Turbo Problem?

[TheRocket300zxtt]

As you can see in my sig, I own a Z32 twin turbo (stock turbos). About a week ago I noticed something strange happening with the turbo's. They would spool up fine in 1st gear, but when I would shift into 2nd gear and accelerate they would spool up for about a second and then slow back down while I have the pedal floored and the car would stop pulling. Like my back isn't glued to the seat. Then in the remaining gears the turbo's feel like they did after they slowed down in 2nd gear, and the car still doesn't seem to pull. I have no idea what it could be. Any idea's would be greatly appreciated.

The only things I can think of are: turbo's are going bad, Leak in the hoses, boost jets, and the absence of a boost controller. Also do I have to reprogram the ECU again after installing downpipes and high flow cats?

Also I have noticed a "tapping" sound coming from the engine bay. It gets faster when I press the throttle. What could this be?

Thanks,-Chris
Modified by TheRocket300zxtt at 9:07 PM 7/29/2005

[nsrZ32]

As you can see in my sig, I own a Z32 twin turbo (stock turbos). About a week ago I noticed something strange happening with the turbo's. They would spool up fine in 1st gear, but when I would shift into 2nd gear and accelerate they would spool up for about a second and then slow back down while I have the pedal floored and the car would stop pulling. Like my back isn't glued to the seat. Then in the remaining gears the turbo's feel like they did after they slowed down in 2nd gear, and the car still doesn't seem to pull. I have no idea what it could be. Any idea's would be greatly appreciated.

The only things I can think of are: turbo's are going bad, Leak in the hoses, boost jets, and the absence of a boost controller. Also do I have to reprogram the ECU again after installing downpipes and high flow cats?

Also I have noticed a "tapping" sound coming from the engine bay. It gets faster when I press the throttle. What could this be?

Thanks,-Chris

Modified by TheRocket300zxtt at 9:07 PM 7/29/2005

1. Your car is probably in safety boost. If you search around on the internet, like on tt.net in tech, there's a write up on it.

2. You don't need to reflash the ecu after doing testpipes and downpipes

3. Tapping is probably the lifters, its a common problem in the Z32's. Running synthetic oil usually helps. Something like royal purple or redline usually takes the sound away then run something like mobil 1

Best of luck.

[TheRocket300zxtt]

Thanks a lot for sharing your knowledge with me.

[TheRocket300zxtt]

I am unable to find the write up on "safety boost." Is there any way that you could tell me how to turn this off? It is really starting to get on my nerves. Also, the car kind of backfires when i release the throttle while still moving. It sounds more like a suction or backpressure. Do you know what this is?

Thanks in advance,-Chris

[nsrZ32]

Here's the safety boost info....

http://www.twinturbo.net/ttnet....html

Here's a tip on how to turn it off....

http://www.twinturbo.net/ttnet....html

Hey atleast tt.net is good for something Tech and FAQ are worth a trip there, beyond that...keep it.

[TheRocket300zxtt]

Thanks. Is it a good idea to take out the boost jets that came with the ECU? I don't have a boost gauge in yet so I have no idea what boost level I am at. JWT says that the boost level should be between 12 to 14 psi. If the boost is greater than 14, which my car may very well be, it says that the car will detonate. Could this be putting the car into safey boost?

Also, I took these jets out last night and took the car for a little drive. It actually felt slower and the turbos didn't seem to spool up very hard. The car didn't seem to go into safety boost, they just never really kicked in. What do these jets do and should I look at getting different ones from JWT?

Thanks,-Chris

[TheRocket300zxtt]

bump

[evildky]

if you remove the boost jets you'll be back down to stock boost levels it won't hurt anything to run less boost

remember the boost jets are a restriction to keep the wastegate actuator from getting the full boost actually made by the turbo thus allowing it to stay closed longer and allowing you to make more boost

[TheRocket300zxtt]

That makes sense. I will have to put them back in. What if I am pushing more than 14 psi of boost though? I guess I will have to wait until I put my boost gauge in....

Thanks a lot!

