Throttle Responce / Pick Up
Discussion
Can it be improved ?
Just picked up a 98 MX5 1600 ( don't laugh , it's for Hissy ) And ime shocked at how quickly it builds revs , with a lovely light and very positive throttle action, which makes it a quick little car for its engine size .
Ime guessing a Left Hooker Griif is better I'n this respect due to the positioning of the Throttle Cable ?
Not had a chance to see what Injection System the MX is fitted with . Ime fully aware that the 500 isn't a rever like a 400 is and like wise a 3.8 E Type is far more responsive than the later 4.2 engine.
My Griff has been played about with and was dynod @ just under 300 a few years ago.
Would a lighter flywheel help ? As this mod vastly improves the E Type. A faster throttle Responce and pick up would make the Griff a lot quicker and maybe stop the 911 Jackos getting away from me !
Just picked up a 98 MX5 1600 ( don't laugh , it's for Hissy ) And ime shocked at how quickly it builds revs , with a lovely light and very positive throttle action, which makes it a quick little car for its engine size .
Ime guessing a Left Hooker Griif is better I'n this respect due to the positioning of the Throttle Cable ?
Not had a chance to see what Injection System the MX is fitted with . Ime fully aware that the 500 isn't a rever like a 400 is and like wise a 3.8 E Type is far more responsive than the later 4.2 engine.
My Griff has been played about with and was dynod @ just under 300 a few years ago.
Would a lighter flywheel help ? As this mod vastly improves the E Type. A faster throttle Responce and pick up would make the Griff a lot quicker and maybe stop the 911 Jackos getting away from me !
Remember that gearing will have a large impact on how quickly a car appears to rev up...
GF's MGF appears to rev up v.quickly - but gear ratios are v. short.
Had this in my Rover Tomcat turbo when running a NASP box - replaced the correct (longer ratio) turbo box and it appeared to build revs more slowly - but was in fact a faster car than before (fewer gear changes to reach a given speed).
HTH,
Dom
GF's MGF appears to rev up v.quickly - but gear ratios are v. short.
Had this in my Rover Tomcat turbo when running a NASP box - replaced the correct (longer ratio) turbo box and it appeared to build revs more slowly - but was in fact a faster car than before (fewer gear changes to reach a given speed).
HTH,
Dom
It can definitely be improved, my engine was transformed, incredibly eager compared to standard 500. An ACT double or triple throttle bodied plenum could form part of the solution alongside other mods. Search for Chilliman on the Chimaera forum, seems pleased with his recent work. It's not cheap but it's doable.
Julian
Julian
This is interesting; for me improving the throttle response is way more important than the outright HP figure.
I have tried a few things but the three fairly inexpensive mods that have made a big difference on my car were.
1) Lightened standard flywheel £80
2) ACT smooth bore elbow (plenum to AFM) £45
3) SC-Power plenum spacer & trumpet bell mouth kit £180
Of the three, the biggest difference was the lightened flywheel.
I needed to replace my clutch so an extra £80 and 10 minutes work was a no brainer, the result was a very noticable improvement in the way the engine spins up.
My next step is to increase the size of the throttle body to 72mm; sadly I just can’t justify the cost of an ACT triple plenum.
Finally I am looking at combining the bigger throttle body with a throttle cable cam.
The idea being the cable cam will give the standard 1:1 ratio for the first 25% of throttle pedal travel, followed by a progressively greater throttle opening for less & less pedal movement.
This is a common mod on motorcycles and can do an excellent job of tricking your brain into believing the throttle response has been improved, the truth is it's just a trick.
But an effective one.
I have tried a few things but the three fairly inexpensive mods that have made a big difference on my car were.
1) Lightened standard flywheel £80
2) ACT smooth bore elbow (plenum to AFM) £45
3) SC-Power plenum spacer & trumpet bell mouth kit £180
Of the three, the biggest difference was the lightened flywheel.
I needed to replace my clutch so an extra £80 and 10 minutes work was a no brainer, the result was a very noticable improvement in the way the engine spins up.
My next step is to increase the size of the throttle body to 72mm; sadly I just can’t justify the cost of an ACT triple plenum.
Finally I am looking at combining the bigger throttle body with a throttle cable cam.
The idea being the cable cam will give the standard 1:1 ratio for the first 25% of throttle pedal travel, followed by a progressively greater throttle opening for less & less pedal movement.
This is a common mod on motorcycles and can do an excellent job of tricking your brain into believing the throttle response has been improved, the truth is it's just a trick.
But an effective one.
Edited by Chimpafrolic on Thursday 22 September 20:01
Thanks for replys . I was wondering re the Lightened Flywheel. I know it works wonders for the XK Engine, ( Alloy ) but asumed that TVR would have specified a Light Flywheel for the Griff.
I was severly embarased by 3 dudes, (the driver must have been 20 stone, yes really ) in Very Doggy looking 4 Door Sierra Saphire Cosworth last summer. It wasnt a std one and i know those Cossies can be made to produce serious HP. but they just shouldnt have got the drop on me. Like wise the Jacko in the 07 plate 4S.
For me the Worst Aspects of the Griff are the Slow Engine pick up and Heavy , Slow gear change. I am still waiting for my Engineer Pal to turn me up a longer gear lever to help speed up the gear change.
Is the Griff Flywheel steel ? How much can it be lightened by ?
I was severly embarased by 3 dudes, (the driver must have been 20 stone, yes really ) in Very Doggy looking 4 Door Sierra Saphire Cosworth last summer. It wasnt a std one and i know those Cossies can be made to produce serious HP. but they just shouldnt have got the drop on me. Like wise the Jacko in the 07 plate 4S.
For me the Worst Aspects of the Griff are the Slow Engine pick up and Heavy , Slow gear change. I am still waiting for my Engineer Pal to turn me up a longer gear lever to help speed up the gear change.
Is the Griff Flywheel steel ? How much can it be lightened by ?
Trust me an LT77's change is poor compared to the T5. I have a V8S and a Griff and the difference is significant - I've also used T5's over many miles in both a Cerb and a RV8 Tuscan Challenge car. Interestingly I used a gear lever extention in the Tuscan (more to do with seat positioning than anything else) and I would say that it did not improve leverage or action, if anything it made it more vague, although not dramatically so. I'd suspect some mechanical issue with the box (linkage?) if the gear change with a T5 is vague or sloppy. 
Edited by Keithyboy on Friday 23 September 15:05
Guys, the 500 lump already has a very light flywheel, I may be wrong but I'm pretty sure it's inadvisable to make it any lighter. I've just had my engine rebuilt by V8 Developments, and the throttle response is light years difference to the previously (near standard) original engine. It's been extensively modified, has the ACT triple plenum, and runs on MS2. It spins up to 6.5K in no time at all. It's probably a combination of all the mods that makes it so responsive, but I'd thoroughly recommend talking to V8Dev before deciding on which route to go.
Oh, and it's very very very quick
Oh, and it's very very very quick
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