I was thinking if turbo lag can be improved upon if we use intercooler piping that is smaller in diameter as compare to what we normally used?

Smaller diameter piping=smaller overall internal volume=smaller volume of air to move=faster air velocity=lower turbo lag.... is this logical?

 

I don't think it would be worth the loss in horsepower you will have after you install smaller piping!

 

If the exhaust is able to extract the hot air out from the system fast enough, wont that be okay? by smaller diameter piping, I dont mean small.. just maybe 0.5 smaller...

 

Smaller piping will limit your top-end horsepower once the air is flowing. In smaller displacement turbocharged four-cylinders, you can't always have completely lag-free power delivery and crazy top-end horsepower. Sure, the new 2.0-liter I-4 made by VW/Audi is virtually lagless and has peak torque at 1750 rpms or so up until 4000 rpm (if I remember correctly), but its top end isn't particularly awe-inspiring. Besides, the turbo lag isn't even really bad in an Evo. Drive any stock 2.0-liter WRX and experience lag.

 

I kinda enjoy turbo lag, it's part of the experience of buying a turbo car. If you really despise lag then it's best to get a V8 or an STI. I would imagine a 2.3 or 2.4 stroker helps as well.

 

Very logical and one of the reasons why I am a little skeptical about the use of larger intercoolers. [although some dyno plots look promising]

The smaller piping will improve the transient response for the reasons you mentioned. The thing is that this benefit is off set by its steady state disadvantages - namely pressure loss at high flow rates. I'd go as far as saying that in NA engines, too large an exhaust loses low end torque because of this. I may be wrong.

I think the stock is sized for fairly agressive road use. I don't think Mitsu would let a restrictive i/c pipe be the cause of loss of precious hp. Having said that, there seems to be a bit on the lower i/c pipe where it just necks down to fairly small.

Btw, I believe the same thing happens with intercoolers. Larger i/c internal volume = more lag but the obvious perks. If the air doesn't stay in it for long enough, you won't cool enough etc...

 

Try upgradeing the O2 houseing before you do all that.

 

An O2 housing will improve the turbo response.

As for the IC pipings...my personal experience with the Helix 60mm pipe is a better throttle response. I can't speak for other bigger pipings because I don't have any personal experience with them. However, if you are using the stock turbo...60mm will be more than sufficent. I think anything bigger will only decrease the air flow velocity.

thanks,
Tom

 

I know that works offer a 3" o2 housing. is their dimension ID or OD? if OD does anyone know the ID of the outlet?

Mike

 

Smaller manifold will result in less lag. Dont know about smaller intercooler pipes, but why not just use no intercooler if your going to go that route...

 

Right on.

 

I don't know how smaller diameter IC pipes would make a difference since turbo response is based off of exhaust gases and back pressure. Like Tom said, O2 housing will help, but you could also increase timing on the low end which helps the spool up big time...

 

Increase the exhaust gas velocity (heat wrap or heat coating). Do the manifold, turbo, hotside, o2, downpipe...

Also throw in a longer duration exhaust cam.

 

This is what I did with my evo....to reduce turbo lag...I installed a test pipe also a new dump pipe(o2 housing) lighter pulley, upgraded downpipe, intake.....I have a stock hotside 10.5 turbo that puppy spool right at 2600

 

if you introduce more restriction in the system it may not boost as quickly... going smalle rhtan stock is gonna hurt you... mitsu doe snot want a slower spooling car than they have to, so they already tried to work out the spool issues without getting cost intensive and fitment conflicting.