tt300z

Ok I Just Want To Know If Anyone Knows How Many Pounds Of Boost A 91 Tt 300zx Runs Stock...i Want To Know Because Mine Is Only Reading At 4 Pounds So I Think I Might Have A Boost Leak Somewhere Cuz I Dont Think They Are Suppose To Be So Low...if Anyone Has Any Suggestions Please Let Me Know Because I Want To Get This Fixed Asap

emo236

8.5 to 9 psi. 7 psi is safety boost. Stock boost gauges aren't very reliable...remember that.

tt300z

Yeah i know..I have an aftermarket boost controller but it is only reading 4 or 5 psi

tt300z

Thanks for the help...oh also do you know at what RPM's each turbo kicks in (1st and 2nd)?

91zxtt

4-5 psi is real low. The 1st place I'd check for a leak would be around the black hoses attached to the front of the trottle bodies. These things get brittle and crack. When did you 1st notice the low boost? Was it gradual, or did it happen al of a sudden? Have you noticed a serious drop in horsepower?


My turbo's hit hard at about 3000 RPM's.

emo236

check boost leaks and also leaking turbos. check foir oil leaking or smoking turbos.

tt300z

well it was like over time it decreased in boost and yes there is a serious loss in horsepower...

91zxtt

When you mat the throttle on the freeway do you see smoke out the tailpipe? If so, it could be your turbos. If smoke comes out the right side, then its the left turbo and vice versa. Does the turbo whine appear to be any louder than when you had peak boost? If so, it could be the turbos. Otherwise, I'd check all of the tubing between the turbos and the throttle bodies. Check the 4 hose clamps on the black hoses leading into the TB's. If they're loose, then tighten them. If not, take the hoses off and inspect them for cracks. Since it's gradual, then I'm guessing you have a hose that's worked itself loose, but it could be a turbo also. I'm trying to be optimistic. Let us know what you find out.

tt300z

ok well there is no smoke so i think it might just be a hose like you said so i will check that out and get back to you..Thanks for all your help...I dont know alot about nissan's or turbo's at that, so i appreciate the help

tt300z

oh also do you know when each turbo kicks in? I was just wondering you know, I just want to know for my personal info...thanks

emo236

same time...around 3K rpm.

emo236

Also, as a word of advice. I suggest you start visiting the forum often and reading liek crazy. Owning a TT isn't neccesarily easy. you'll learn to want to have the knowledge of nissans and most of all turbos.

91zxtt

That's good advice.

tt300z

ok well check this out i was driving today and i look over at my boost gauge and it was boosting at 8 or 9 for just a few minutes then i stopped at the stop sign then i took off again and looked at the gauge again and it went back up to 8 and then dropped back down to 5 and my gas pedal was floored the whole time so it was really weird..so does that sound like i have a loose hose or a hole in a hose somewhere or what should i do?

91zxtt

I'd say loose hose. If it was the turbo, then it wouldn't be intermittent. I had the same thing happen once after I cleaned the throttle bodies. I didn't tighten the hoses enough, so when I hit 8-9 psi of boost, it would bleed down to almost nothing. 5 minutes and a screwdriver did the trick. You could have a hose lose, or split near the intercoolers also.

tt300z

ok well in a way I got the boost prob. fixed..I got a boost controller and when the guy was installing it he said he found three boost leaks (hoses ect.) well he fixed two of them but he couldn't get the other one..and since all i payed him for was instal on the boost controller it really wasn't his job to fix it but yeah so now i am boosting around 7-10 psi but the boost controller is cranked all the way up..so thanks alot for helping me the info you all gave me was right and very helpful...

emo236

get that other boost leak fixed! it shouldn't be too hard, just getting in there. but enjoy 15 lbs pretty soon.

tt300z

haha cool thanks alot!