2860-5 Too Much Lag

[trvgtr]

Hi all, wondering if someone can help me out. I recently installed 2860-5 on my R34 GTR along with hks dumps, power fc, sard 800cc injectors and 044 pump. Got the car tuned at croydon racing, the car made 304.4kws at all 4 but i dont see boost until 6500rpm!!! This seems way too high and think there maybe a problem somewhere. Things i have checked so far:

- disconnected wastegates and drove incase gates slightly open (gates ok)

-checked for boost leaks (none evident)

-drove with no cat incase blocked (not blocked)

I have spoken to a few people and they say that they are seeing full boost by 4000-4500rpm.

The engine is stock (no cam gears or cams) but was told they shouldnt make too much of a difference especially not 2000rpm!!!

Any help much appreciated

[TiTAN]

whats controlling the boost? spring pressure in the wastegates? EBC? bleed valve?

[Parag0n]

I think the most important part we are missing is what did the tuner have to say?

[The Dan]

Disconnecting the gates is not going to do SFA.

What did you hope to achieve by doing this and what happened when you did?

You need to adjust them with correct pretension.

[PM-R33]

Got a dyno graph with a boost curve? Should be easy to tell if something is wrong.

[R31Nismoid]

Disconnecting the gates is not going to do SFA.

What did you hope to achieve by doing this and what happened when you did?

You need to adjust them with correct pretension.

lol ye exactly. All it will do is let them blow open soon as they see pressure... pointless excercise that was.

If anything you should be wiring the gates SHUT to see if the actuator setup is your issue.

Did you use NEW/HD actuators? Or the ones off your factory turbos? Cause the factory turbo's ones... no good.

That sounds like the issue, i bet you wire them shut, boost comes on hard and around the 4000rpm give/take which is clearly actuator setup related.

[trvgtr]

Oh ok did not realise that they needed to be wired shut, will give it a try. They are the the standard wastegates that came new with the turbo's (purchased from gcg) so not sure what the springs are preset at, does anyone know?. This definitly sounds like it is the problem though, thanks heaps for all your help, will keep you posted.

cheers...

[gtr fan]

I just bought the same turbo for a r32. Look forward to hearing your results. But like someone else said 'What did the tuner say'?

Also what boost pressure were you running?

Also you wanting to sell your stock R34 GTR Dumps?

Edited December 18, 2009 by gtr fan

[Beer Baron]

what are you using for boost control, and what boost level are you running as max boost?

[trvgtr]

When i took the car to croydon i told them i wanted 300awkws which it achieved, i did not see boost vs rpm dyno sheet only power. I called them and explained to them that it was far too laggy, they told me to check a few things and if they dont work bring it back to them as the wastegates may be set wrong. The car is tuned at just over 1.2 bar using turbosmart t-piece (bad choice i know) but before i had the car tuned with just bolting the turbos to the stock motor and no t-piece, it still wouldnt hit full boost till 6500rpm.

I have just tried to tighten the wastegate rods but the rods have a crimp to stop you adjusting them, any ideas?

Also called gcg, they told me they have never heard of this before and i should be seeing full boost at roughly 4000rpm. They told me they are 1.0 bar actuators standard on the 2860-5's.

Edited December 18, 2009 by trvgtr

[MrStabby]

Oh ok did not realise that they needed to be wired shut, will give it a try.

Just remember to back off when you've hit a bar or so, you dont want to risk blowing the motor. Also depending on how the tune is, bringing the boost on earlier may get you into dangerous territory. It would be worth checking on the dyno.

Might be easier to just disconnect the signal to the actuators first. If that fixes it then your boost control is stuffed.

You know you'd have much less lag with -9s right?

[R31Nismoid]

300 at the tyres and you decided on -5's? ugh... -9's are the turbo for 300-330rwkw!!! People still seem to fail to understand or research correctly.

-5s are 400rwkw turbos. Not 300.

With 9's I have boost building around 2800rpm, by 3300-3500rpm im hitting 1bar. Happens to fast for me to take notice anything after that being RWD, gotta pay attention.

If you are only making 300 on what, 16psi... thats a bit harsh. I'm sitting around 280 on 16 with smaller turbos, and better response (when compared to working -5s).

And ive only got a half baked tune in there at the moment because i haven't put injectors/afm's etc onto it yet...

[mazman]

Just so people know, as Trav did not word it properly... He disconnected the pressure lines TO the wastegate's, he didn't actually disconnect the wastegate's, so he was eliminating the possibility of a fault with t-piece/turbosmart boost valve.

Therefor the wastegates were closed the whole time as they did not see any pressure, it was still laggy.

His wastegate rods cannot be adjusted/pre-tensioned, they seem to be preset and locked in via crimping.

1.2bar = ~17.4psi

I would of thought having it dyno'd at croydon, if there was something obviously wrong such as being way to laggy, they would of mentioned something or called him up saying... listen, we noticed a big issue with turbo lag and we need to check it further etc etc...

