Need more power at same boost

[vagen]

As many here know I am autocrossing my RX. I have a pretty fresh engine that has had a JWX rebuild and tuning. I have taken this engine a bit further with an intercooler boost control (set to 11psi) and a CAI. I am now looking for more power without turning up the boost any more. Any help is appreciated.

 

I am not ready to do an ej swap yet.

[GeneralDisorder]

For more power you need more fuel and more air. You are already forcing the air into the engine at higher than atmospheric pressure with the turbo and so if you want more of it you have two options - increase the pressure, or increase the volume. Since increasing the pressure is out of the question for this engine you need to determine where your bottleneck for volume is located (if there is one). Ports, valves, or the CFM of the compressor wheel on the turbo - a larger turbo will flow higher CFM at the same pressure. But it may be that you are already approaching the volumetric efficiency of the engine and thus the only way to increase the volume would be to increase the displacment.

 

I suspect that if you want more power you will end up needing higher boost. We all know that it's a mistake to do this with a stock engine so if you want that you will need to o-ring the block, replace the head bolts with studs, and change out the pistons. With careful management you could probably see 175 HP or a bit more. But the cost is high for that type of custom work and you may not get it right the first time around.

 

That's why you see so many people doing EJ swaps. A non-turbo EJ22 with 200k on it will handle 5 psi all day long and twice on Sundays making 200 HP. You can pick them up under any rock for the price of dinner at a nice steakhouse.

 

GD

[vagen]

Here is the short list of what I haven't changed.

Intake manifold, exhaust manifold, turbo, camshafts, ecu, injectors and turbo.

 

I have on the shelf a decent size FMIC and I can get a header that will fit a td04. I know a larger turbo would mean cooler charge temps so that is high on the list.

[presslab]

I'd say go with the TD04 and equal length exhaust header. At 11 PSI the VF7 is blowing some pretty hot air.

 

You're pushing it with a stock fuel system, even with your current setup.

[vagen]

I do plan to swap the stock injectors for 280zx-t injectors along with the appropriate maf mod.

 

The reason I am looking for power is I am being beaten by a civic in street modified.

[john in KY]

Dump the stock exhaust after the turbo except for the flange that bolts to the turbo. 2 !/4 inch exhaust all the way back from the turbo does make a difference and fits the original exhaust flange perfectly. Ran 12 pounds of boost for 5 years/almost 100k miles in my old turbo wagon with a few modifications and never had a lick of problem with the set up.

[vagen]

I am running a TWE 2.5inch bellmouth DP with 2.5 exhaust from there back. I found my missing HP I had turned the boost down to 9psi for some reason I think it was the clutch so there's my missing power. I will still work on more

[AWD TURBO!]

Edited February 23, 2010 by AWD TURBO!

[twilightprotege]

dont look for more power, look for a better power to weight ratio - remove dead weight in the car. get better tires and suspension.

 

if you need more power, cams are an easy solution for a turbo engine. you'll probably end up making more power at lower boost. increase the boost back up and it's a double win.

 

and then the final solution - practice.

[vagen]

dont look for more power, look for a better power to weight ratio - remove dead weight in the car. get better tires and suspension.

 

 

this car is stripped out the only interior is the required front seats. even the sound deadening is gone

[twilightprotege]

tops.

 

well then spend money on the suspension and tires. from simple street tires to semi slicks, a friend of mine dropped 2 seconds per lap off a 63 second lap time at a track near me. through practice, that time dropped another 1.5 seconds. that's a huge drop through something pretty simple really - and no increase in power.

[Caboobaroo]

You need suspension upgrades. Go with a 5-lug setup using Impreza parts in the front (minus the lower control arms and outer tie rod ends from an XT6) and upgrade to some KYB AGXs and different springs. Or go coilovers from a Legacy GT '05 and newer. You can then also upgrade the brakes for more effective braking as well.

 

My RX, I'm currently running a complete 5-lug conversion, KYB AGXs up front with the cheap ebay coilover sleeves, stock shocks in the rear with same sleeves and a XT6 front swaybar. I have custom alignment specs which I set the car to (I'm a alignment specialist) for handling purposes and this car with this setup, handles just the same as my friend's '05 STi with Cobb front and rear sways and endlinks, Tein Flex coilovers and an anti-roll kit up front for steering geometry.

 

I've done EA82T modding and my last setup which lasted 200 miles was a rebuilt EA82 SPFI shortblock with new rings and bearings, rebuilt, ported and polished gen 3 turbo heads with Delta 260 cams (first set made by Delta, got them from WJM), '88 XT N/A spider intake modified for the turbo setup, Nissan 280ZX turbo injectors, rising rate fuel pressure regulator, custom header, TD04 turbo, Megan Racing 3" bellmouth downpipe straight to a dump in front of the rear axle, Samco intercooler hoses, WRX TMIC, AEM cold air intake modified to work on an EA82, Greddy turbo timer and a Greddy Profec II B-Spec electronic boost controller. At 7200 feet above sea level, I was running a steady 12psi. Would I build another EA82T? maybe if I had enough money and time to throw at it to work all the bugs out as far as cooling and stability for running higher boost.

[vagen]

I am currently running full coil overs on re-valved stock shocks (heavier oil in stock shock) full XT6 sways front and rear on toyo RA1 Dot race tires. I am planning to convert to 5 lug so I can get wider wheels and more travel at race ride height. I'm looking at a set of 15x8 0 offset Rotas.