Martyn, Cookstar runs a 321T. Why stick with 2.0ltr for track use?

 

built up 2ltr block
groupe s headers
740 injectors BIGGER THAN REQUIRED I CAN STILL USE THEM FOR MY NEXT BUILD,
tdo5-20G with 10% meth
reverse inlet manifold
apexi power fc Apexi AVCR and EXCELLENT mapping i got 402bhp only hiting 1.5 bar on dyno dynamics proberly due to warm temps.im hiting 1.7 bar geting 425-430 bhp with nice an early spool on the road.got 12.1 1/4 mile time at scooby shoot out could got a better time but due to me missing a few gearshifts as it was my first time on there.b4 i had the builD done i was aiming for 450 but after a chat with neil at slow boy racing HE ASKED WHAT THE CAR WOULD BE USED FOR AND OBVILOUSLY and i told him IT WILL BE FOR FAST ROAD USE AND OCCASINOLY the odd track day he made me relise its not about the Dyno PUB figures its about how it felt on the road i was gona go for a 18G than the 20g but i opted for the 20G cause i wanted the top end power.instead of going for a turbo thats DOUBLE the price that would give me an extra 10bhp to 15bhp slowboy recomended that i spent the money on uprated oil pump, put some money towards the brakes and the suspension and better tyres,gearbox and clutch so i took his advice.THERES NO POINT HAVING THE POWER WHEN A THE GEARBOX,CLUTCH ETC WONT TAKE IT.ITS ALL ABOUT PEACE OF MIND. and i tell you what im more than pleased.what im trying to say is DYNO figures dont help that much on the road.

 

ive a hks gt2835rs garrett dual ball bearing turbo for sale if your interested, it will make 400 bhp on a 2litre no problem.

 

The 2 litre is better suited to race car applications as it puts the power in the right point in the rev range...
The 2.5 with a 321t or similar generally makes peak power at about 5500rpm and then starts to dip , the 2 litre will hold power till 7200rpm and sometimes beyond ....
If a larger turbo is used and the band is shifted up a twee I can't see any problem with using a 2.5....

 

For road use mainly, with my forged 2.0, would a MD321H be a better turbo though?

 

Can't say I have tried an MD321h , but yes that is the common opinion....

 

Agreed on the 321T characteristics on both 2.0ltr and 2.5ltr, I misread and thought you were dismissing a 2.5ltr for circuit use.

 

To quote AndyF's website:

The MD321H is ideally suited to 2.0/2.1 ltr engines aiming for 400 bhp on pump fuel. Boost threshold is similar to a 20G


The MD321T is aimed at the 2.3 and 2.5 conversions, full boost is available before 3000 rpm and the potential for 480bhp and over 500lbft of torque exists.

 

View my scooby for a 2 litre build, it made 440bhp and 385lbft of torque, is getting mapped again soon with minor tweeks and should be well over 450bhp.
Speak to Chy he will build you exactly what you want be it a 2 litre or 2.5, i have had one of each from him

Banny

 

just finished my budget uk98 400bhp + build using a forge 2l engine,sti 4 heads,lateral md321t turbo,frontmount intercooler,standard heatwraped ported headers,3 inch exhaust,uk 6 speed box ,mapped at 1-6 bar at the moment,hoping to get it mapped at 2-2 bar eventually.all done on a budget of 5k using scoobynet,ebay,i thought the turbo might feel a bit laggy but it spools up nicely with the standard ported headers.

 

thanks for the response, well appreciated, when i start the build il document it and post as i go in as much detail and pics as possible. will take a while tho

 

Have you not considered it could be ecu related ?? ie... with a better ecu the car would perform better ??