[GAPZLA]

Hey All,

keen for some feedback.

I went to the strip last night, just could not get decent traction or launch (I’m on Michelin pilot super sports) 28psi front 25psi rear for the strip.

First run I launched on R C off at 4100 and car went sideways 1.5m. Backed off

2nd launch R C R with a 3600 launch spinning and a tiny bit sideways with some wheel spin before getting traction - it’s funny because a few months ago I did consecutive 3800rpm launches at GTR festival and it just hooked perfectly every time. (This was 3800rpm R C OFF during GTR festival)

final run RCR 3000rpm got me the 10.66 but a terrible 60ft and I’m sure I still had some wheel spin or could be bunny hop have to review the video.

coldish night here in Sydney And also rained the night before (not sure what sort of prep they did after the rains the night before but surely there would have been some during the day before they opened for racing - may not have been the best prep though not sure….) and I was on e79 (reading off the Cobb)

for reference there was about a 15-20min wait between runs as well and not much opportunity to keep tyres war

The draggy from my best run when I could put the power down, data in kmh (136.51mph for reference)

Vs when I was getting traction and on e60 a few months back:

looks to me like I can get a 10.1 or 10 flat if the stars align which would be pretty good for an fbo e85, however based on the testing last night and my traction issues it looks like I have to go drag radials to achieve that.

There’s still a bit more power in it if I can get it to e85 up from e79 lol

mod list:
Full exhaust
Partial intercooler piping top side
Cobb flex tune
Injectors
Pumps
Carbon intakes
Full Dodson gearset, clutch packs, with a mix of extreme and heavy duty gears
SPL Traction Rods

I left early as it wasn’t working for me so decided to wait for another day video coming shortly if people want to see

 

[GAPZLA]

Video - my phone kept flying off so had to overlay the draggy on a different camera lol

Watch this story by Shaneil | Sydney, Australia on Instagram before it disappears.

instagram.com

 

[L.L.]

Track prep is going to make all of the difference in the world and it's not always great at most tracks outside of major events. There is definitely some room for improvement with the 60ft times and that wheel hop is causing the bad 60ft times along with the phone flying off the holder. Had the same issues previously with my phone and that is my gauge to whether my launch was good or bad.

Are you running any BOTL and what size Michelins?

I find that my rear tire pressures need to be about 15-16psi with 23-24psi in the front tires while at the our local track to get anything in the 1.5x range. That's with a 3200-3300 RPM launch with 1.3 bar BOTL. If not, it is all wheel hop or traction control intervenes and resulting in a 1.7-1.8 60 ft. Here is a video with 9.91 pass at 7500 ft DA with the aforementioned settings. It yielded no wheel hop and just a little bit of spin even with TC completely off (off in EcuTek too).

 

[droptopp]

Can’t see your pictures (Thanks to GTRLife Admins and Tapatalk and their consistent issues) but if the dragy is showing 136mph, that’s probably 132-133mph at the track. That’s a 10.6 mph for our cars, so your actually not going to do much better than that imho. You’ll need to get the trap speed up to 137-138 for that 10.1.

Your main issue is the tires, they are rocks at 300+ UTGQ rating and your 1/4 time is pretty much boiled down to your 60’ on a stock turbo car.

Every track is different, but I’d get the rear tires down to 24-25psi and see if that helps, doubt it will much though.

 

[GAPZLA]

Track prep is going to make all of the difference in the world and it's not always great at most tracks outside of major events. There is definitely some room for improvement with the 60ft times and that wheel hop is causing the bad 60ft times along with the phone flying off the holder. Had the same issues previously with my phone and that is my gauge to whether my launch was good or bad.

Are you running any BOTL and what size Michelins?

I find that my rear tire pressures need to be about 15-16psi with 23-24psi in the front tires while at the our local track to get anything in the 1.5x range. That's with a 3200-3300 RPM launch with 1.3 bar BOTL. If not, it is all wheel hop or traction control intervenes and resulting in a 1.7-1.8 60 ft. Here is a video with 9.91 pass at 7500 ft DA with the aforementioned settings. It yielded no wheel hop and just a little bit of spin even with TC completely off (off in EcuTek too).

my front tyres are 285 and rears are 295 Michelin Pilot Super Sports. I’m not sure if letting those down to under 20 psi would be that great. I notice on your video (cracking run btw) you had Nittos I hear they generally do really well at those psi’s.

tbh I’m not sure about my botl setting is it possible to check through Cobb or gotta ask tuner?

