Major Lag!

[s13kris]

Hey guys i hope someone on here can help me.I went to get my car tuned for the first time yesterday and came across a big problem, it seems to be that turbo is lagging by about 1500rpm. The turbo is the PU Highflow by hypergear using op6 rear housing.

now my tuner and i went through absolutley everything that can cause this problem and he found a couple of minor leaks which were immediatley fixed but made no diffrence.

The things that were checked are intercooler piping, vacum lines, BOV(was also blocked off to make sure), boost controller etc.

also the tuner suggested after 5/6hrs of trying and fault finding that the wastgate flap or whatever its called may not be completley closed on idle which i checked earlier tonight after taking off the dump pipe... would i have to turn car on and check on idle or would it be the same as the car being off?

btw the car is r33 gtst

Tuner is very compitent and has a great rep.I am more than happy with the effort that he put in to try find the problem but still the problem remains does anyone have any ideas?

My knowledge is basic so any advice or anything that can point me in the right direction would be appreciated.

Kris

[turboedsloth]

It doesnt start making boost til 1500rpm or it makes full boost 1500rpm later than it did when standard? Cos someone correct me if i'm wrong, but a highflowed turbo will make boost a tad bit later than standard

[PM-R33]

I'm assuming you mean it is making peak boost around 1500rpm later than what it should?

If there was any problem with the wastegate you would see it on the boost plot.

If the wastegate is not holding shut properly your boost curve will be lazy. Something that can easily be seen during a dyno run on a graph.

For the best boost response possible get the tuner to disconnect the hose from the actuator (and plug it up) and ramp the car up very carefully to see how quickly it ramps onto boost. Obviously you will have to back off as soon as your targer boost is reached as the car will have absolutely no boost control and will simply keep climbing in boost.

Compare that boost plot to the one it normally runs and see if there is a large difference. There will be a slight difference but it should not be huge.

[GTScotT]

What wastegate actuator are you using?

If you are using the standard one please have hypergear send you a high pressure item.. The stock actuator wont be strong enough for that application.

If Stao supplied you with a high pressure actuator, follow his instructions on pg 67 of his thread on how to check the preload on the actuator.

The actuator should need to be pulled really hard to make it slip over the actual flap lever. I believe it needs to be half its diameter (the hole) shorter than an easy slip on.. I believe adjusting it a little tighter than that wouldnt hurt either.

[Lithium]

When is it actually making full boost?

[s13kris]

thanks for the response guys. its making full boost at close to 6k when it should be making it around 4200 and im currently using his high pressure actuator.

[GTScotT]

Check your actuators preload and maybe even add a little.

Keep trying to troubleshoot the issue, if it ends up being the turbo I am sure Stao will come to the party.

As for whats next, what dump pipe are you using and have you tried to drop the exhaust before the cat and see if that helps?

How was the car running before the turbo went on? And what else is done to the car...

[hypergear]

I spoken to trent yesterday about it. Its a OP6 rear ended KAI high flow, so the wastegate assembly is factory, unless the disc burnt off or some thing it shouldn't do that.

It really sounds like the VCT controller, unplug it and see if that makes any differences, if not then some thing's gone funny with it. Also check cam timing and etc are all in right places.

[s13kris]

Thanks Tao i will check that, last thing i want to do is jump to conclusions or point fingers so i definetley will get that checked out but also before the turbo was changed car was boosting as per normal and was running fine. symptoms NOW do seem to be what can be described as the VCT not working BUT i believe i would havve seen these symtoms with the stock turbo if that was the case.

also the turbo i ordered was deffinetley a PU..

preload was set correctly by tuner.

I will post up dyno sheet comparing my car and another r33 with same turbo for those who are intrested.

Thanks scott, mods are:

FF plenuum (no leaks)

550cc injectors

bosch 040

FMIC (no leaks)

Aftermarket plumback BOV (no leaks

3" intake pipe (no leaks)

z32 AFM

electronic boost controller (have also tried boost tap)

Standard airbox but was also run without lid and filter to try issolate the problem

AFR is perfect

Have also checked piping and intercooler last night to see if something was left in there to block them but was all good.

[s13kris]

also 3"bellmouth front/dump

3"catco hiflow cat

and 3"or 3.5"for the rest of the exhaust

[Trozzle]

I had the same problem with my turbo when I first got it tuned, it was because it was damaged in postage (no doubt after customs/mail security ppl opened it as a random check) therefore the wastegate was jamming open slightly.

Disconnect actuator rod and open/close the wastegate by hand. Do this for a good 5 minutes to make sure it doesn't get stiff depending on how fast you open it or where you put pressure. Make sure it moves smoothly and freely. It's possible damage from postage or installation like mine was.

[s13kris]

im the pink line and the other customer with the same turbo is the blue line

[Trozzle]

Yep, looks to be the exact same thing I had. Check that the wastegate is actually closed. Have a look at the arm, it should be at right-angles to the dump pipe. If not, then give it a gentle tap with something to try to close it further. If it doesn't wanna close properly, remove dump pipe and feel the flapper to make sure it's sealed. If so, remove actuator rod and play around with it like I said before.

It really looks like the wastegate isn't closed correctly, exactly how mine looked. Made correct peak power for the boost level, just too FOREVER to get there.

[s13kris]

flapper is closed up. next on the list is testing the VCT. spoke to Tao today(hypergear) and he strongly believes thats the problem so its deffinetley worth a try since theres nothing else left to check

[s13kris]

some pics for those having similar problem and dont know what to look at

[hypergear]

Graph appeared to be an massive air leak, but there is nothing wrong with the wastegate assembly and turbo's obviously working. I really delt any air leaks to came from the turbo assembly. Check VCT, cam timing, and any cold side leaks.

[s13kris]

Thanks Tao will be checking VCT tommorow and ill get a mechanic to check out the cam timing. theres deffinetly no leaks on the cold side though. im starting to get suspicious about the vct as it seems my problem is within its power range if that makes any diffrence. i will keep you posted.

[s13kris]

I also doubt that its the turbo atm. really excited about getting it sorted though im looking forward to seeing what this turbo is capable of. how well would it perform on an RB25/30? have you had any customers use it for that purpose or is it to small? i think it will be great response for a street car. but will miss out on abit at top end.

[hypergear]

This turbo will be maxing out around the 290rwkws mark, Rb30 will also be making similar amount with lot better response and lot more torque. Its not really a small turbos its more like a baby 3540 which is the biggest I can squeeze into a OP6 rear housing.

[GTScotT]

Im confident in saying the RB30 would actually cap off much earlier in power to the RB25. The rear housing would bring the chra up to vmax much earlier and therefore would be pumping hot air into a housing not big enough to support it.

Kind of like neeing a 50mm gate to run a .63 gt30, its because the .63 rear will make shaft speed reach the turbos max flow too early and you will need to bleed off excess via the massive gate.

In regards to your issue Kris, I would be trying to tie the gate shut and run it without the vac line connected. Remove and block the line that goes to the actuator, then use some steel wire or similar to tie the gate shut also. Be careful not to boost to infinity and beyond because im confident your motor wont like it.

Do the simple test on your VCT also, its a good avenue to check. With the comment noting that you didnt have the problem prior to installing the turbo, I am assuming you also didnt have whatever is tuning it prior to your turbo install either. You have not noted what ecu you are running? At the moment it is fair to assume you may not even have VCT connected, please elaborate on this particular item first.