[griffous]

Hi All,

I need some advice from those that have been in a similar position.
I have developing my R32 GTR over the past few years with various upgrades along the way, including an engine rebuild.
As happens to many people I imagine, it started life as a road car, but after the engine was rebuilt/upgraded/tuned, it became clear that I wasn't going to be driving this car on the street safely. It was just too fast.

So I got into racing at the local race track (Pukekohe). This was great fun, I upgraded various bits as I went along, and in the car's current state I'm running 265 Semi-slicks all around and putting 400kw to the rear wheels.
Racing of course uncovered cooling and traction issues, most of which are now resolved. All fun development, but the car is still a full interior road car. I drive it to/from the track with the radio and aircon blasting, other then the tyres you wouldn't know any differently.

The astute among you will have noticed that I haven't mentioned my brakes yet. Yes, they are a problem. I'm using very aggressive Endless pads, with brake ducting, but it's still very easy to overheat the brakes.

This can also be solved simply enough ($$CHING$$), but at some point one has to realise that the package would go a hell of a lot better all around if the thing was lighter. Also this road car is really crossing the line here. I really need to just accept that I want to race, and the GTR is just too good of a car to crash, buying an old GTS-T would be much better all round for thrashing around a track. If I crash it, I just get another shell....

I know many skyline teams here race using GTS-T's for their weight. It makes sense. I also don't have rollcage in my GTR, and given the speeds I'm hitting now, I really should do.

So, I'm wanting info on making the switch. What do I need to know about GTS-Ts as someone who really only knows a bit about GTRs? For that matter, given that I'm changing engine anyway, will a GTS work just the same? It should be cheaper!

I'll be wanting to move my motor/computer across of course, and my wheels & tyres.
Gearboxs & Diffs, can they handle this level of power. I'm guessing I couldn't fit the GTR gearbox even if I wanted to run it RWD.
For fitting the wheels, am I going to have to get really creative with the gaurds to fit something suitable to put the power down?

What are the other differences that I should be aware of before heading down this road? I'd love to hear from anyone racing their GTR/GTS-T.

Thanks,
Gr|ffous

 

[SteveN]

Only read advantage to a GTR is also what makes it heavier, the 4wheel drive setup.

If you can live without it, ie you will be able deal with the less traction given, then go for it.

If its a slower tight and twisty track that you need the cornering speed and punch out the corners, you run on road legal tyres, or you race in the wet a fair bit, id stick with the GTR, as looking at the Time Attack series in the UK, the 4wds all seem to have a fair advantage, tho its much closer at the fastest of tracks in good conditions.

But if its a track thats more about power and you can run slicks etc then the RWD option is worth considering as traction wont be such an issue.

Is this competitive racing, or just track days?
As if its just caning round a track for fun, then id prob go for a GTST and build it to a fun setup, as quicker lap times dont mean more fun, thats for sure.

 

[griffous]

Thanks for the reply SteveN,

The track here is a high speed track, the slowest corner is around 80km/hour, the faster ones are around the 170km/hour mark. On the back straight I get to around 260.

I'm not really sure what driving RWD is like (I REALLY must get around to installing *that* switch), but I figure that everyone else seems to manage, I'm sure I'll get used to it, given the other benefits.

I'm racing recreationally (yes, track days etc) for the moment, but it would be nice to be able to develop the car further if time and money allow. I won't be on road tyres, and I won't ever race in the wet.

So other then the 4WD and the wider arches, what else am I sacrificing. The drivetrain has be a bit nervous.

Also on the braking front. I finished off my discs on Saturday. If I do upgrade the GTR's brakes, can I transfer them to a GTS-T ok later. Are the hubs the same - I'll be getting hats made, so I want to make sure they would go across.

Thanks,
Griffous

 

[anthonymcgrath]

suspension

well I dont track race my car its just a daily driver but its a gtst and I get out an about in it alot. Dont think anyone mentioned it but I'd suggest fitting adjustable suspension all around which you prob would anyhow but it'd definitely allow you to fine tune the driving quality on a rwd esp. if you've been using 4wd for so long.
I have had the rear suspension quite stiff since I got the car and its been that way thru summer. However the back end always felt REALLY skittish in the rain or wet roads esp. if the car came on boost. I got under it earlier this week and set it to soft all around and it was like a new car - ride quality really improved and cornering in the wet was amazing (compared to previously)
however - sunny hot day, tighten up the suspension and it sticks hard on corners again. It probably makes sense what I've said but my point is to def get adjustable for track day usage then you can decide if you want to really tighten up the rear and get into more drifting (I'm not a drifting fan myself - love seeing it being done but I like my racing lines)
btw I dont drive very close to my limits at all and every other NorthEast GTROC member will tell you I'm a pansy (last in line in a runout) but I like to think I'm slowly getting there hehe!

hope it helps just my (very limited) two penneth

 

[SteveN]

RB25 transmission is dead strong, so if you use that you will be fine (well at least as reliable as GTR tranny) with regards to it dying.

Wider arches arnt really an issue, as long as you not too worried about how perfectly tidy it is, you will be shocked how much wider you can get the standard arches with an arch roller/flarer, easy get GTS arches as wide as GTR ones, if not more so.

RWD driving is different, but with a well setup car, far more fun IMO, but maybe thats just me.
But it kinda depends what you find fun, if you like the more point n shoot driving of 4WD, you might find RWD to be no fun at all.

Lap times though, its generally easier to be faster in a GTR, thats for sure.

A GTST-4 might be a good plan, the GTRs 4wd, but a cheaper car...

 

[griffous]

How about the RB20 transmission, which I'd get with an R32?

How is the GTS-4 for weight and driveline strength - that did cross my mind, but I wonder how much better it would be for what I'm after. Cheaper though - I'll give you that
I would be assuming that the GTR ATTESSA is better/stronger in some way?

Thanks for the comments guys

 

[SteveN]

GTST4 transmission is pretty identical to GTR one, just lower geared diffs, which will help on what sounds like a fairly tight circuit.
They quite the bargain considering the transmission they come with.

RB20 gearbox in the R32GTST is far from great, way smaller than a RB25 box, similar to a CA18DET gearbox, so not great if we talking well over 350bhp, wheras youd struggle to kill a RB25 box at almost any power, esp on the track.

Id deffo be popping in a RB25 box, esp as its a direct swap.

R32GTST is about 1300kg i think, and R32GTST4 is 1380kg or so IIRC.
Obv a lot of that im sure can be removed with stripping it out etc.

You did say you like the aircon tho, but that does weigh a lot!

 

[griffous]

Right, so for weight savings then:
GTR: 1460
GTS-4: 1380
GTS-T: 1300

Given how heavy the rb26dett is, I wonder how much lighter the gts-4 chassis actually is....
The interesting point that I take from this is that I'm talking about only 80kg for 4wd, which really isn't all that much considering the benefits.

Heh, ignore the air con - that was to rub in how much my 'racing car' really is just a road car at present.

So what I'm looking for is a GTS-(T) chassis, but a 25T gearbox, all to be mated to a GTR motor? And they all just place nice when it comes to installing this combination? I understand I'll need to change the sump - which might be interesting considering I have a trust sump extention.... but other then that?

Optionally if I go down the GTS-4 road; I'll be looking at a cheaper chassis which will hurt the wallet a lot less if I crash it, and I still get to keep my 4wd. Plus by the time I strip it right out I'll still have a much lighter platform. So what do I need to consider for this conversion?

Gr|ffous