Jump to content
SAU Community

Hi-flowing vs new turbos?

maccattack
 Share

Recommended Posts

Abo Bob Grand Master

Abo Bob

Posted
Posted

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.

:thumbsup:

  • Replies 53
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Merli Grand Master

Merli

Posted
Posted
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.

 

:thumbsup:

Well................... not really :D :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 Grand Master

Merli

Posted
Posted

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

PANGES Apprentice

PANGES

Posted
Posted
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.

 

:cheers:

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 Grand Master

Sydneykid

Posted
Posted
Well................... not really :):rofl:

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 :cheers:

  • 1 month later...
R33vit Experienced

R33vit

Posted
Posted
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 :P

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

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Predator1
      Tomei gasket

      By Predator1 · Posted

      Didnt realise RB's had more then 1 head.
    • MBS206
      Unpeeling the Orange

      By MBS206 · Posted

      I'm normally copping my own abuse from neglecting my daily drivers. "Those suspension bushes will last a bit more", "Don't worry about the oil leak, just keep topping it up". The project cars I'm always doing things slowly on them as I'm wanting them to be done better, and neater, and nicer. Luckily I don't have to deal with 18 year old Matt's "Learning to wire" stuff in the project cars. And there's only one piece of wiring I'm displeased about in the Landcruiser, and it's about to be cut out... However, the box loads of parts that have been going through this place lately for the Landcruiser... Brake pads Brake Rotors Full handbrake overhaul Wheel Bearings Seals Swivel hubs Steering Boxes Half the suspension joints Shocks Air bags (Ones to go in the rear springs for towing) Water pump Timing kit Lower timing case Harmonic Balancer Radiator Lots of other little seals and shits Gas struts for the bonnet New power window switches And god knows what else I've forgotten... Ha ha ha I have my fingers crossed the pinion seals don't start leaking on the diffs, that the transfer case doesn't leak, and the gearbox input shaft doesn't leak, nor the rear main seal. As they're about the only seals I haven't replaced in the driveline! I'm seriously eyeing off buying new caliper rebuild kits front and rear brake calipers... I'll probably recheck all the valve clearances soon too, and hopefully, it should be all good and sweet to haul some long distance trips again!
    • GTSBoy
      Unpeeling the Orange

      By GTSBoy · Posted

      Every time I pull my 3x gauges out of the console and see the crack-addict way that I did the wiring, and I just can't bring myself to tear it all apart and "make it nice", because it is currently working. In fact, the last time I was in there I probably made it worse.
    • Kinkstaah
      Unpeeling the Orange

      By Kinkstaah · Posted

      The best part is when you own the car long enough that you look back and find your OWN ham fisted amateur shit!
    • MBS206
      Unpeeling the Orange

      By MBS206 · Posted

      The annoying part about neglect, is when you start to replace one thing, and find ten more broken things. Ham fisted monkey repairs you normally only find out about when trying to do something unrelated! Ha ha   Neglect you can kind of anticipate the huge costs to fix it all. Ham fistedness is normally a shock the first time your work on a new old car, as everything "looked" good before.
×
×
  • Create New...