 

[GAPZLA]

Can’t see your pictures (Thanks to GTRLife Admins and Tapatalk and their consistent issues) but if the dragy is showing 136mph, that’s probably 132-133mph at the track. That’s a 10.6 mph for our cars, so your actually not going to do much better than that imho. You’ll need to get the trap speed up to 137-138 for that 10.1.

Your main issue is the tires, they are rocks at 300+ UTGQ rating and your 1/4 time is pretty much boiled down to your 60’ on a stock turbo car.

Every track is different, but I’d get the rear tires down to 24-25psi and see if that helps, doubt it will much though.

136.51 was from the time slip not on draggy. Not sure what the mph would be if I converted what’s on draggy. And if I can remove that bunny hop for sure it would be 137-138 or so. And dial it in for a smooth launch.

rear tyres were already down to 25psi. Could try 23-24 but not sure how much it would help if any.

 

[alexdavis]

<SNIP>

I find that my rear tire pressures need to be about 15-16psi with 23-24psi in the front tires while at the our local track to get anything in the 1.5x range. That's with a 3200-3300 RPM launch with 1.3 bar BOTL. If not, it is all wheel hop or traction control intervenes and resulting in a 1.7-1.8 60 ft. Here is a video with 9.91 pass at 7500 ft DA with the aforementioned settings. It yielded no wheel hop and just a little bit of spin even with TC completely off (off in EcuTek too).

A quick question: I've never experimented with big differences between front and rear tires; I'm thinking 23-24 against 15-16 is a big difference. The question is (and apparently you're not seeing it) does the car react in some other funny way with this sort of difference...maybe going into Limp mode or something?

Alexd

 

[L.L.]

I’m not sure if letting those down to under 20 psi would be that great

tbh I’m not sure about my botl setting is it possible to check through Cobb or gotta ask tuner?

Other owners have told me to run wheel diameter minus 2 psi from the get-go. That's exactly where I needed to be as that's where the car stopped wheel hopping. I have also done the same with the 20" R888R as they will hop if they're left at anything higher than 20 psi at the track.

I essentially wasted a couple of track sessions by not initially wanting to drop the pressures that low so I experimented by dropping in increments. I really should have listened as the advice seems to be sound based on the outcomes. Now I just simply start at 16 or 18 psi in the rear tire depending on 18" or 20" setup.

It's been years so I don't recall how to check BOTL for Cobb. Maybe Alex or Droptopp can chime in there.

A quick question: I've never experimented with big differences between front and rear tires; I'm thinking 23-24 against 15-16 is a big difference. The question is (and apparently you're not seeing it) does the car react in some other funny way with this sort of difference...maybe going into Limp mode or something?

The main thing is TPMS lights will be on all of the time but no limp mode. I've done both digs and roll racing with those differences in pressures up to 147mph trap and nothing felt funny. Now if you did that with bias ply or slicks, that might be a different story but we're talking about radials and I never felt like it was an oh sh-t moment. 😅

 

[GAPZLA]

Might give that a crack so would be 18psi effectively at the rear and fronts I might try with 20psi first.

how does the car feel at speeds with such low tyre pressures? Do you get that floaty feeling?

I’ll have to source some nitto nt05r’s or equivalent Mickey Thompsons for the rears - if anyone knows where I can get them that will ship internationally that would be appreciated. No stock available locally and back order until January 2023 at the moment haha.

outside of this - would it be much better to run front and rear drag radials or is just rears the common thing to do?

 

[L.L.]

I haven't experienced the floaty feeling with the lower tire pressures. Just keep it straight and don't try to take corners at speed. Air back up to normal pressures before heading home.

Don't know that it's necessary to get the pressures down to 20 in the front. Seems to be okay at 24 psi for all of my track sessions thus far.

 

[GAPZLA]

I haven't experienced the floaty feeling with the lower tire pressures. Just keep it straight and don't try to take corners at speed. Air back up to normal pressures before heading home.

Don't know that it's necessary to get the pressures down to 20 in the front. Seems to be okay at 24 psi for all of my track sessions thus far.

awesome thanks for all the input and advice! Few things to try out but I think I will commit to a set of front and rear 18’s with drag radials all round before the next time I go out.

By then I might even have my motec and a couple other things installed so could potentially go hard for a 9.99

Btw if you check the video I posted you can actually see the floating at speed - this was on 27/28psi front and 25 rears where the car was moving slightly left and right and took some small corrections to keep straight.

 

[L.L.]

I went back to check the video but the story must have expired.

