Jump to content
SAU Community

Recommended Posts

ok,

I'm running a pair of Garrett GT 2860 - 7's in my GTR, and i'm getting full boost are 6k, which is way too high in the rev range.

I currently had a Gizzmo MSIbc installed, and I have tried a manual controller and its still lagging.

I fitted the factory boost control solenoid and it ran 8 psi @ 4k which is about right.

Anyone else had a problem with excess lag in a GTR? Or have any idea why its lagging so much?

Mate suggested that the wastegates are opening too early, if this is the case can I restrict them somehow?

Any suggestions welcome

-Michael-

Link to comment
https://www.sau.com.au/forums/topic/355457-car-way-too-laggy/
Share on other sites

I'm running a pair of Garrett GT 2860 - 7's in my GTR, and i'm getting full boost are 6k, which is way too high in the rev range.

I currently had a Gizzmo MSIbc installed, and I have tried a manual controller and its still lagging.

I fitted the factory boost control solenoid and it ran 8 psi @ 4k which is about right.

With proper boost control you should be at 16psi by 4k, not 8.

How did you setup the wastegate actuators?

A friend of mine is having the same problem with his GTR, twin GT-RS turbos, 272 cams, etc... Full boost by 5500rpm. I'll find out whats going on when he gets his car back from the tuner.

GT-RS are far bigger and laggier than -7s. Did you mean GT-SS?

A friend of mine is having the same problem with his GTR, twin GT-RS turbos, 272 cams, etc... Full boost by 5500rpm. I'll find out whats going on when he gets his car back from the tuner.

Sounds spot on for those turbos and cams on a 2.6 or 2.8

he said thats whats under the hood, i havnt seen them myself. the car makes 460 awkw though. Would gt-ss make that power??

No way in hell mate, you have GT-RS x 2 there my friend.

GT-SS are hard out pushing 330KW let alone another 130KW on top of that, definitely GT-RS

The actuator rods have a thread on them so you can tighten / loosen them. This would be the first place to look.

Try tightening them up by screwing the end on so the total rod length is shorter. This means the actuator needs to see more boost before it starts opening the wastegate up further.

A friend of mine is having the same problem with his GTR, twin GT-RS turbos, 272 cams, etc... Full boost by 5500rpm. I'll find out whats going on when he gets his car back from the tuner.

Well GT-RS turbos - what do you expect? 800hp of turbo isn't going to be responsive on a 2.6ltr

Sounds perfectly normal - and totally unrelated to the OP as he is talking about R34 N1 turbos.

I'm running a pair of Garrett GT 2860 - 7's in my GTR, and i'm getting full boost are 6k, which is way too high in the rev range.

I currently had a Gizzmo MSIbc installed, and I have tried a manual controller and its still lagging.

I fitted the factory boost control solenoid and it ran 8 psi @ 4k which is about right.

Anyone else had a problem with excess lag in a GTR? Or have any idea why its lagging so much?

Well you've answered your own question.

The EBC install is incorrect. If you've put the factory setup on there and it was instantly more responsive... Then it's rather obvious where the issue is...

Well GT-RS turbos - what do you expect? 800hp of turbo isn't going to be responsive on a 2.6ltr

Sounds perfectly normal - and totally unrelated to the OP as he is talking about R34 N1 turbos.

Well you've answered your own question.

The EBC install is incorrect. If you've put the factory setup on there and it was instantly more responsive... Then it's rather obvious where the issue is...

Well if the EBC is the issue, it would have to be simply doing nothing. By that I mean having the same effect as no boost controller at all....would that really amount to that the increase in lag? Sure, it's been proven to be the issue by his simple troubleshooting - yet I can't see how a boost controller will be the difference in 2000rpm

The actuator rods have a thread on them so you can tighten / loosen them. This would be the first place to look.

Try tightening them up by screwing the end on so the total rod length is shorter. This means the actuator needs to see more boost before it starts opening the wastegate up further.

