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Car Way Too Laggy

GimpyDammit

By GimpyDammit,
in Engines & Forced Induction

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GimpyDammit Community Regular

GimpyDammit

Posted
Posted

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-

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MrStabby Grand Master

MrStabby

Posted
Posted

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?

MrStabby Grand Master

MrStabby

Posted
Posted

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?

N1GTR Grand Master

N1GTR

Posted
Posted

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

Nee-san Grand Master

Nee-san

Posted
Posted

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

paulR32gtr Mentor

paulR32gtr

Posted
Posted

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.

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

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...

Trozzle Grand Master

Trozzle

Posted
Posted

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

MrStabby Grand Master

MrStabby

Posted
Posted

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.

paulR32gtr Mentor

paulR32gtr

Posted
Posted

+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.

GimpyDammit Community Regular

GimpyDammit

Posted
  • Author
Posted

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 :)

Trozzle Grand Master

Trozzle

Posted
Posted

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.

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