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Advice Needed On Drag Tires

iTzTMG

By iTzTMG,
in Motorsport Discussion & Builds

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iTzTMG Contributor

iTzTMG

Posted
Posted

I’m in need of some advice regarding tires/wheels for dragracing, as dragracing Skylines isn’t that popular in the Netherlands I figured I’d post here in the hope you guys can help me out.

As of now the specs on my car are:

Stock spec 2 RB25det

Stock turbo

Tomei poncams

Boostcontroller set to @11 psi

3 inch frontpipe, decat, Apexi 3 inch catback

RSP/Bell’s stage 1 ECU

FMIC

HKS filter

We don’t have a dedicated dragstrip in the Netherlands, so most races are held on an airfield or on the straight of a circuit.

For the bigger events the “track” gets prepped but even then I seem to have problems running the times that I feel I should be able to run.

My best time for now is a 14.4@98 mph with a 60 ft of 2.3 which in my opinion is not up to the potential of the car.

I feel that I should be able to get some better times if I get my 60 ft times down but for that I would need to get some decent tires on the car, currently running my 18 inch wheels with 265/35’s

From reading a bit it seems that the MT ET streets are the way to go, I just don’t know which size to get.

I’ve been looking at the 255/60/15 and 255/50/16, the 16 inch being closer in overall size to what I’m currently running but which one would be better?

And would the stock R33 GTST wheel be adequate to run the 255/50/16 MT Streets?

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JAS-25T Grand Master

JAS-25T

Posted
Posted

get some R32 GTR wheels if you can to fit 255's

Should be able to dip into the 13's with MT ET's. Though 98mph sounds like you're not getting value for money with your mods.

I did a similar time in my old R33 GTST with road tyres. dipped into 13.8 or 13.7 with MT ET's, with only boost, and exhaust.

iTzTMG Contributor

iTzTMG

Posted
  • Author
Posted

Thanks for that, so 16's it is.

I'm not sure why my mph is so low, I did about 7 runs during the weekend and on 4 or 5 of them I ended up with a 14.7 @ exactly 157.21km/h each time which is about 98-99mph.

Like you say, I'm not getting value for money with my mods right now, compared to other Skylines I've driven it feels a bit tame.

I'm planning to do a boosleak check soon to start "troubleshooting"

Should I start stocking up on axles too when running the MT ET's :laugh:?

iTzTMG Contributor

iTzTMG

Posted
  • Author
Posted

Thanks guys!

More power will be coming soon, saving up for a standalone,turbo, injectors and fuel pump right now.

Clutch is already changed for Nismo Super Coppermix kit

The ecu is a stock ecu with a flashed chip by RSP in the UK, nothing fancy but gets rid of the flat spot when turning up the boost.

XRATED Veteran

XRATED

Posted
Posted

As above... 98mph trap- your down on power or there is some funky gearing/ratio's going on. Plenty of people have run well into the 13's with stock turbo's.

For the kind of power your looking at, get a drag radial with a slightly lower rolling diameter than your 18's.

Diff, axles, half shafts and cv's are all fine.

J.

iTzTMG Contributor

iTzTMG

Posted
  • Author
Posted

Thanks!

Good to hear that the drivetrain should be fine.

13’s was what I was expecting to run, so I was disappointed when I only managed to run mid to high 14’s all day.

The gearing is all standard as far as I know, the car was completely stock when it arrived from Japan.

On the ¼ mile I have to shift into 4th gear just before the finish.

I’ll be checking over the car the coming days to see if I can find out why it’s low on power.

Already ordered some new intercooler piping, as the current setup uses too much hose clamps and silicone joiners.

Also need to do a pressure test as I suspect that the bov is opening when on boost.

Hopefully it'll be fixed soon and run some good times with decent tires on it

JAS-25T Grand Master

JAS-25T

Posted
Posted

Don't shit over the finish line, bounce the limiter if you have to for a fraction of a second. Just back off or shit after the finish line.

Stock BOV has a little hole in it that "leaks" to keep the transition between on an off boost smooth instead of hard on off.

Tyre's alone should see you do at least a 2.0 60ft and get you into the 13's.

Super Drager Mentor

Super Drager

Posted
Posted

Mate it seems you have bigger issues than what tyres to choose, your car is running similar times and MPH to what my non turbo 300ZX ran on $70 tyres. My bet is your CAS may not be set to 15* or something in your setup is restrictive as hell.

nemz.jpg

iTzTMG Contributor

iTzTMG

Posted
  • Author
Posted

Thanks, I’ll add checking the timing to my list.

The current tires are worn out and need to be replaced, so might as well get some good tires on there right away.

Not sure where I should be looking for a restriciton though, exhaust is 3 inch all the way to the back except for the the turbo elbow which is stock.

Intercooler and piping is free off rags/newspaper or whatever could be stuffed in there.

XRATED Veteran

XRATED

Posted
Posted

Get the car to a good mechanical standard.

Replace the stock front pipe, dump pipe, down pipe.

Correctly install better intercooler pipe work... I'd bet you have multiple boost leaks.

Get it on a Dino.

J.

  • 10 months later...
iTzTMG Contributor

iTzTMG

Posted
  • Author
Posted

Using this topic again.

I've now changed my intercooler, piping, checked the timing and managed to run a lower et of 14.2 @ 159 km/h while pedaling it in first.

Got the R32 GTR wheels and I am now looking to buy the MT's but it seems that the Mickey Thompson ET Street Radial Tire - 3793R is discontinued.

The replacement is the Mickey Thompson ET Street S/S - 3460, which is a steel belted tire, so it has a stiffer sidewall.

Are you guys still able to get the old model or are you running the new one and does anyone have any feedback on the new tire.

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