Drag Tyres On A 25t

[Lithium]

Hi guys,

I had been intending on saving money and getting any oil control issues sorted with my ECR33 for the drag season then getting some drag radials but I have been last minute offered the use of some MT ET Streets for a drag meet this weekend, and my warrent runs out after that at which point the car will be off the road for a while doing things so could easily be the last chance to race it in quite some time.

Has anyone raced their R33 GTS25ts with drag tyres without doing sump/head restrictors/breather mods? I am running 1bar of boost, stock rev range on a GT3076R on an RB25DET. All I want to do is cut a 12.xx before I take the car off the road, which is next to impossible on street tyres on the strip I race at. Is it likely to be suicide trying sticky tyres - even with highish pressure (for cross plys) to stop it being too severe on launch that I have problems, or have people done this without issues?

I am always watching the oil pressure gauge/light/everything like a hawk when I race so I'd notice if there is any issue straight away, but its worth knowing how stupid or not worth worrying about doing this would be.

Any input would be greatly appreciated

Cheers,

Dan.

[2BNVS]

you be fine, run the M/Ts 16-18psi

[2rismo]

Ben, ET Streets are a grooved slick (crossply, not radial). You're thinking of ET Street Radials - different beast.

Lith, a launch is a launch is a launch. It's only G-forces and you won't have any oil pressure problems just from a drag launch. Seriosuly, it wouldn't even cross my mind as a concern.

I would suggest you also use crossply front runners with the ET Streets though as radial front/crossply rear can have disastrous consequences.

[2BNVS]

ahh yep lol forgot that

[Lithium]

Awesome thanks for the feedback guys Fingers crossed might have some fun times this weekend.

[2BNVS]

its andra rules if u run crossply rear u gotta have the front runners isnt it 'Drain?

[Lithium]

its andra rules if u run crossply rear u gotta have the front runners isnt it 'Drain?

I believe here you don't have to have front runners, though it probably keeps things a bit more sane especially if you have a fast car. I know countless who have run crossply rear/radial front with no issue at all - drag radials have not caught on at all in NZ... which is why it has been so hard for me to sort anything out there. I intend on doing some trend setting however.

Here is a vid of a mate of mine in a fairly stock S14 doing a 12 on crossply/radial mismatch:

[2rismo]

I believe here you don't have to have front runners, though it probably keeps things a bit more sane especially if you have a fast car. I know countless who have run crossply rear/radial front with no issue at all - drag radials have not caught on at all in NZ... which is why it has been so hard for me to sort anything out there. I intend on doing some trend setting however.

Here is a vid of a mate of mine in a fairly stock S14 doing a 12 on crossply/radial mismatch:

If you go quicker than 12.500 on the quarter ANDRA say you need to have crossply fronts too. Check with NZDRA (if you run at an NZDRA sanctioned track) to see if their rule is the same.

I wouldn't do it in any case but if you're only going to run high 12's @ 110mph it shouldn't be a problem.

All I can say is that I've seen slower cars have issues and faster cars not so it's a bit of a mixed bag.

[Lithium]

If you go quicker than 12.500 on the quarter ANDRA say you need to have crossply fronts too. Check with NZDRA (if you run at an NZDRA sanctioned track) to see if their rule is the same.

I wouldn't do it in any case but if you're only going to run high 12's @ 110mph it shouldn't be a problem.

All I can say is that I've seen slower cars have issues and faster cars not so it's a bit of a mixed bag.

I would hope if you are sensible about it there shouldn't be any problem, I can't see it suddenly spinning in a long wheelbase stable whale thing?! I am aiming for high 12s @ 110mph though strictly speaking I guess it should be more than possible that the 12.5s mark could be cracked.

Thanks for the input anyway, I'll do the first run gentle to get a feel for it and see how it goes

[Lithium]

Well holy crap, the problem I had is not one I expected completely. First (and only) run I lined up with the intention of giving it a real soft run to see what oil pressure/car/everything felt like.

Ran tyres on 20psi, turned boost down to pretty much wastegate pressure (12psi creeps to just under 1bar), did a decent burnout and launched at 6000ish rpm with a reasonable amount of throttle and was fairly gentle on shifts etc just to get the feel for the radials/crossply combination etc.

Ran a 12.8 @ 110mph with a 1.9s 60ft, but on the launch the tyres touched the guards quite convincingly. Given that I gave it a gentle (read: bogged) launch there is no way even rolling them a bit with the rudimentary tools we had around was going to give sufficient clearance for if I committed to a hard launch. DAMN damn damn, I can't believe how easy the 12.8 was given how long I've wanted to get a 12 - the damn tyres made it feel like such a huge non-event. I am really confident that if I was running a full 1bar and just gave it the welly the whole way it would have got a low 12.

Oh well, parked car up and got the daily driver down for a few runs instead so the Skyline came home in one piece and I will sort out a fix for the guard bumping situation. The Honda did a 14.6 @ 95mph, looking like it had taken a wrong turn on the way to the dairy haha. Fun day

Edited November 22, 2008 by Lithium

[2rismo]

Great work on the 12 but what dimension tyres were they and what wheels?

[Lithium]

Great work on the 12 but what dimension tyres were they and what wheels?

Cheers - it was rather effortless lol, made it seem so cheap.

They were 26x11.5x16s, not what I would have gone for width or type wise (already solid on the MT ET Street Radials) but someone called me that week and said he wasn't going to be racing and would like to see how mine would go with them - offer I couldn't refuse. I put them on R32 GTR rims.