[radium69]

Hello Guys,

Was wondering what topspeed you would be able to achieve with a R33 GTS-4.
Theoratical top speed that is.

I'm planning to do a big project with an RB30, but need to know the topspeed, and I have no idea what ratio's the diffs and gears are...

Hope to be hitting 8500RPM with stock RB30 and 25 head.

Thanks in advance,

 

[ATCO]

The diff gearing (3.4?) is the lowest (fastest acceleration) I believe. So don't expect that high, even at 8500RPM.

 

[radium69]

Thanks ATCO for your reply,

Are my calculations correct?

Final Drive GTS-4: 0,76
Tyres: 235/45/17
Diff: 4,36

Theoratical Topspeed @ 7000RPM = 256Km/h = 159Mph
Theoratical Topspeed @ 8000RPM = 291Km/h = 181Mph

8000RPM seems to be the best topspeed because of short diff and plenty of power (500Hp and 650NM)

 

[ATCO]

I'd go with those numbers. Just bear in mind that's real revs, not what tacho tells you as its notoriously inaccurate. 8000 on dash tacho is barely above 7000 unless you have changed ECU that will allow you to calibrate.

My 33 pulls 186mph at end of standing Kilometre with a lot more than 500Hp on tap.

DaveG

 

[radium69]

Thanks ATCO,

I will be planning to use a Halltech Pro.
So I foresee no complications.

Only problem is the 8000RPM out of a RB30 means the following:

- upgrade harmonic balancer
- upgrade rods
- upgrade pistons

Am I right?

 

[ATCO]

Whose RB30 you running? RIPS, MGT, OSG or one from the Go tuning shop as you are in Netherlands? (Nitto stuff is good) Or just standard Holden short engine?

If you plan on running more than 8000 definite harmonic balancer, forged pistons, rods maybe if planning on big power, certainly ARP bolts, also use Tomei pump, gives good pressure and takes the revs. Unless you plan on dry sump.

If you are going RIPS, Rob can advise you what is 'needed' and what is 'nice to have'. He does short engines at a reasonable price and from my experience and others his work is some of the best.

I would expect you to get more than 500HP by the way, unless you are using about 1.2Bar boost on mickey mouse turbo.

 

[radium69]

Hello Atco,
Probably standard, but may want upgrades because of harmonic balance.
8000RPm is max.

I've spoken to Rob and he's a nice guy. Got some great tips from him.
He's the reason I got into RB30's.

About the power estimate, I will be running two stock Rb25DeT turbos at 1bar.

Cheers,