Can someone tell me what the rb26 likes in the way of timing? @4K and >above ( @17psi)

[MrStabby]

Just so people know, as Trav did not word it properly... He disconnected the pressure lines TO the wastegate's,

You havent got it quite right either - the lines are connected to the actuators not the wastegates :-)

I would of thought having it dyno'd at croydon, if there was something obviously wrong such as being way to laggy, they would of mentioned something or called him up saying... listen, we noticed a big issue with turbo lag and we need to check it further etc etc...

Fair call.

[R31Nismoid]

Just so people know, as Trav did not word it properly... He disconnected the pressure lines TO the wastegate's, he didn't actually disconnect the wastegate's, so he was eliminating the possibility of a fault with t-piece/turbosmart boost valve.

Therefor the wastegates were closed the whole time as they did not see any pressure, it was still laggy.

How do you work that out?

Removing the line simply lets them run off the actuators, if still connected.

That will not hold them shut.

Therefore it is not as you said, closed the whole time, it is still riding on the actuators being setup correctly to stay closed.

Something that is yet to be confirmed and the most likely cause at this stage.

[R31Nismoid]

I would of thought having it dyno'd at croydon, if there was something obviously wrong such as being way to laggy, they would of mentioned something or called him up saying... listen, we noticed a big issue with turbo lag and we need to check it further etc etc...

Totally depends.

If you are given a car and told specifically to tune it, you do that. It sounds like they didn't do any of the work on the car either.

I've seen many a workshop go above and beyond only to be hammered later by silly owners complaints.

Not saying this is the case here at all, just another perspective to look at because we clearly do not have all the facts thus far. Lots of pieces missing.

[mazman]

How do you work that out?

Removing the line simply lets them run off the actuators, if still connected.

That will not hold them shut.

Therefore it is not as you said, closed the whole time, it is still riding on the actuators being setup correctly to stay closed.

Something that is yet to be confirmed and the most likely cause at this stage.

Yes, leaving them run off the actuators, wich GCG told him are set at 1bar and prest already to correct tension.

I dont know what the pretension is or how much it should be, but you cant adjust it the way they left it/locked it, so its set to the way they want it ( but like you say, doesnt mean the pretension is set right from factory ).

We tested the actuators and they start to open at 15psi, so they are closed at least till 15psi or so with line pressure to them.

And there is a fair bit of tension on the wastegate flap keeping it closed by the rod/actuator, but is it enough tension? i dont know.

How much tension should there be, is there a set rule/testing procedure for that?

Edited December 18, 2009 by mazman

[bigmikespec]

300 at the tyres and you decided on -5's? ugh... -9's are the turbo for 300-330rwkw!!! People still seem to fail to understand or research correctly.

-5s are 400rwkw turbos. Not 300.

With 9's I have boost building around 2800rpm, by 3300-3500rpm im hitting 1bar. Happens to fast for me to take notice anything after that being RWD, gotta pay attention.

If you are only making 300 on what, 16psi... thats a bit harsh. I'm sitting around 280 on 16 with smaller turbos, and better response (when compared to working -5s).

And ive only got a half baked tune in there at the moment because i haven't put injectors/afm's etc onto it yet...

You are starting to sway me Nismoid with your -9's theory. Lean on them enough, E85 (or race fuel on the track) with built engine and appropriate headwork... 350kW, maybe? Full boost 3.5k and rev to 8k only for reliability, less stress on every other part of the drivetrain...

Anyway, don't stress and do something silly, take it to your tuner and tell him what is on your mind. Ask dumb questions otherwise you won't learn.

[R31Nismoid]

You can get 330rwkw on PULP, its the same as GT-SS which is what i have now

I only rev to 8k as well. Its certainly still pulling nice and hard. Obviously it's not the pin you to the seat feel of turbos of much larger size, but its not 'dying' out either way.

I wish i had my setup done so i could post up some results... will be Feb/Mar before i get it back, few delays with overnight parts from Japan.

If you cant make 360 on E85 i'd be nothing short of surprised in all honesty. On a good motor, they would be sweet.

Im doing it all with just factory cams, and a minor head tidy up as well, nothing big and costly in the head.

Depends how much power you need for the circuit though. A built motor, nice safe tune and 350-360rwkw with response to boot would be very nice.

But then -5's smashing 400rwkw on PULP is also very nice

[trvgtr]

Totally depends.

If you are given a car and told specifically to tune it, you do that. It sounds like they didn't do any of the work on the car either.

I've seen many a workshop go above and beyond only to be hammered later by silly owners complaints.

Not saying this is the case here at all, just another perspective to look at because we clearly do not have all the facts thus far. Lots of pieces missing.

Yes i agree with you, Iam not blaming croydon at all, i done all the work myself and took it to them just for a tune thats it. Iam taking it back there tomorrow to see if they can sort it out, will keep you posted, cheers...