Suggestions on how to get a better 1/4 mile from a GT

[GroovyCarrot]

Polo_GT, be calm, they're just having a laugh, it's not a dig against you in any way. Most of the things you've listed there are perfectly reasonable, and the rest would definately be things that would go if he was converting the car into a permanent track racer.. just perhaps not practical for a single quarter mile run Anyway, don't take it to heart, no one's trying to rip you for anything

[Tahrey1043]

only playing mate

just taking the "remove the badges" thing to it's logical conclusion

like i know the first bloody thing about 1/4 mile racing anyway?

[polo_GT]

[Steve_O]

Sorry chap - wasn't having a dig at you - just all the obvious things had been mentioned so the thread was just asking to get silly!!

Have you de-wedged your GT??

[tainmrk3polo]

g40_jos de-wedged his and said it produced a massive flat spot @ 4k

[hardhitter]

We are talking about a GT here, which has a completely different throttle body setup and on a n/a engine. Removing the wedge gives a more sensitive throttle and does make a positive difference.

[polo_GT]

A guide to doing it on a g40 which is different but the same principals apply. I know that concept-e has recently done this too his GT so worth having a chat with him.

http://homepage.ntlworld.com/paul.hayes ... ewedge.htm

[polo_GT]

I think that if you are going to do it on a g40 it is worth fitting a superchip aswell as this seemed to get rid of the flat spot on mine. You would see more gain on a tuned engine. It does take a little getting used to pulling away without the wedges as the throttle becomes very light, it is also meant to give you more top end. But then again it might be completely different on a GT.

[GroovyCarrot]

Forgive me for hijacking here, but what does dewedging a throttle body actually do? Keep hearing people talking about doing it, but not having a throttle body to dewedge I've never really worked out what you're all going on about

[Steve_O]

What is dewedging...

Starting with the G40...
In the throttle body, there is a flap which lets air into the engine and is operated directly by the accelerator cable. To this flap is fixed a big metal wedge to keep the airflow smooth at low revs, thus helping pullaways etc.

However, the wedge itself causes a restriction to airflow, thus limiting the amount of air that can get through. The more air you can get into the engine - the more fuel you can burn - the more energy per combustion - the faster you go, etc...

Thus, in the G40, dewedging has proven an effective way to increase performance.

In the GT however...
There are two flaps. The first operates over about the first 2/3 of the accelerator pedal being pressed, with the second opening only in the final third.

The first flap is much smaller than the second (about the size of a 10 pence piece) and is the only one of the two to have a wedge on it.

Therefore, it is debatable as to whether removing it would make as much difference as it does on the G40, where the wedge is MASSIVE!!!

[Steve_O]

We are talking about a GT here, which has a completely different throttle body setup and on a n/a engine. Removing the wedge gives a more sensitive throttle and does make a positive difference.

Thanks for giving me the definitive word on that Dan!!

I had heard before it makes a noticable difference when combined with other airflow mods - but never heard about any of the downsides...

I think a sharper throttle would suit my driving style more - so when I feel like getting my hands mucky and cleaning up that whole area - I'll probably give it a go!!

[amstrange1]

We are talking about a GT here, which has a completely different throttle body setup and on a n/a engine. Removing the wedge gives a more sensitive throttle and does make a positive difference.

Thanks for giving me the definitive word on that Dan!!

I had heard before it makes a noticable difference when combined with other airflow mods - but never heard about any of the downsides...

I think a sharper throttle would suit my driving style more - so when I feel like getting my hands mucky and cleaning up that whole area - I'll probably give it a go!!

Yoof's GT is certainly more willing to rev with his mildly ported and dewedged TB on. I ran it on my car when I had a 3F lump in there (whilst getting the G40 rebuilt) and along with a TB elbow with the orange vacuum switch removed, G40 exhaust manifold and downpipe, and one of Dan's chips it was pretty nippy for a GT. Didn't feel as torquey as a stock one though. Still hit the limiter in 5th though one night...

[Steve_O]

Hit the limiter in 5th?? - Blimey!!!

I will do it as I can always undo it - tho could be a bit of a pain if I use rivets to block the holes!!

Any advice in this respect - I'm guessing it does leave holes like on the G40??

[hardhitter]

When you do it, the screws going into the wedge break, so it won't be easy to reverse (unless you keep a spare tb). The two holes can be filled with pop rivets which is the best option, i will try and get round to doing a faq depending on time.

Andy I have a feeling the G40 exhaust manifold might affect torque on a GT with the runners being un-equal lengths.

[amstrange1]

Ye, see where you're coming from Mr 'field. But found that most of the flow mods I did to it made the power more peaky - and didn't lose torque, just moved it up the rev range. The rev limit certainly felt too low.