[TheRocket300zxtt]

I just dynoed the 300zx at Tuner War today and I must say that I am very unhappy with the results. About 2 years ago I dynoed the car when it was stock and it put out about 232 whp and 251 lb/ft of torque (not too bad). Well since then I have added a ton of go fast goodies and unfortunately it hasn't made the car any faster. See for yourself below.I believe the car went into safety boost on the first run (red) at about 3,600 rpm's. I still do not have a boost controller or a boost gauge but I should have the boost gauge on in 2 weeks.
Modified by TheRocket300zxtt at 6:26 PM 8/20/2005

[evildky]

what have you added? and your stock boost gauge not working? or is it an N/A swap? they didn't have a simple gauge and t fitting on hand to moniter boost!? seem like they should have that on hand as a tuning aid or at least to verify what your gauge reads compared to theirs

[TheRocket300zxtt]

Here's what I have added:JWT Single Pop ChargerHKS Hi-Power Cat-Back ExhaustUltimate Z Split Flange DownpipesUltimate Z High-Flow CatsJWT Reprogrammed ECUUnorthodox Racing Underdrive PulleyApollo Racing Front Mount IntercoolerHowe Racing RadiatorTurbo XS Type RFL Bov'sHKS Turbo TimerInjen Intercooler Hard-Pipe Kit

Yes my stock boost gauge is working, but I've heard that they are very inaccurate.

[sdzxdriver]

Check to see if your blowoff valve is holding the boost. It might be leaking under boost which is why you feel a sag in power. The tapping sound, what rpm is it at? Does it only occur during boost?

[TheRocket300zxtt]

No, it occurs all the time, but it gets faster directly porportional to the rpms.

How would I check to see if the BOV is holding boost? It still goes off rather loud upon releasing the throttle. At the "sag" it feels like the turbos almost cut out.

[evildky]

so did the stock boost gauge move at all? is it pegged? it's more acurate than a finger in the air!

[TheRocket300zxtt]

Yeah that's true. The guy that did the dyno said that it stayed at around 12 psi.

[evildky]

so your boost limited @12psi for some reason, either something isn't holding the boost or the boost jets are not sized properly, and "the guy at the dyno said"? you didn't run your own car on the rollers?

[TheRocket300zxtt]

Nope, the dyno guy did the runs. Either something isn't holding boost or the turbo's aren't producing it.

[evildky]

pull the bov's plug the holes, go for a test run, they are not nbeeded, they just relieve stress on the turbo during quick shifts, hit it wide open and lett off slowly once your boost has peakes, and of course you'll need a boost gauge, go get you a $10 ebay speciat that'l read 20 psi, might not be the best but beats guessing once the stocker is pegged, after that if you still aren't boosting put the bov's back in and plug the lines going to your wastgate actuators, it's best to do this kind of thing third gear on abandoned interstate so go at your own risk but with the wastegate actuator line detached and plugged in third gear you can modulate the throttle and allow the boost to climb more slowly and controlled and see if it'll get there, thew old tired stock turbo's could be "coked up and just not capable of making that kind of bost without a rebuild

[TheRocket300zxtt]

Thanks, I will have to try that. Last night I went for another test run and the stock boost gauge was pegged.

[daniela]

hi, i just became a member, i didn't even know this kind of site exist for nissan lovers!. i have nissan 300 zx tt and i would like to ask you some questions about it what i really need to know, i 'm about to buy some stuff for my car on the internet, but i'm not sure what to choose. you did mention that royal purple and redline oil could be better choice than mobil 1, and i was just about to purchase mobil 1 15W-50, and i have some troubles to buy a thermostat from "nismo" 2120-RS50 or regular nissan oe, i just can't decide which one is better solution??. i would appreciate your oppinion and advice.........thank you, i need to know this asap, because i'm buying this stuff right now and i need to take my car to the nissan service very soon and i think my turbos are start to "joking"............

[evildky]

Welcome to NICO!were all a bit too found of Nissans around here

as for your oil I and most people I know run Mobil 1 full synthetic, I used to run toyal purple, price is about the same but mobil 1 is a lot easier to get (walmart, autozone, just about anywhere)

as for the thermostat I recomend using a Nissan thermostat, the NISMO unit I'm sure would be fine if you wanted to use it, as far as I know most people just keep the stock ones

feel free to start a new thread for any future questions and be sure to shop prices with out sponsors you'd be amazed at how much they can save you on NISSAN and aftermarket parts