice of the actual numbers unless you're comparing the before/after effects of a change.
Bear in mind that absolute figures are unlikely so don't take too much notice of the actual numbers unless you're comparing the before/after effects of a change.
The last session I had with mine was at Power Engineering and the following were the startling figures. At the time the clock 95,000 on it !
178 bhp & 192 lbs ft torque.
This would have been at the flywheel though and not at the wheels.
The torque is the one that is very startling, and shows that getting the correct fueling will do for a V6 S ! Both bhp and lbsft were above book on a car that had done nearly 100,000 miles.
The only work that had been done to the heads was to remove them and clean them completely and regrind the valves when I replaced the exhaust manifolds.
The fueling was changed by winding up the fuel pressure regulator a little and the rest was down to getting the timing right and having a TP that misread marginally at a certain Temp.
The exhaust was a ACT performance products jobby and really helped the car breathe without removing too much back pressure, which is what my previous exhaust was doing. You could feel it at the top end.
150bhp doesn't sound that bad and when you factor in all the variable with rolling road sessions which are inumerable then it is OK. But is only OK. I reckon there is more in there without having to spend masses on tuning etc etc and other parts etc etc ..
Good luck.
178 bhp & 192 lbs ft torque.
This would have been at the flywheel though and not at the wheels.
The torque is the one that is very startling, and shows that getting the correct fueling will do for a V6 S ! Both bhp and lbsft were above book on a car that had done nearly 100,000 miles.
The only work that had been done to the heads was to remove them and clean them completely and regrind the valves when I replaced the exhaust manifolds.
The fueling was changed by winding up the fuel pressure regulator a little and the rest was down to getting the timing right and having a TP that misread marginally at a certain Temp.
The exhaust was a ACT performance products jobby and really helped the car breathe without removing too much back pressure, which is what my previous exhaust was doing. You could feel it at the top end.
150bhp doesn't sound that bad and when you factor in all the variable with rolling road sessions which are inumerable then it is OK. But is only OK. I reckon there is more in there without having to spend masses on tuning etc etc and other parts etc etc ..
Good luck.
The only significant difference on mine is the exhaust; I'm wondering if I'm suffering from lack of back pressure. Can't say why, but its just a feeling.. I'll talk to the guys that built it. I've a feeling it was custom built but can't remember by whom..
Reckon once I've checked the usual things, (plugs, leads etc) I'll look at the fueling as johno suggested. Its not been used much for a while before I bought it, so could be suffering from only taken out in the summer and isn't used to being opened up syndrome, (for want of a better way of describing it). Couple of long runs should sort that out..
The figures I got were at the wheel, not the flywheel so its ok, but only ok. I'll let you know how I get on..
Reckon once I've checked the usual things, (plugs, leads etc) I'll look at the fueling as johno suggested. Its not been used much for a while before I bought it, so could be suffering from only taken out in the summer and isn't used to being opened up syndrome, (for want of a better way of describing it). Couple of long runs should sort that out..
The figures I got were at the wheel, not the flywheel so its ok, but only ok. I'll let you know how I get on..
PetrolTed said: I'm sure the exhaust on mine is stifling performance. The squashed down pipes must be restricting the exhaust badly. Trouble is they get knackered again within days of being replaced. Has anyone else suffered from this problem and found an effective solution?
Ted,
The only real solution to this is to uprate the springs. I even had my overall ride height lower than standard yet still did not suffer with crushed pipes and was using the car everyday.
I would recommend 400 lbsft front and 300 lbsft rear with new dampers (depends on the condition of your current ones) If the current dampers are OK you could just change the springs.
I found these spring rates the best compromise between ride quality and occasional track use. They also mean the car doesn't squat so badly and therefor they help protect you exhaust ... economical in the long run !
Psycho,
It is also worth making sure that the TP is reading correctly, the HT leads are decent 8mm silicone ones (mine were motorcraft ones)
The whole system needs to be in tip top condition.
It is possible to buy rising rate fuel regulators and adjustable ones. I do not have experience of these, but some of the guys on the group do so.
I would say though that none of them will give you massive increases and that investing in another RR session after any modifications is the best way to realise any possible gains.
Good luck ! Must say that when Power Eng. had finished with mine it was a diffenrent car. It did really make all the hours I had spent cleaning the heads etc worthwhile ...
One area which has shown significant performance increase in performance for little outlay is to have the heads off and have the valve reground with 3 angle valve seats.
PaulV's old S had this and even with my new found power mine was not as quick as his on Top End.
Even Pete Humphries when we were out at Zolder was shocked at how quick Paul's car was. Didn't cost him a lot of money.
It is also worth making sure that the TP is reading correctly, the HT leads are decent 8mm silicone ones (mine were motorcraft ones)
The whole system needs to be in tip top condition.
It is possible to buy rising rate fuel regulators and adjustable ones. I do not have experience of these, but some of the guys on the group do so.
I would say though that none of them will give you massive increases and that investing in another RR session after any modifications is the best way to realise any possible gains.
Good luck ! Must say that when Power Eng. had finished with mine it was a diffenrent car. It did really make all the hours I had spent cleaning the heads etc worthwhile ...
One area which has shown significant performance increase in performance for little outlay is to have the heads off and have the valve reground with 3 angle valve seats.
PaulV's old S had this and even with my new found power mine was not as quick as his on Top End.
