thinking about a 2.5 standard sti or a crowford upgrade

at the moment my car 93 wrx ,tdo5/6 20g,power fc,fuel pump+reg,550 injectors,hybrid front mount,apexi afcr,3 inch decat,grouppe s headers and uppipe,

6 speed box in the pipeline

what else would i need,what cost and what about the power that this would produce.

cheers david

 

not sure about power but scoobyclinic do a 2.5 upgrade from £4500.

 

Power will be little or no different, it is turbo related, so about 400 BHP on Optimax. But far more driveable and much quicker real world with all the torque. Short motor is £1100-1300, headgaskets are about £100-120, you need fluids and labour, and then remap the PowerFC and AVC-R. Check your insurance.

 

john is the torque on your car really that much better with the 2.5ltr compared to when you had the td05/06 turbo on the 2 ltr engine

 

Just for you I fired up my laptop and got a representative comparison of the 2.0 and the 2.5, no real difference apart from the 2.5 had headers. Both ran generous NF doses and a 20G.



Dark lines are torque, bright lines are power. Red is 2.5, blue is 2.0.

These are Delta Dash wheel torque and power plots for the 2.0 and the 2.5. The 2.5 doesn't just give 25% extra torque, in the area where you would have very little boost, the 2.5 has already spooled up, differences are about 110-120 lbft at the flywheel at 3000-4000 RPM for example - these runs were done in 3rd gear (UK ratios) so give a representation of lag in an intermediate gear. Feels no laggier than a well sorted TD04 on a 2.0 does. Just a lot "bigger"

 

thats a major difference in torque curve for the 2,5 ltr

 

Then, fitting the Ion running at much lower boost and with no octane boosters it runs the same top end power with much less torque:


Ion - Red, very little boost, low octane, 20G - Blue, lots of boost and octane


And then the Ion wrung out with octane boosters again, which broke the engine:


Ion and 20G compared both running as much as I could make them do. Red - Ion, Blue - 20G. If the engine was tough, you can see that it tolerates the larger turbo quite well in terms of boost threshold.

This could be considered to be over the limit of the EJ257

 

so does that mean that there is no point going for the crawford performance block with forged rods and pistons if using the td05/6 20g then?

my car at the moment is running about 300 bhp so 400 would be a good power increase.

cheers david

 

Simbo, how is that 300 bhp being measured? My car makes ~290 bhp with nothing more than a decat, remap and upped boost. With your mods you should be looking at 350bhp minimum, I'd have thought.

 

On a 20G I wouldn't bother with the built block, on something bigger if you want to use it to its potential I would.

 

300bhp with a td05/06 turbo i find that hard to belive its that low,when i was waiting for my injectors i had a safe map on the car and that had my 440 injectors running 100% duty and that was only 1.2bar

 

well the 298.8bhp was with the topmount on the dastek rollers not got it remapped for the frontmount yet.

cheers david

 

so what would be bigger ,price and would everything else cope?(injectors etc)

 

The iON turbo I mentioned does about 10% more power for similar octane as shown. I don't think there is a proven route to holding the headgaskets down on the EJ257 yet though for going beyond where I have. Would suggest a closed deck 2.2 or 2.33 if going to run silly power. I use 740cc injectors to give more headroom, the 550s were maxxed out a while back when pushing the 20G hard.

 

hi john so say i get the standard sti 2.5 block running with the 20g it should be a good reliable setup then with loads of torque ?

would the head gaskets be a problem with this power?

cheers david

 

I would say yes and yes, but it is still early days on the 2.5. 20 PSI midrange, 18 PSI by 6000 RPM should suit this setup well, and give about 400 BHP/400 lbft on optimax.