How much horsepower does each pound of boost make on a stock turbo

 

agghh.. that question is impossible to answer as every car is different.. get it dyno'ed.

 

in general 1 atmosphere or 14.7 psi will increase the car's output by 100%. So in a perfect world a car that makes 100 hp NA will make 200 hp with 14.7 psi.

 

It's usually 10hp per pound, but that depends on the car, the mods, and the efficiency of the turbo.

 

well as long as u dont run out of octane

 

That's cool. That means I may have gained as much as 80hp just fixing my boost problem with a mbc. I was running 11psi for almost 3 months without knowing it. Now I'm at 20.5psi. Talk about bang for the buck for me!!!

 

Actually, yes, you probably did.

Btw, how could you not know you were running 11psi for 3 months? Don't you have a boost gauge?

 

I didn't at the time because my service manager actually told me it would void my warranty!! I said screw it finally. Then the guy who installed the gauge said "Yep, perfect 11psi...I've never seen a 4-banger do that!" I was like, dude wtf?? Im supposed to be hitting much higher. So took it to Topspeed and you know they figured it out in like 1 minute. That's my story! It's been awesome ever since

 

MMmm, k, so the service manager said a boost gauge, which is a safety monitoring device, would void your warranty, but he didn't say anything about your MBC, which can blow the engine if used improperly? Sounds fishy. Regardless, glad you finally got a boost gauge and saw what was happening. I'm amazed at how many people buy used Evos and don't realize they are running around with 11psi. It happens all the time...and they buy the thing without even realizing how slow it is, haha.

 

Yeah...I bought it used, had it serviced at Mitsu under warranty, and the Service Manager said ANY mod will void my warranty there. This included even a boost gauge or turbo timer! I was shocked. I asked about a boost controller after that, and of course, he said no mods at all. Yeah, it sucks for people like me with the 11psi problem. It should be a sticky for new used Evo owners. What really sucked for me was that Mitsu told me my car was completely stock and running perfect. When in reality it was hitting 11psi, had 272's in it, and an upgraded clutch. What dumbasses! I have been going to Dyno4Mance now for all maitenance.

 

So you didn't have an MBC problem, then, but you fixed the problem by installing an MBC. I thought you originally said you had an MBC problem that was causing 11psi. Basically, you got a used Evo that used to have an MBC, then when the original owner put it back to stock, he didn't properly re-install the stock boost system. He probably used plain vaccuum hoses without the restrictor pills.

Glad you're fixed now. Didn't you say TopSpeed fixed you?

 

No, the MBC fixed my problem. The problem was the previous owner did not put back stock boost lines on. I could have fixed my problem with stock boost lines, but after all that with Mitsu, I said screw them.

 

You beat me to it! Yeah , Doug at Topspeed fixed it. They are awesome. So is Dyno4mance, which is only 30 minutes away.

 

This is true, although I believe once your boost gets so high you will not see as great of gains. For instants changing your boost from 20 to 24 pounds wont get you 40 hp.

 

Changing from 20-24 on the stock can very well give 40whp. I know, because I've done it and proven at the track. You can prove it on a dyno, too.

However, you're just repeating what I said in the quote: IT DEPENDS ON THE EFFICIENCY OF THE TURBO. I already made that point. From 20-24psi, we can gain 40whp, but from 24-28psi, we can't.