Even Pete Humphries when we were out at Zolder was shocked at how quick Paul's car was. Didn't cost him a lot of money.
spnracing said: 400lbs front springs on an S? Gulp. I run 450lbs on the back of my race car and 275lbs on the front (its FWD). And that feels like a bag of nails on the road.
Does anyone know what the standard spring rates were on the S? I'm sure they were nowhere near 400/300?
They vary as you would expect and I have seen ratings from 160lbsft to 220 lbsft.
I know one S which is running 700 front and 550 rear and the ride quality is very good.
Peter I believe is running 600 front and 500 rear ( I stand to be corrected)
The ride quality is also effected significantly by the quality of the dampers being used with these springs. With very high spring rates you can run very low damper settings.
The ride quality in my S was firmer than standard, but not harsh or uncomfortable. Remember I was doing 23,000+ miles a year in it, plus trackdays.
I would have happily gone to 600 front and 500 rear but it would have needed revisions to the ARB and better quality dampers and then I would have been getting further away from the character of the car.
If you look at some of the shots of my car at Zolder this year I couldn't believe how much it still appears to be rolling like a barge !
PetrolTed said:
johno said:
The only real solution to this is to uprate the springs. I even had my overall ride height lower than standard yet still did not suffer with crushed pipes and was using the car everyday.
Ah... very good point. I'm sure mine are pretty shagged. I'll get that sorted too.
I would say that if the springs are the original units then they must have lost their integrity by now, purely through the number of miles, trackdays, using the car to lug all that merchandise around and general wear and tear that TVR's throw at their suspension in general.
Might be worth a look at least.
johno said: If you look at some of the shots of my car at Zolder this year I couldn't believe how much it still appears to be rolling like a barge !
I had 350/600 on the race car and reduced the rates (and the lap times).
A stiffer spring will take more force to compress but on a fast corner the car will still roll. The way to stop that is to fit a shorter spring - and maybe then a stiffer damper setting.
But then you really do get into bone rattling territory. My S rolled like a barge - but it was a good laugh. Looking back it could probably have done with a new set of springs too.
I thought the conventional wisdom with suspension was that by using good quality stiffish dampers you can get away with plusher spring rates. basically the car will roll more, but the actual body control should be very good maintaining contact patch on the road etc... Also softer springs aid traction and should make the car more predictable / controllable.
Of course all this is great for road use, but on track you'll surely be wanting the stiffest springs you can throw at it...
Of course all this is great for road use, but on track you'll surely be wanting the stiffest springs you can throw at it...
I fitted a set of shortened variable-rate springs to my 3000S a few years ago and it improved things tremendously. I'm planning some tricks using front and rear anti-roll bars for next year (yeah, I've said that for the past 3 years, I know!) so keep a look-out for me in your mirrors at Zolder, Johno, I'll be coming through
spnracing said: A stiffer spring will take more force to compress but on a fast corner the car will still roll. The way to stop that is to fit a shorter spring - and maybe then a stiffer damper setting.
trackdemon said: Of course all this is great for road use, but on track you'll surely be wanting the stiffest springs you can throw at it...
With 350/600lbs springs I could do 1.31 round Snetterton.
With 275/450lbs springs I can easily do a 1.29.
The car feels more controlled and the driven wheels don't 'bounce' as you power out of the corners.
Actually there were some other changes to the car too so its not a fair comparison - but I won't be going back to stiffer springs.
To go too stiff with springs can increase under steer, bump steer, nervousness and whole range other issues on track. Even more so on the road.
Peter H and SPN have far more experience of this than I. It is possible to dial out some of the issues that stiffer springs creates through ARB adjustments, damper settings, geometry, ride height etc
Ultimately for a road car with occasional track use you are looking to get the best compromise between the 2 arena's ...
SPN,
Would love to come and see you campaign the Golf. Used to have a MKII GTi which I still consider to be one of the greatest cars evr made. Always wanted a MKI though ..
Spent 4 laps trying to get passed a trick MKII at Anglesey this year in the Griffith, was real fun chasing him round !
Peter H and SPN have far more experience of this than I. It is possible to dial out some of the issues that stiffer springs creates through ARB adjustments, damper settings, geometry, ride height etc
Ultimately for a road car with occasional track use you are looking to get the best compromise between the 2 arena's ...
SPN,
Would love to come and see you campaign the Golf. Used to have a MKII GTi which I still consider to be one of the greatest cars evr made. Always wanted a MKI though ..
Spent 4 laps trying to get passed a trick MKII at Anglesey this year in the Griffith, was real fun chasing him round !
The current provisional calendar is;
Thruxton 30th March
Rockingham 12-13th April
Brands Hatch 17-18th May
Lydden Hill 31st May
Mallory Park 15th June
Croix en Ternois19-20th July
Silverstone 16th August
Pembrey 24-25th August
Cadwell Park 7th September
Oulton Park 27th September
and I generally have some tickets left over - drop me an email. But you have to promise not to laugh hysterically when I stuff the thing into the armco. Again.
Thruxton 30th March
Rockingham 12-13th April
Brands Hatch 17-18th May
Lydden Hill 31st May
Mallory Park 15th June
Croix en Ternois19-20th July
Silverstone 16th August
Pembrey 24-25th August
Cadwell Park 7th September
Oulton Park 27th September
and I generally have some tickets left over - drop me an email. But you have to promise not to laugh hysterically when I stuff the thing into the armco. Again.
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