The peak boost I make is not very consistant sometimes. Some nights all I can get is .35-.36 bar and other nights I get .39 bar. Boost is not droping off like a boost leak it just does not peak the same. This is doing the same type of 2nd and 3rd gear pulls. Is this an issue or normal?

 

are the air temps on the nights simaler cause i know that can alter the peaks alittle

 

other than the wastegate spring, what are you using to control the boost?

 

air temp is key... with only a WG spring set @ 6 psi, I saw 8-9 PSI on cold days.

 

I would assume its a temperature difference. It could also be your exhaust, with my 2.5" catback I cant get above 5 psi really, but with the 3" cutout open I can get about 6-7 psi.

 

What type of WG?

Slimer- Yes, just per my tial WG

i thought about temperature and there has been a difference, but no more than 15 degrees.

Right after the install I ran an open downpipe for a couple days and saw .39-.4 all the time, have never seen .4 since the cat back was connected.

 

probably a couple factors contributing...
the boost gauge that is built into your blitz turbo timer probably isn't the most accurate.
Controlling boost with just a WG spring allows a little float
Air temps will always play a role
the diff btween 5.2 and 5.7 psi isn't really significant.


Just let me send you some injectors and you won't have to worry about it. =)

 

All the above mentioned will play a role, but I think the cat back is the biggest factor.

 

Sorry for the slight off topic Mike. Brad, did you ever run your car with an open cutout while still all motor? I am curious how much quieter the exhaust is with your turbo setup as compared to an all motor setup.

I know some Grand Nationals are quiet while wizzing down the track and I find out that they had their cutout open. Then you let me open my cutout and it's insanely loud!

 

OT reply: I didnt actually drive this car, however I did start it with just the y-pipe, and I drove my VG max with just a y-pipe around the block. I do know that the VG was unbearably loud, almost embarassing with that loud of an exhaust. Now with the turbo and it open, I have no problem driving around with it open. Granted, its pretty damn hard to carry on a conversation inside the car, and I'm sure its loud enough for a ticket, it isn't deafening. It's kind of hard to describe, but I guess it could be compared to a small V8. I can get under the car with it running and not have to cover my ears. Sorry for the long-winded not-so-direct description. I'll try and get a sound clip sometime.

 

Like everyone else is saying, with just the WG spring, you'll see variance. On my wife's Integra, the Deltagate II allows anywhere from 5-7 psi on a 5psi spring. On my Tial, boost fluctuates from 6-7 psi.

Also, you have to factor in engine load. If you're going uphill in high gear, you may experience some boost creep. On the dyno, my car makes 7psi in 3rd gear (auto) every time. But at the track, I never saw more than 5 psi in both 1st and 2nd, and then about 6psi in 3rd when I hit the 1/4.

And I saw that you're not making as much boost w/ the cat, this is totally normal. When I first did the turbo, I had the stock cat on and only saw 5.5psi on a 7psi spring. Put 3" test pipe in, and boost hit 7psi.

 

Never had a cat on the car with the turbo. 3" test pipe to my 2.5" Greddy SP. I first ran with just the open down pipe, then later connected the test pipe and cat-back.

 

deltagate.....

 

yeah on cold days they seem to spike some. Im set for 10psi and on cold day in 5th i may see as much as 13.5psi

 

Hmmm, most of you guys somtimes get boost above your wastegate spring size or above your electronic boost controller settings. I have never ever gotten anything above my .4 bar spring

 

So are you saying your better than us?

 

I think that is a given

 

we all know turbo i30's are better

 

I didn't know this was occurring ever since you got the exhaust connected. Primary culprit is the exhaust. Its well documented that people often gain a half psi to 1 psi, sometimes even more by simply switching to a more free flowing exhaust. You did the opposite and that's why you are seeing the difference. He's using a tial wastegate btw not a deltagate, or were you saying he should get a deltagate to induce boost creep and get his lost power back lol. Another factor could be engine load (based upon the gear you are in). I routinely see more boost in each successive gear because of more load on the engine. First gear I don't see more than about 8psi, 2nd gear 10 or so, and 3rd,4th,5th usually goes something like 13.5, 14, 14.5.

 

OMG, I thought my wastegate was starting to creep already. But that happened to me too. With the stock exhaust, my max pressure was about .36 bars. With the bigger exhaust, Im at a constent .55. I hit .6 the other night when it was misty. So air temp definately is a factor. But then again, my down pipe is leaking so ...