+1. After you tighten the actuators, make sure they are both working in unison by applying boost to the signal line, and making sure they move together. Otherwise you could flog out a turbo.

For clarity, it appears you have two boost control problems.

1. Probably actuatory adjustment

2. Boost controller installed incorrectly/broken.

+1. After you tighten the actuators, make sure they are both working in unison by applying boost to the signal line, and making sure they move together. Otherwise you could flog out a turbo.

True this - very important the actuators are configured consistently across both turbos.

OK, i'll take a look at the actuators on the weekend, hope they can be adjusted without removing too much

I'm pretty sure the install is correct, there are 2 lines, one for actuators another from manifold. Boosts to target, just takes too long, old controller did the same thing, that's why I replaced it, thought the unit was faulty.

On the note of take it to a pro, can you recommend someone?

Thanks for the input :)

By target, do you mean higher than your actuator's spring rating? Try running a vac line directly from the boost source off the intercooler piping or wherever you're getting it from to the actuators. Completely remove the boost controller from the equation. You said with the standard boost solenoid in place, it made 8psi? If that's the rating of your actuators, I dare say that's probably the issue. While your turbos aren't HUGE, they're certainly flowing a decent amount of air and therefore exhaust even at that low boost, so I wouldn't be surprised if it was just simply overcoming the wastegate flap and pushing it open.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Yup. You can get creative and make a sort of "bracket" with cable ties. Put 2 around the sender with a third passing underneath them strapped down against the sender. Then that third one is able to be passed through some hole at right angles to the orientation of the sender. Or some variation on the theme. Yes.... ummm, with caveats? I mean, the sender is BSP and you would likely have AN stuff on the hose, so yes, there would be the adapter you mention. But the block end will either be 1/8 NPT if that thread is still OK in there, or you can drill and tap it out to 1/4 BSP or NPT and use appropriate adapter there. As it stands, your mention of 1/8 BSPT male seems... wrong for the 1/8 NPT female it has to go into. The hose will be better, because even with the bush, the mass of the sender will be "hanging" off a hard threaded connection and will add some stress/strain to that. It might fail in the future. The hose eliminates almost all such risk - but adds in several more threaded connections to leak from! It really should be tapered, but it looks very long in that photo with no taper visible. If you have it in hand you should be able to see if it tapered or not. There technically is no possibility of a mechanical seal with a parallel male in a parallel female, so it is hard to believe that it is parallel male, but weirder things have happened. Maybe it's meant to seat on some surface when screwed in on the original installation? Anyway, at that thread size, parallel in parallel, with tape and goop, will seal just fine.
    • How do you propose I cable tie this: To something securely? Is it really just a case of finding a couple of holes and ziptying it there so it never goes flying or starts dangling around, more or less? Then run a 1/8 BSP Female to [hose adapter of choice?/AN?] and then the opposing fitting at the bush-into-oil-block end? being the hose-into-realistically likely a 1/8 BSPT male) Is this going to provide any real benefit over using a stainless/steel 1/4 to 1/8 BSPT reducing bush? I am making the assumption the OEM sender is BSPT not BSPP/BSP
    • I fashioned a ramp out of a couple of pieces of 140x35 lumber, to get the bumper up slightly, and then one of these is what I use
    • I wouldn't worry about dissimilar metal corrosion, should you just buy/make a steel replacement. There will be thread tape and sealant compound between the metals. The few little spots where they touch each other will be deep inside the joint, unable to get wet. And the alloy block is much much larger than a small steel fitting, so there is plenty of "sacrificial" capacity there. Any bush you put in there will be dissimilar anyway. Either steel or brass. Maybe stainless. All of them are different to the other parts in the chain. But what I said above still applies.
    • You are all good then, I didn't realise the port was in a part you can (have!) remove. Just pull the broken part out, clean it and the threads should be fine. Yes, the whole point about remote mounting is it takes almost all of the vibration out via the flexible hose. You just need a convenient chassis point and a cable tie or 3.
×
×
  • Create New...