Tuning tunning my 20v turbo coupe

[Muhab Radwan]

hi,
i need some help to retune my coupe 20v turbo.......i bought a new bigger turbo, law compression pistons and rods but i can't find the main bearings.... can i use stock bearing to reach 1.8 bar of boost........ and how to remap my ecu..........

 

[NigelO]

Please list your specifications...

What turbo have you bought?
What make of pistons (and what compression ratio?)
What make of rods
What other modifications (intercooler, intake, injectors, fuel pump, spark plugs, exhaust, boost control, etc etc)

And at the risk of sounding like an old git, what modifications to you intend for the chassis and brakes? A 20VT only just has enough brakes and chassis to cope with standard power - increasing the power without improving the chassis and brakes is a sure way of visiting the scenery when you try to push it. You think I'm joking? - a 300bhp Coupe is easily capable of 165mph. With 400bhp, you're going to be closing in on 175mph. With 450bhp, you'll be doing 0-100 in less than ten seconds and you'll be out-accelerating a Lamborghini Diablo - you absolutely must allow for some expenditure on the suspension and brakes.

 

[ChrisUK]

:yeahthat:, The ingear strait line grunt of these things is unreal.

As for bearings I'm sure I've seen other cars running 350bhp+ on standard crank bearings etc.

But as Nigel said it all depends on the other factors.

 

[NigelO]

As for bearings I'm sure I've seen other cars running 350bhp+ on standard crank bearings etc.

True - I'm running over 450bhp on a standard crank. Its now done well over 200,000 miles - a testament to the original engine design. I'm running lightened and balanced forged rods and pistons, which probably gives the crank a slightly easier time, but I also run an increased rev limiter and boost as high as 1.7 bar, which more than makes up for the reduced weight of the piston/rod assembly.

You definitely don't need to upgrade the crank journals, you just need to make sure you're running a good quality oil.

 

[Muhab Radwan]

i'm still need a help to choose piston and rod (woosner or pure performance) comperation ratio of 8.0:1........... i already bought gt30 ar 70 ballbearing turbo

 

[NigelO]

I run 1mm oversize Accralite pistons (83mm) with an increased compression ration of 9:1. For rods, I bought the best I could find - Cunningham

 

[Muhab Radwan]

ok... what about pure performace pistons and rods is it ok or woosner with cunningham is better...(i'm using gt30 70 A/R and wich bore and compression ratio should i choose for about 1.8 bar of boost

 

[Muhab Radwan]

hi....
i finally got my pistons ans rods from pureperformance and i'm installing it right now..... i'm now ready to go but i'll still need help to reflash my ecu how can i do it?

 

[NigelO]

This is going to end in tears....

You simply cannot run 1.8 bar on these engines without an awful lot of supporting mods. I asked earlier what other modifications you have made - you'll need a lot... Without this information, I can't help you.

You also ask about re-flashing your ECU - you can't (at least not without a lot of expensive kit, Eprom emulators, wideband AFR meters and a lot of mapping knowledge)

finally, you ask what bore and CR you need to give 1.8 bar of boost - this worries me, because bore and CR is irrelevant to boost. Its the turbo that gives boost, not the pistons. Sure, a lower CR will be able to handle bigger boost more readily, but off-boost driving will be adversely affected.

 

[Lucky Luke]

finally, you ask what bore and CR you need to give 1.8 bar of boost - this worries me, because bore and CR is irrelevant to boost.

Really??

Those two elements are VERY dependent on boost. The bigger the bore, the thinner your cylinder walls and the less boost you can run.

And the lower your CR, the more boost you can run.