Downpipe+boost controller = +75hp?

[Ryncub]

Sound Performance in Bloomingdale, IL is in the process of replacing my head gasket, doing a valve job, etc. I asked them to educate me on some relatively inexpensive options to gain some power and performance since things are taken apart anyway.
He suggested an aftermarket intercooler (~$500-$600). That idea didn't sound too appealing to me because he said I'd only gain about 20 hp.
Then he said I could install a different downpipe ( http://www.hksusa.com/products/?id=661 ). That downpipe is $260. I would also want to install a high flow cat so that I could pass emissions without swapping, so that's an extra $150. He said that under normal driving I'd gain ~20hp with that setup. But he suggested adding a boost controller so I could get up to 13psi with my stock turbo. He said they have a nice one for $70 plus $70 for the install. He said it goes in the place of the cigarette lighter (since my cig lighter doesn't work anyway, that'd be a nice touch).
Anyway, he said with this setup and if I had the controller turned on and turbo going at 13psi, I could gain about 75hp.
Does this all sound accurate? If I'm looking at an additional 75hp for $550, that sounds like a pretty good deal to me. Will I do a lot of wear and tear on the engine with this setup though?
My next question... is a boost controller something I can easily install myself? (that'd save me $70) There is really no labor costs to factor into the new downpipe and high flow cat since everything is taken apart already.
I would appreciate any advice!
Thanks,
Ryan
1987 Supra Turbo

[damone]

Dont bother with the intercooler, the stocker is fine!

As for a downpipe, go with a becauseican downpipe
http://www.bicperformance.com/
His name is randy, excellant guy to do business with.. And a new downpipe will probably make the most difference out of any mod you do..

You can pick up a manual boost controller on e-bay for about $10, (ball and spring type) and install it yourself in about 10 minutes.. The only downside is you haveto adjust boost pressure from under the hood.. which isnt a big deal, set it at what you want, and leave it there..

DO NOT use a boost controller without getting an aftermarket boost gauge first.. and You cant boost no more than about 12psi on the stock fuel system or you'l hit fuel cut..

[Jeeves]

Ummm, not really....

The stock intercooler is crap. Fine for stock levels, but anything past that it sucks. It has a horrendous pressure loss across it, and it doesn't have the best cooling potential ever for that matter. An upgraded intercooler + hardpipes is a fantastic upgrade. The hardpipes are equally important.

A downpipe in this case will help as long as it replaces the stock elbow with a 3", free flowing one instead. Not to mention the exhaust system behind it. If it's restrictive you won't get near 20hp out of that.

A Manual boost controller, like damone said, can be had for cheap, is simple to operate and doesn't cost jack (maybe some rubber hose) for install. He also has valid points about the boost gauge and the stock 12psi fuel cut.

[Ryncub]

If I leave the downpipe, cat, exhaust, etc. stock and just put a manual boost controller and new guage in... can I expect a decent amount of horsepower increase? Like I said before I'm looking to get a little more power out of the car and not spend a whole lot of money right now. I'm assuming everything would run like it always has until the boost gets in the 8psi-12psi range. What kind of horsepower increase can I expect?
The downpipe, elbow, cat sounds great, but I think I'll hold off until I have the head gasket and valve job paid for.
Also, with the high flow exhaust, downpipe, etc. will I only feel the difference in performance when I'm running HIGH RPM's? I'm just guessing that the stock has ample flow in normal driving RPM ranges, but when you get up above 4k-5k is that when the stock limits the power? Just a guess.
Thanks

[bgrieger]

Without doing the exhaust, you'll notice a pickup in power that will make you grin, but nothing earth shattering. You'll start to run into boost tailing off at higher RPM with only a couple of lbs extra boost. The exhaust system restricts the gasses mroe and more the higher the RPM goes. The turbo spools up fine, and holds 10 lbs until 5000, then it will fall back to about 8psi.

For high end power only? No. You'll notice the downpipe and exhaust through the mid range from 3500-5000 the most.

For cheapies on the upgrades, look on ebay for a Megan Racing downpipe. It is a clone of the HKS one you posted, and comes in at under $100 to your door. I purchased one for breaking in my new motor (front cat was toast) and I was really surprised at the quality...I tend to be very anal about build quality when I have to pay for parts...Perfect polish, flanges fit well, machine tig welded stainless, gaskets included as well as new bolts, washers and factory style locking nuts. Really a sharp looking unit. Sure it's got the small neck to match the stock elbow, but it does the job. Guys were pushing 400hp on that design long before the full 3" setups came about...You can get a cheap 3" generic cat and have an exhaust shop make you something for the back half with a muffler of your choice. Add a K&N drop in replacement filter to the stock air box and it should come in sub $500 for everything. Then worry about the intercooler and the hardpipes etc. Personally, the pipes would be last on my list. There is no power to be gained from them, but some additional boost stability (rubber flexes and "bounces", and can create very mild surges from time to time) and reliability.

Just another opinion...

Bob

[Jeeves]

The 7M's were not notorious for their low end power either. :-/

[bgrieger]

Sure they wereknown for low end power...just that it takes a little more than they made to push our piggies happily from the line...MKII guys that swap to them never complain about the low end

[Jeeves]

Bah. Turbocharged cars rarely have low end and the 7M's not an exception

[damone]

I would compare the off the line acceleration of my car (when it was stock) to that of a poorly running Chevette.. I coudlnt spin those tires if my life depended on it..

But, the first mod I did to my car was homemade hardpipes, manual boost controller and boost gauge.. I didnt notice a whole lot of difference.. not enough to make me grin anyway..
The becauseican downpipe will replace the turbo elbow (most restrictive part of exhaust) and the pre-cat.. its not so much a horsepower adder, but it helps the turbo spool a lot faster..

[Supraracer]

My god. ok the stock intercooler is fine for under 400rwhp, hell most SR20 guys use ours as an upgrade. the most power ive heard through the stock intercooler was 540RWHP, when he upgraded to a FMIC, true he gained like 40-45 hp but the stocker is fine, you can stick with it for now.

just a 3" Dp is a HUGE gain even without the 3" elbow, but you must have a 3" caback exhaust for it to work otherwise you can dammage the turbo or possibly blow a headgasket from backpressure. the 3" Dp acts like a big air canister and builds pressure inside that puts excessive stress on the turbo, and if you boost too high can back feed into the combustion chamber and if you have the old factory HG it can blow it out.

intercooler hardpipes helps tons in throttle response and boost efficeincy. not to mention that you run the risk of blowing off the brittle hardened rubber pipes if you run above 10lbs.

an intake doesnt help too much stock but once you upgrade to a free flowing exhaust and higher boost levels this is a Very big mod. trying to boost much more than the stock 6-7lbs through the stock filter is a joke. the more you boost the more power it hinders.

honestly with an intake and on stock motor/exhaust you can do 9lbs reletively safely depending on how well and how old your motor is. i would recommend you get the 3" Dp, 3" catback, and a K&N cone filter and a MBC and run 9-10lbs. that will put you in the mid to low 14's depending on how well you drive and if its an auto or a 5spd. a huge noticabl differance and youll wonder how you drove it before.