The Motec TC and 18s will help get the times down. Once the 60ft is dialed in, shoot for a 6.50 or better 1/8 and you should have the 9.99. GL!

 

[droptopp]

136.51 was from the time slip not on draggy. Not sure what the mph would be if I converted what’s on draggy. And if I can remove that bunny hop for sure it would be 137-138 or so. And dial it in for a smooth launch.

rear tyres were already down to 25psi. Could try 23-24 but not sure how much it would help if any.

View attachment 403961

Gotcha, a 136 should get you to the 10.3 range. You’ll need 138 to get to a 9.9-10.1 with a 1.5x 60’ or better.

The tires probably won’t get you the 60’ you need.

Swap to an 888 and should have no issue hitting your goal. I’d probably run the 888 at your power levels (at 25-26psi so your light doesn’t come on over a drag radial.) You will float with drag radials, but it’s not bad. 888s have a very stiff sidewall and you will still maintain the ability to carve corners.

The 888 with Cobb with get you consistent 1.5x on the street once dialed in. Not much going to come around you once it’s dialed in without a burnout and a bunch of VHT lol.

Good luck.

Check STM to Cicio - think both have 888 in stock.

 

[alexdavis]

Other owners have told me to run wheel diameter minus 2 psi from the get-go. That's exactly where I needed to be as that's where the car stopped wheel hopping. I have also done the same with the 20" R888R as they will hop if they're left at anything higher than 20 psi at the track.

I essentially wasted a couple of track sessions by not initially wanting to drop the pressures that low so I experimented by dropping in increments. I really should have listened as the advice seems to be sound based on the outcomes. Now I just simply start at 16 or 18 psi in the rear tire depending on 18" or 20" setup.

It's been years so I don't recall how to check BOTL for Cobb. Maybe Alex or Droptopp can chime in there.


The main thing is TPMS lights will be on all of the time but no limp mode. I've done both digs and roll racing with those differences in pressures up to 147mph trap and nothing felt funny. Now if you did that with bias ply or slicks, that might be a different story but we're talking about radials and I never felt like it was an oh sh-t moment. 😅

Thanks! I'll try it next time I'm out.
Yeah, the TPMS light stays on; that I've seen.
All of this is at BOTL zero right?

Alexd

 

[L.L.]

Thanks! I'll try it next time I'm out.
Yeah, the TPMS light stays on; that I've seen.
All of this is at BOTL zero right?

Alexd

Since you'll be launching with the Michelins, zero BOTL might be a good starting point to see how it responds. I've been launching with 1.3 bar BOTL (19 psi) which seems to get the job done from about 3200 RPM.

 

[GAPZLA]

If anyone can chime in on how to check or adjust botl for Cobb that would be awesome.

I won’t have Cobb for much longer But would still be good to know.

 

[GAPZLA]

Gotcha, a 136 should get you to the 10.3 range. You’ll need 138 to get to a 9.9-10.1 with a 1.5x 60’ or better.

The tires probably won’t get you the 60’ you need.

Swap to an 888 and should have no issue hitting your goal. I’d probably run the 888 at your power levels (at 25-26psi so your light doesn’t come on over a drag radial.) You will float with drag radials, but it’s not bad. 888s have a very stiff sidewall and you will still maintain the ability to carve corners.

The 888 with Cobb with get you consistent 1.5x on the street once dialed in. Not much going to come around you once it’s dialed in without a burnout and a bunch of VHT lol.

Good luck.

Check STM to Cicio - think both have 888 in stock.

r888r is very hard to source locally in Australia at the moment due to supply and demand. There’s scalpers out there trying to charge $1500 for a pair…

I could easily get my hands on some nankang A1R’s which run about $480 per corner.

thoughts on using semi’s at the front and drag radials are the rear? I could run A1r fronts and Some Mickey Thompson rears

will there be any Instability or would this work just fine?

The alternative is just to use semi slicks on all 4 and see what happens…

 

[droptopp]

With DR at the rear only, it floats a bit at speed. If your track is old and grooves pretty deep can get sketchy at the finish line.

Just don’t jam on the brakes and should be fine lol

 

[GAPZLA]

With DR at the rear only, it floats a bit at speed. If your track is old and grooves pretty deep can get sketchy at the finish line.

Just don’t jam on the brakes and should be fine lol

perfect - just bought some 18x12 rears to run 345 mickeys with semi slicks on stock fronts.

have some more rims coming soon for street use luckily so won’t prematurely wear the semis or the drag radials for no reason.

 

[droptopp]

What’s a semi slick ? Never heard that term.