R34Gtr Tune: Opinions Wanted Please.

[johno34]

Hi,

I have been reading this forum for quite some time, but i needed to ask a specific question in relation to my particular car.

I have an R34GTR, it has an aftermarket front pipe and exhaust. Hi-Flow cat, yellow jacket coil packs, pod filters, Apexi Power FC ecu, electronic boost controller, Hi- flow fuel pump with a nismo fuel reg and these turbos http://www.ebay.com....=item1c1cadc7d4

It also still has standard injectors and air flow meters.

My question is this, in the cars latest tune, it has only achieved 260kw atw at 19p.s.i boost.

This seems to be low to me considering that the turbos are supposedly rated to flow a lot more power than that.

There is plenty of fuel and the injectors haven't been maxed out.

I haven't got adjustable cam gears on it, i'm wondering if that would help?

But i thought that they would mainly improve mid range.

I have to say though that the car does have fantastic mid range power, but according to the dyno sheet, seems to run out of puff higher up.

(As can be seen on the attached dyno sheet. Its the darker line 260kw atw run. Sorry about the quality)

The exhaust didn't sound restrictive on the dyno, and the car wasnt missing at all and seemed to rev quickly and smoothly.

The engine is also in excellent mechanical condition.

In its previous tune the car achieved around 250kw atw on 1 bar boost with its standard turbos, it wasn't pushed any higher due to ceramic wheels.

What do you guys think?

Any constructive critism would be appreciated.Thanks.

[Truffles]

What turbos did you have on it? You've specified they're no longer standard but not what they are.

[R31Nismoid]

As per the link - he put R33 N1 turbos onto it.

So a MASSIVE step back in response performance (as evident by boost response), for not a lot more power in top end... Hence why many people view R33/R32 N1 turbos are a downgrade.

Yes they should be making more power, talk to the tuner and fine out what the issue is. Could be 100s of things from cam timing to an exhaust restriction.

[johno34]

The turbos that were on it to begin with were the standard R34GTR turbos with ceramic wheels.

The turbos i have on now apparently are a hybrid combination and have a 60.1mm O.D compressor and the exhaust turbine is 53.0 mm O.D.

Click on the ebay link to see the turbos that are on it now.

The turbos do take a little bit longer to come on, but they do have a stronger mid range with over 20kw atw more power.

But you are right that in the top end they taper out.

I just thought that they would've kept pulling at about the same rate as the factory ones, and kept that advantage right through to the redline.

Edited February 6, 2013 by johno34

[R31Nismoid]

Ye I clicked the link, they are just 1980s N1 turbo cores mate, all the lag of -5s with the peak power of -7s... So the worst part of either turbo really (lag and no proper top end).

You could have had that 20kw more, 500rpm earlier if you got new generation Garretts.. So ye...

Anyway you've got what you've got, and you'll have to deal with it. Either way you still need to get the setup fixed as it should be 30rwkw more peak on around 20-22psi

[johno34]

Yeh i know............coulda, shoulda, woulda.

I was trying to improve it on a budget........the car does feel better to drive, and it does feel noticeably stronger mid range.

These factors , plus i got rid of the worrying ceramic wheels, makes it good bang for your buck in my opinion.

They were $1,000.00 cheaper than -7's.

Like you said, they should have have more in them.

Would adjustable cam wheels be a move in the right direction?

My exhaust also has an offset front muffler which may be restricting it as well.

So i might see about taking it out.

Thanks for the input.

My tuner did try increasing the boost, but the power gain in the cars current state wasnt advantageous in his opinion.

i.e not worth the gain from the boost increase, i think he said 4kw for 1p.s.i of boost.

Edited February 6, 2013 by johno34

[R31Nismoid]

Cam gears won't fix the power issue... Your cam timing might be out though... Always fix the setup and get it running right before changing parts and fine tuning it is always a good way to work.

Offset might be a problem, might not. Just drop it and do a dyno run or two. If suddenly more timing/boost goes into it then you have your culprit. It might even increase in power naturally so ensure the tuner is watching carefully.

[johno34]

So in your opinion, i should check the cam timing?

Besides that and the exhaust, i really can't think of anything else which could attribute to it being a significant amount of power down.

Thanks again.

[R31Nismoid]

Could be the tune itself, cam timing yes for sure check and the exhaust for restrictions.

Could be leaky cooler piping or even a case of a rag being left in the cooler piping and semi blocking it somewhere (seen that before). Lots of things to look at really.

[w34ponGT]

i was going to buy those turbos but got highly warned not to touch them. just go big single to4z

[johno34]

i was going to buy those turbos but got highly warned not to touch them. just go big single to4z

Single turbo set up would be nice, but a HUGE difference in price to do it properly!

I got a quote to change the internals and replace the ceramic wheels on my original standard R34GTR turbos and the price was higher than the turbos i bought.

So in that respect, more performance with steel wheels is a bonus.........i think.

[gtr jet]

I'm not saying that you got ripped off but I paid less than that for my R34 N1's. Pays to shop around sometimes.

[johno34]

I'm not saying that you got ripped off but I paid less than that for my R34 N1's. Pays to shop around sometimes.

I did look around for prices everywhere i could find, obviously i didn't look hard enough.

Where did you get your R34 N1's from for that price, thats very cheap from what i got quoted.

Were they new, re-conditioned or used?

Or........did they fall off the back of a truck?

Edited February 6, 2013 by johno34

[gtr jet]

I bought them second hand and then just checked that they were in good condition. I remember I got quoted roughly $1000 each to have my stockers high flowed and steel wheeled. Then I found the N1's for $1100.

Just luck I guess. But I have seen them come up for around the $1500 mark.

[johno34]

I bought them second hand and then just checked that they were in good condition. I remember I got quoted roughly $1000 each to have my stockers high flowed and steel wheeled. Then I found the N1's for $1100.

Just luck I guess. But I have seen them come up for around the $1500 mark.

Good that you got a good deal.

I didn't really want to buy second hand turbos if i could help it, if anyone was going to buy a dud set, it would be me!

Yes, they are expensive to do up with steel wheels and hi-flow, i got quoted $850.00 each to do just that.

What mods and power do you have with your GTR?

[gtr jet]

Just all the basic stuff. Turbo's, exhaust, fuel pump, injectors and tuned on E85 to 325kw.

[w34ponGT]

e85 turns me on

[johno34]

e85 turns me on

O.K then.