MaximumHP put this together. His latest dyno run vs mine. Both cars at about 5psi. I do have a 3" down pipe, 3" test pipe, and 2.5" cat back compared to his y-pipe only. But besides that they are very similar as in stock manifold, same boost, etc...

 

which is which?

 

 

Jeez, rub it in why don't ya?

Anyway, congrats on the successful install. You're making almost as much torque at 5 psi peak boost as I am at 12 psi peak boost.

 

Hows about getting a 3" exhaust?

 

why does the turbo add more horses w/ the same amount of boost?

 

SC runs off the belt, turbo, off waste.

I'm willing to bet that the majority of the power is due to the turbo flowing more air.

In other words, 12 psi on a t28 isn't flowing anything near what 12 psi on a t04 will.

 

The SC isn't hitting 5psi till redline. The turbo hits full boost before 4000rpm. That and there isn't the parasitic loss from the belt drive on the turbo. 3" Exhaust doesn't hurt either. We gained 2psi and 50whp w/ the 3" and a test pipe.

 

heheheheh

Hey, I did not put that together just passing it along

 

yeah i guess it takes a bit of horsepower to run a supercharger. do you think once that turbo spools up that it is actually assisting the exhaust flow? probaly not but i guess it just doesnt restrict exhaust as much as you would think. sucker flows good man!

 

BUT what IF....you had a supercharger w/ bypassed AC? Would that give a good bit of power back into the blower? (adding a pulley ~minus 20hp)...but taking another one away thats a lot bigger...wouldnt that show improvement?

 

It might give a bit more power per lb of boost, but the fact still remains that it won't show full boost till redline and that is 90% of the power difference between the SC avaiable for our cars and a turbo

 

3 inch test pipe on a turbo car, that junk kills your low end torque!!! I reinstalled my 3 inch cat.

 

The 200ft-lb to the wheels Shadow's car made at 3k says otherwise. That and the extra 114ft-lbs it makes before 5k. Then again it could have shown just how crappy the old 2.5" crush bent exhaust actually was.

 

You want as little exhaust restriction as possible. That's why some guys just run a downpipe and nothing else...

 

Well it makes sense and Mishap has it right. You have to consider the TYPE of SC used. If one used an Eaton, Whipple or some other low rpm torque SC, the numbers might be different?

 

Out of all the "bigger is better" mentality that normaly is wrong about car parts the down pipe is the exception. The bigger there the better and it will help power all through the power curve. Several feet after the turbo you can start to narrow the pipe to fit under the car if needed but exhaust restriction should always be kept to a minimum..
~Scott

 

Your wrong there sparky

 

Wasnt me (Bijan) who posted it

 

Then who did?? It's your name isn't it???

 

AC should have no noticable effect on perfromance - magnetic clutch disengages compressor when AC is off, as well as past 3/4 throttle whe A/C is on, so you're just spinning a fairly light pulley with no resistance.

You are carrying ~50lbs of A/C stuff around ,though. Broaner ripped his out. I could compensate for that weight by throwing out my spare tire and jack, cleaning 20lbs of McDonalds garbage from back seat, and going on a diet to lose 10lbs. But I won't.

 

I never really understoof the whole removing AC thing, unless you we doing some really hardcore racing with a lot of money on the line, it isnt going to even make a noticable difference if thats the only weight reduction you do.

As mhadford said, if you dont have it on, its free-wheeling on a next to nothing resistant pulley.

Youll be happy you have it when summer hits, in GA

 

Not having AC sucks... my last car didn't have AC because I never got it recharged after hitting a deer, and my turbo car doesn't have it either. Going to suck in the summer. I'm worried that the AC in my beater isn't working either.

 

Having no AC rocks! It may be free wheeling but it still has intertia. Having no power steering also rocks! I'm hoping these two will help me get to 300 wheel on the 3.3. One super short belt... soon to be a bit longer.

I did it for many more reasons besides the power. Cleanliness of engine bay, weight saving, throttle response, gas mileage, money(I sold it.)

 

w/ what other boost mods?

 

inertia isnt causing the crankshaft to waste any more power on it than it would if it werent there. The real killer of an A/C is having it turned on while trying to race, and it cycles on and off so much to prevent evaporator freeze-up you dont know when its actually taking away crankshaft power. The crankshaft is already spinning, and a belt with no resistance isnt going to rob HP.

 

Nice comparison Mike. you should sell your 2.5" cat back and get a 3" - bigger is always better with boost - you don't have to worry about that scavaging effect crap.

The difference is the inherant effeciencies of the turbo and SC. The best SC's are about 50% effecient. Mike T04 at 5psi is about 73% (can't remeber mikes exact compressor trim).

BTW Mike, when you start running more boost things will just get better. That big ol compressor isn't designed to run low boost like you are. Between 9 and 22 psi you will be hitting 78% effeciency =)

 

couldn't say it any better than that, the throttle response was the first thing I noticed, just amazing! when I took off PS and AC.

 

The car will simply suck to drive w/o PS.....

 

not if you only drive strait!

 

3" super short exhaust, Custom lightened OEM diameter crank pulley(No power steering ribs) custom tensioning setup(maybe), ported OEM TB, 3" charge pipe, open inlet or CAI(can't decide).

The belt does create resistance. There is friction and inertia.

No it doesn't. At 30 its totally fine. I can turn just fine at 30+. Breaking the tires loose while turning is no problem at those speeds. At 70 its much better than stock. Plus it'll bulk you up. Also, with a much lighter car it isn't an issue. I haven't weighed since the swap but my estimates say I'm 250lbs lighter than stock and will be 350 by the end of the summer. If it does prove to be annoying I'm going to do a hybrid steering rack out of something else with a higher ratio. Really it doesn't need much though because 50-150 is so much better than stock now. Going to a higher ratio will decrease the highway stiffness but increase low speed agility. There pretty much nothing in my engine bay but engine, tranny and battery. Finally, I'm changing to a properly size tire on my next set(235/45). The OD of the 245/45/17 is larger than stock. Bad for gearing...

 

He's not talking about driving at speed hes talking about parking, trying to pull out of driveways, etc. Everyone knows that driving at speed without PS isn't an issue. Mike's driven my car so he knows exactly what hes saying. Anything over 10mph isn't bad, but when you have to crank the wheel from one side to the other to pull into or out of a parking space its miserable, even with relatively skinny 215s on it. With the 195 snows it wasn't that bad, but I can't imagine what my 245-45 stickies are going to feel like.

 

Hell yea Broana.....youre on your way! Good luck w/ everything