Carb conversion
Discussion
the kowalski said:
I'm taking my 500 HC off the road in Nov, and i'm going to do an engine rebuild. I'm going to ditch all the emission crap, ECU, and fit a Carb. Has anyone else done this and does anyone know of a suitable manifold ?
Thanks.
Chris
Thanks.
Chris
There's a bloke on here called 'apache'. He did the same as I recall, maybe worth a chat with him, seems a nice enough bloke.
Because i've spent a bloody fortune trying to get it to run right !( with 0 success) I'm a big fan of "old school" engineering, I hate engine management systems, and I know I can get more power and smoother running by converting to a carb.
Some of the work has already been done by a previous owner. Stage 2 Heads, High lift Cam, Lightened Flywheel and a Left-Hand Winkey Valve !!
I also plan to do a light coversion ( front and rear ), new paint, Upgraded suspension, wheels, bla bla bla........ You get the picture
Chris
Some of the work has already been done by a previous owner. Stage 2 Heads, High lift Cam, Lightened Flywheel and a Left-Hand Winkey Valve !!
I also plan to do a light coversion ( front and rear ), new paint, Upgraded suspension, wheels, bla bla bla........ You get the picture
Chris
Jools, maybe a carb conversion is what I need, have now spent a small fortune on the beast, engine blueprinted, performance cam, re bored with crank lightened and balanced, heads polished and ported. The list goes on... and still it runs like a bag of crap at steady low speeds.Went through the 40 mph bit on the M6 the other day and it was jerking and jumping all over the place.At a loss now...
petros said:
Jools, maybe a carb conversion is what I need, have now spent a small fortune on the beast, engine blueprinted, performance cam, re bored with crank lightened and balanced, heads polished and ported. The list goes on... and still it runs like a bag of crap at steady low speeds.Went through the 40 mph bit on the M6 the other day and it was jerking and jumping all over the place.At a loss now...
Could it be the performance cam and heads have moved the power higher up the rev range and caused the problem? I once ran a race cam and high compression in my old mini, it had nothing below 3000 rpm and would cough and splutter like crazy but once opened up it was worth it
I find my standard 500 shunts a little at low speeds but after driving a while I tend to smooth it out without thinking.
Hi David, I was running the non cat resistor with cats and pre cats in place for over a year with no probs, (obviously just had to swap it for MOT). I have recently removed the pre cats (which were in perfect condition I might add) and had a new catless Y piece made - just because I always had the niggley feeling that I would be wrecking the main cat.
Hasn't made much difference really - sounds a bit better and pops nicely. Possibly feels a bit more powerful but could be in the mind!!!!!!!
Lig.
Hasn't made much difference really - sounds a bit better and pops nicely. Possibly feels a bit more powerful but could be in the mind!!!!!!!
Lig.
lig said:
Hi David, I was running the non cat resistor with cats and pre cats in place for over a year with no probs, (obviously just had to swap it for MOT). I have recently removed the pre cats (which were in perfect condition I might add) and had a new catless Y piece made - just because I always had the niggley feeling that I would be wrecking the main cat.
Hasn't made much difference really - sounds a bit better and pops nicely. Possibly feels a bit more powerful but could be in the mind!!!!!!!
Lig.
Hasn't made much difference really - sounds a bit better and pops nicely. Possibly feels a bit more powerful but could be in the mind!!!!!!!
Lig.
Cheers Lig, I'll give it a try then.
I was worried that it might overheat the main cat.
I was thinking "hmm that Lig might drive like a pussy, so his cat might not get too hot", then I checked your profile pic
I'll give it a try!
I like carbs.
you won't get them running smoother with ECU, and mine drives like a pussy on 1cm of throttle travel! (70mph!)
single carb, double pumper would be the best solution. will also fit under the bonnet. got enough power for 7L chevys! or 5L cobras/ultimas!
I stuck with four as its std TVR spec (Tuscan)
mines got a faily wild cam/engine.
andy
tvrmonster
BTW lig...damn attractive car IMHO
you won't get them running smoother with ECU, and mine drives like a pussy on 1cm of throttle travel! (70mph!)
single carb, double pumper would be the best solution. will also fit under the bonnet. got enough power for 7L chevys! or 5L cobras/ultimas!
I stuck with four as its std TVR spec (Tuscan)
mines got a faily wild cam/engine.
andy
tvrmonster
BTW lig...damn attractive car IMHO
Guillotine - thanks!!
David, interesting comment.....but....I have been informed that the problem hot cat will be at tickover low revs. This is because with the GTR the ECU is running a much richer fuel map, so chucking loads of fuel in at lower revs, when it reaches about 3-4k revs the llamdas are no longer used (this is the change over point - why some Griffs (especially mine) used to jerk like a turbo was cutting in at about 3.5k revs - the GTR totally eliminated this) and with either the WTR or the GTR after this point the fuelling will be the same (so I have been told)!!
I had read that the cat would overheat and 'explode' which scared me...but I have never read of this actually happening, it was mainly from some bloke who sells modified ECU chips!! - I tried one of these chips and it made a subtle difference, but the car ran much better with the GTR than the chip!! (the only difference was the fuel economy which was much better with the chip).
The other intersting thing is that with the WTR the engine limiter cuts in at about 6k revs where as with the GTR it doesn't, I have had it to about 6700 but didnt want to take it past that....interesting....
All i can say is that it is well worth giving the GTR a try, you will have to slightly modify the AFM settings (I find the best setting is 1.5v), reset your ECU and thats it!!
It really did transform my car, from it always annoying me in 30 40 zones to loving it!!!
let me know how you get on!
Lig.
P.S Apologies to 'the kowalski' for hijacking his thread!!
David, interesting comment.....but....I have been informed that the problem hot cat will be at tickover low revs. This is because with the GTR the ECU is running a much richer fuel map, so chucking loads of fuel in at lower revs, when it reaches about 3-4k revs the llamdas are no longer used (this is the change over point - why some Griffs (especially mine) used to jerk like a turbo was cutting in at about 3.5k revs - the GTR totally eliminated this) and with either the WTR or the GTR after this point the fuelling will be the same (so I have been told)!!
I had read that the cat would overheat and 'explode' which scared me...but I have never read of this actually happening, it was mainly from some bloke who sells modified ECU chips!! - I tried one of these chips and it made a subtle difference, but the car ran much better with the GTR than the chip!! (the only difference was the fuel economy which was much better with the chip).
The other intersting thing is that with the WTR the engine limiter cuts in at about 6k revs where as with the GTR it doesn't, I have had it to about 6700 but didnt want to take it past that....interesting....
All i can say is that it is well worth giving the GTR a try, you will have to slightly modify the AFM settings (I find the best setting is 1.5v), reset your ECU and thats it!!
It really did transform my car, from it always annoying me in 30 40 zones to loving it!!!
let me know how you get on!
Lig.
P.S Apologies to 'the kowalski' for hijacking his thread!!
Edited by lig on Thursday 31st August 09:36
Various Holley 4 barrels and right manifold should do it 650cfm likley fine unless it is a very modded engine.
Downdrafts are the Dogs danglies but really cost go out of tune, I mney no object this is the route but can get 98% of Quad webber stack with the right Holley, what I am going to do on my racer.
Downdrafts are the Dogs danglies but really cost go out of tune, I mney no object this is the route but can get 98% of Quad webber stack with the right Holley, what I am going to do on my racer.
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