Supra lacks power.

[Guest Poopra1]

I recently imported a 95 RZ 6 speed supra and it felt really slow, like 180hp slow.

I raced a buddy's stock 2015 SI civic to confirm and his 200 hp destroyed me so this solidified my suspicion that something is wrong with the car. I don't have a boost gauge but im pretty sure the car is not holding boost.

I can hear the turbos spooling but there is a constant hiss that comes along with it which means a leak somewhere in the pressure side. I have done a boost leak test but it didn't bring me to any conclusions. I found a really great sticky on this forum explaining the sequential system and how to trouble shoot it, so i started testing VSV's and i think i may have found my problem. The resistance i get on across the Intake Air Control Valve (IACV) VSV is 44 ohms which i read was supposed to be like 22 to 26.

Also when I blow gently into the port that is closest to the plug i hear air passing through what looks like a vent opposite the side of the plug the vacuum ports are on. There is no way im putting anywhere near 10psi of pressure through the VSV so im thinking something may be shot. I also noticed that the valve cover right beside the actuator connected to this VSV is quite dirty while the rest of it is clean which makes me again think that this VSV is leaking.

 

Should air at low pressure be able to leave this VSV?

Any suggestions would be appreciated, i will continue to trouble shoot the car until i find the issue.

 

Any info would be greatly appreciated.

 

I posted this on another forum and the guys over there suggested i do spark plugs/oil change/exhaust/intake/downpipe/dyno it/ boost controller/ essentially mod a broken car. I wont be back to that forum again as this one seems to have many more technical articles and the population also seem to be confident in working on there own Supras rather than dropping them off at a shop to have them built.

Edited September 6, 2015 by Poopra1 (see edit history)

[Guest Poopra1]

here is a ghetto paint drawing of what im trying to describe.

[ScottC]

it sounds like you are on the right track. Try putting the car in TTC mode using this guide.

[Guest Poopra1]

I think there was a difference in TTC mode but it was hard to tell.. I have decided to replace all of my vacuum lines some look to be in rough shape.. Hopefully that does the trick.

[ScottC]

after taking the car out you should find both actuators in the open position and remain open. If they are closed I would leave it in TTC mode while you check for leaks, once the system pressurises reconnect the vsv's one at a time.

[Guest Poopra1]

I found the problem.

Thank you so much for the tips and suggestions! I changed most of the vacuum lines and did another boost leak test...i noticed the intake held pressure but the system in front of the throttle body to the air inlet/turbos did not. I did another leak test from the intake of the turbos to the throttle body and i couldn't hear anything obvious but i noticed it definitely wasn't holding pressure...then i found it. The bottom of the pipe that leaves the throttle body and does a 90 degree turn down was barley connected to the rest of the intake system. I pulled the battery re fitted the pipe and took it for a drive. The car pulled the way it is suppose to.

 

Thanks again for the tips!