Hi-flowing vs new turbos?

[Abo Bob]

Going by your details as posted above Merli, unless you're talking about drag racing that drop between 1st and 2nd is pretty much irrelevant.

If talking track, 2750 between 2nd and 3rd is a much smaller powerband and even that would only be used at a tight track like Wakefield.

A consideration maybe?

I wish I knew what my ratios were.

[Merli]

Going by your details as posted above Merli, unless you're talking about drag racing that drop between 1st and 2nd is pretty much irrelevant.

 

If talking track, 2750 between 2nd and 3rd is a much smaller powerband and even that would only be used at a tight track like Wakefield.

 

A consideration maybe?

 

I wish I knew what my ratios were.

 

Well................... not really :D

Are you saying that you only use 5750-8500 rpm whilst driving on the track? Often it's not feasible to change down a gear to keep it in that rev range...

Example:

A tight corner that should be taken in 3rd gear at about 5000 rpm can't be taken in 2nd gear, as that would equate to 7500rpm in 2nd gear (with R33 GTR gearing). You'd actually lose time in the extra two gear changes needed to use 2nd gear into and out of that corner, and you'd only be in 2nd gear for about 0.5 seconds as it revs from 7500-8500rpm anyway.... Make sense?

In reality, you'd be aiming to have a strong 4500-8500rpm range around the track...

[Merli]

Oh, and your gear ratios are the same as an R33 GTS-t:

1st 3.214

2nd 1.925

3rd 1.302

4th 1.000

5th 0.752

Final 4.111

[Abo Bob]

That's a good point although I guess it applies to SK's theory as well.

Mine is tiptronic so different diff ratio and gear ratios. Only 4 gears but seem to work good .

[Merli]

Oops, sorry mate...

Here are the gear ratios for the R33 GTS-t Auto box... The R34 Tiptronic is just an automatic gearbox, so I assume it would be the same ratios as the R33 Auto?

1st - 2.785

2nd - 1.545

3rd - 1.000

4th - 0.694

Final Drive - Dunno, probably 4.111

[Abo Bob]

Ahh, that explains why I hate 4th gear. Good thing I don't really need it.

[PANGES]

Going by your details as posted above Merli, unless you're talking about drag racing that drop between 1st and 2nd is pretty much irrelevant.

 

If talking track, 2750 between 2nd and 3rd is a much smaller powerband and even that would only be used at a tight track like Wakefield.

 

A consideration maybe?

 

I wish I knew what my ratios were.

 

lol, I have an R34 RB25DET that I'm swapping into my 89 240sx SOOO i found the gear ratios for the GT-T and got the answers..... assuming your car is manual transmission

Engine speeds in top gear:-

30 MPH = 977 RPM 40 MPH = 1303 RPM 50 MPH = 1629 RPM 60 MPH = 1955 RPM

70 MPH = 2280 RPM 80 MPH = 2606 RPM 90 MPH = 2932 RPM 100 MPH = 3258 RPM

Top Speed in 1 gear = 37.574 MPH

And changes into 2 gear at 4000 RPM dropping 2800 RPM

Top Speed in 2 gear = 63.876 MPH

And changes into 3 gear at 4338 RPM dropping 2462 RPM

Top Speed in 3 gear = 100.120 MPH

And changes into 4 gear at 5015 RPM dropping 1785 RPM

Top Speed in 4 gear = 135.763 MPH

And changes into 5 gear at 5181 RPM dropping 1619 RPM

Top Speed in 5 gear = 178.176 MPH

And changes into 6 gear at 5804 RPM dropping 996 RPM

Top Speed in 6 gear = 208.746 MPH

oh yeah, ignore the 6th gear (obviously)

[Sydneykid]

Well................... not really

Are you saying that you only use 5750-8500 rpm whilst driving on the track? Often it's not feasible to change down a gear to keep it in that rev range...  

Example:

A tight corner that should be taken in 3rd gear at about 5000 rpm can't be taken in 2nd gear, as that would equate to 7500rpm in 2nd gear (with R33 GTR gearing). You'd actually lose time in the extra two gear changes needed to use 2nd gear into and out of that corner, and you'd only be in 2nd gear for about 0.5 seconds as it revs from 7500-8500rpm anyway.... Make sense?

In reality, you'd be aiming to have a strong 4500-8500rpm range around the track...

Shoot Merli, you really have got it

[discopotato03]

Back to the turbos , Garrett do a GTR replacment BB turbo that's nearly identical to the HKS GT2530 . Could save you some money if buying new . Are the R34 GTR's turbo's Garrett BB's ? Same ?

Cheers A .

[discopotato03]

SK , have you tried the GT30R as a single on an RB26/30DET . Could this combination be the perfect torque spread animal in the same vein as GT2530's on an RB26 ?

Thanks A .

[R33vit]

Try this quick XLS calc for the above formule

Oh yeah, enter your details in the yellow sedtions

[R33vit]

Oh yeah. Enter you details in the yellow sections

[R33vit]

That seems simple enough... Cheers!

But after a bit of simple maths, I've worked out the revs drop for each gearchange for an R33 GTR

Gear Change Rev Drops (rounded for simplicity)

1st-2nd    3410rpm (8500rpm -> 5090rpm)

2nd-3rd    2750rpm (8500rpm -> 5750rpm)

3rd-4th    1970rpm (8500rpm -> 6530rpm)

4th-5th    2110rpm (8500rpm -> 6390rpm)

So R33 GTR owners should be aiming for a powerband between 4500rpm -> redline (taking into account poor drivers holding you up)... Is that right?

Makes sense... I can understand why people consider GT2530s perfect track turbos for the GTR, since that pretty much fits the required powerband prefectly!

Very interesting, thanks!

Andrew

Try this

[BBQ]

Andrew

 

Try this

Sweet that gear ratio calc is the way to go.. Saves me using my brain.

Good Stuff R33vit.