Hi, does anybody know the inlet size of a standard 20v turbo please,
cheers mike

which measurement, spigot OD for a hose, compressor inducer?

Its the internal air inlet side please

Comp wheel is a 50 trim T3, 42mm inducer

Ok, thanks for that. Is there anybody on the forum that has experience of 20v tuning that could help me, as I need to drop to a 34mm restrictor to comply with rally regs. ??

Hi Mootch. I tune 20VTs so I may be able to help. What info are you after?

Hi kj,
well I just wondered if tuning the 20vT using a 34mm restrictor was possible without big expense, from my past experience rallying an escort cosworth turbo it limits breathing at high revs, however using anti lag, fmic, water injection, and other engine management I could get 300 bhp and great torque, but that was also with 4 wheel drive.
I would be happy to get around the 250 as fwd is a limiting factor.
I've never seen a coupe on a tarmac stage, but why not, would be different and good fun.

It's fairly simple to get to 250 bhp you can get it remapped to achieve around this value. Is this doable with the regs?

To get to 300 bhp you'll need a slightly larger turbo, hybrids are good for this, with FMIC, remap and a free flowing exhaust.

As for 250 bhp being the limit for FWD, well a few years ago Nigel ran his Coupe at Ten of the Best and won the FWD class for 3(?) years running, up against much lighter Novas and Civics etc. He would have been mid table in the RWD class.

Good luck in your class and be sure to post how you get on

[quote=Gunzi]It's fairly simple to get to 250 bhp you can get it remapped to achieve around this value.
The problem might be getting 250 with a 34mm restrictor fitted

The restrictor may be a problem with the OE turbo. Can you upgrade the turbo?

With the correct set-up, I think we could still achieve 250bhp on the standard turbo with 34mm restrictor. Peak power as standard is circa 5800rpm, so even with the restrictor limiting revs, with the right set-up and tuning we can maximise torque and power up to 5500rpm.

Other than the restrictor, are then any other regulations to limit the engine?

Sounds really interesting Mootch!
I have always loved rallying and use to regularily spectate in the early 90's when it was the big 4x4's sierras celica Subaru legacy etc and still called the "Lombard rac rally" used to love it and fancy doing it myself one day!
Always wondered how well a coupe would do in a rally? I know there was an Italian team many years ago and think they did the monte but don't know much more

You could always fit one of those special celica restrictors!

Would love to know how you get on so keep us informed how you get on!

250 bhp is certainly no problem on the stock turbo. With the 34mm restrictor the turbo would have to work harder and produce more heat, but it should still be do-able. a medium size front mount intercooler will keep inlet temps within reasonable limits.

BTW, do the regs. limit you to the stock turbo?

Thanks for some interesting answers.
the only rule requirement is the fitting of a 34 mm restrictor which has to be 75mm from the turbine blades, other than that I can use hybrid turbos, anti lag, any management system etc. My cossie had a small turbine mated to the standard compressor which gave really quick spool up, it ran out of steam top end but that was fine, you just threw the gears at it.
on another note are all final drive ratios the same, is the 6 speed box closer ratio, plus I have read about fitting alfa internals to achieve closer ratios, any clues?
Tbh I dont want it to cost the earth, its just a budget project for fun, although I do think that you might get a few decent results. ?.and of course it would sound fantastic on a stage.

Both the Coupe 5 & 6 speed have long ratios, so no benefit to changing. The Alfa 6-speed however has much shorter ratios, so certainly better for keeping the engine in the torque zone.

For the turbo we have quite a few choices, but the hybrid option is going to give the best return for torque spread with maximum response. Management side, well no requirement to change, the factory Bosch ECU is actually good for 600bhp+, indeed 622bhp is our current record although I think we may see 700bhp from a Coupe next year...

Flea,
that sounds very interesting, do you have any parts in stock, as in used but good etc, I take it that you can remap the standard ecu to suit.
will the alfa box fit straight on, or is it a case of swapping internals.
Are there any fibre glass bonnets available, sorry for all the questions. This might be a goer !!

You have to take the alfa gear kit and put it into the coupe box for it to work mate

Yes mapping the standard ECU is no problem, approaching 600 cars to date, just ask away on here!

If you can let me know your thoughts on where you really want to take it I'll advise on the best way forward.

is this a common mod on the performance coupes, also which alfa ?

well I guess its as much as possible within the boundaries of the 34mm restrictor and keeping things very driveable with quick spool up

That is very doable, I developed a hybrid turbo last year that is designed for maximum response i.e. no different to standard, but with significant increase in mid-range torque.

Please send me a message on here, or email/Facebook so that I can reply to you tomorrow with options.

No it's not that common and I've only heard of a few people ever doing it, also with the alfa gear kit top out speed is 165mph from what I've been told due to not fitting mine in the car yet I don't know how true this is.

It's not common but have a look at this project thread. http://www.fiatcoupeclub.org/forum/ubbthreads.php?ubb=showflat&Number=1176214&page=2