Acceptable Powerband.

[Nee-san]

Hey guys,

I'm interested to see what people consider to be a reasonable power band; IE full boost ---> Redline, for a street car.

at the moment i make fullboost at 5.2k or a touch later and pull all the way to redline (8k), this is in a built 32 GT-R with 33 N1 turbos.

Although I already knew this was rather laggy, It was driven home to me when i was given the opportunity to drive a mates 32 with GT-SS's, the response was phenomenal.

As many of you may have seen, I have been deciding which way to go with turbo's at the moment, wanting to keep the twins configuration and the standard manifold as mine has been cleaned up i have a few options available to me.

I have decided I would not want to go smaller then the output of a pair of -5's, but it seems my knowledge of what's available is lacking, as I detect a bit of a gap in the range between -5's and -10's or GT-RS's.

Sorry for the long and convoluted wind up but my main points are this:

What is an acceptable power band for a street driven track car ?

Is there a turbo that is above the -5 and below the GT-RS/-10 ?

Would -10's/GT-RS's be too laggy or surge in my application ?

I've gotten in trouble for not posting enough detail before so the car is:

2.7L or nigh on, not a stroker.

33 N1 turbos

Built engine

light headwork

portmatched inlet manifold

trust 4" intercooler

264" Inlet and 272" Exhaust camshafts both with 10mm lift (HKS)

4" Exhaust.

Cheers,

Mitch.

Edited April 20, 2010 by Nee-san

[R31Nismoid]

GT-RS is 450rwkw+

So much more than R33 N1's will ever make. -5's will do 380-400rwkw on a good motor, GT-SS's around 330.

There are no turbos "in the middle" of any of those far as i am aware.

[Nee-san]

GT-RS is 450rwkw+

So much more than R33 N1's will ever make. -5's will do 380-400rwkw on a good motor, GT-SS's around 330.

There are no turbos "in the middle" of any of those far as i am aware.

Yeah, i thought it a little strange that nothing sort of falls into that gap...

anyway, what do you think about useable powerband ? the power of the GT-RS's is rather appealing but if im only reving it to around 8500 RPM will i have enough room to use it ?

The -5's really do look quite good its just that in the dyno thread ive seen a fair few setups fall short of the 420+KW im looking for.

If it helps, the car will be spending probably 80% of its track life at Queensland raceway.....

Thanks for the reply mate,

Mitch.

[Duncan]

One thing I can say.....R32 and R33 N1 turbos are about the worst thing on the market for response. Any modern, ball bearing turbo will make the same power 1500rpm sooner....or far more power at the same revs if you go larger

[Nee-san]

One thing I can say.....R32 and R33 N1 turbos are about the worst thing on the market for response. Any modern, ball bearing turbo will make the same power 1500rpm sooner....or far more power at the same revs if you go larger

Agreed, this is why im tossing up really, since as Ash has pointed out there is really no middle ground, GT-RS's or -5's for around queensland raceway it all comes down to which one....

I'm just not sure of the Pros or Cons each way as i havent personally worked with either of these turbos.

Cheers,

Mitch.

[joeyjoejoejuniorshabadoo]

a car that makes 380 on song by say 4000 revs should be faster around a track and more fun that a car that makes 420 by 5000 revs

personally i would be looking at possibly dropping your power level a tad and shooting for some response.

you could also go a twinscroll single setup...

[R31Nismoid]

There are a few that go around QR on here with power between 370rwkw & 440rwkw...

Hopefully one of them can pass a bit more experienced comment

Given you can get 400rwkw from -5's on a solid motor... it's only 20rwkw shy of what you "want" which is pretty close IMO

[dori34]

One thing I can say.....R32 and R33 N1 turbos are about the worst thing on the market for response. Any modern, ball bearing turbo will make the same power 1500rpm sooner....or far more power at the same revs if you go larger

Thank you for this post Duncan, i just saved myself from spending $1200 on R33 N1s

GT-SS would be the way to go if i was to upgrade when the stockers let go.

Also, how would you tell if the turbos came from a R32/R33/R34 ?

[R31Nismoid]

Part numbers on the turbos are different

[N1GTR]

What middle ground are you looking for?

As ash said, one option is about 330kw, the next finishes around 400kw, the next goes up around 450kw.

It's not like garrett will make bolt on turbos that suit 330kw, then a new set for 350kw, then a new set for 370kw, then a new set for 390kw, then a new set for 410kw etc

it may be worth going to QR when you know skylines will be there and just asking people in the pits

[STATUS]

go the -5's, compared to your N1's you will fill your pants on both sides.

[Harey]

HAHAHAHA thats funny as, but a bad image!

Who cares what is an acceptable powerband, you want the best power band you can get that will satisfy your max power level. -5s sound like they are the choice.

[GTRNUR]

I think -5's or -9's. Its torque and response out of the corners that make for a quick track car. Its the reason why the EVO's still kick many the GTR ass at track days. Lighter weight cars, plus also more respnse out of the corners.

If your racing a fast track though and are achiving 250Km/h+ on the straights then GTRS's and more power is worth considering so you can make up some time on the straights and sacrifice some out of the corner response (and stability).

Its been my limited experience that most of the time less powerful cars are easier to drive smoother around a track, and as a result produce lower lap times.

[NickR33]

T517z's are good for 360rwkw @ 20psi on my car... usable power from 4000 - 8500... there's your middle ground;)

dunno if you've got E85 up there but -5's with some E85 should get you over 400rwkw... heaps of power for track work IMO

[N1GTR]

T517z's are good for 360rwkw @ 20psi on my car... usable power from 4000 - 8500... there's your middle ground;)

dunno if you've got E85 up there but -5's with some E85 should get you over 400rwkw... heaps of power for track work IMO

Ive been in your car, before you owned it.

What a machine that thing is!

OP: As said, its up to you to find the amount of lag you're happy to put up with in the conditions you drive it in. Mine is between 3500/4000 and 8500rpm for HKS GTRS's although a 3L bottom end, that suits me, may not suit others. It would be a good idea to look through the dyno result threads in this section aswel, some decent info in there (aswel as a lot of crap results)

[paulr33]

i wonder what would happen if given a laggy powerband you change diff gears instead

does it make the car complete ass to drive or does it reasonablly shift it lower, ie more response

the evo specs reference 4.3 and 4.5 final drive vs GTR/GTST 4.11

[N1GTR]

i wonder what would happen if given a laggy powerband you change diff gears instead

does it make the car complete ass to drive or does it reasonablly shift it lower, ie more response

the evo specs reference 4.3 and 4.5 final drive vs GTR/GTST 4.11

There's someone on this board, who i doubt will see this thread, but has recently taken out a 6 speed box and put the stock 5 speed back in.

The car was pretty responsive (given its huge single turbo) and now is just all lag.

[paulr33]

in a 34R ? did they change diff gears as well or just the box?

BNR34r diff gears is 3.7 from memory

[N1GTR]

Sorry, BCNR33, just box

[NickR33]

Ive been in your car, before you owned it.

What a machine that thing is!

OP: As said, its up to you to find the amount of lag you're happy to put up with in the conditions you drive it in. Mine is between 3500/4000 and 8500rpm for HKS GTRS's although a 3L bottom end, that suits me, may not suit others. It would be a good idea to look through the dyno result threads in this section aswel, some decent info in there (aswel as a lot of crap results)

I can't imagine what another 100rwkw with the same (if not better) response would be like... but if I'm ever in NSW I'm coming round to find out! lol

I'm keen to try E85 next... figure as far as bang for buck at this point nothing can beat it

edit: yeah Paul the Mines 34GTR runs shorter diff ratios... I'm keen to try the GTS4 diffs, they are about 4.3 from memory... can't hurt the cruising speed that much, I hardly ever use 5th gear as with the big cams it runs more efficiently cruising at 3,500 - 4,000 rpm... you can hear its actually quieter at that rpm too which took some getting used to, looking down and seeing 4k on the tacho makes you want to shift up