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Discussion Starter · #1 ·
Hi All...

At what 1/4 mile trap speed does going to a bigger (28") tire make sense. Right now I on Nittos 275-50's..which are a tick smaller that the stock Tire

TIA
Bob
 

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I'm hoping it's right at 110mph.


I bought the bigger Nittos but the track rental got cancelled and I may not get back there this year.

Really wanted to see some improvements with the new stuff and colder air.
 

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Discussion Starter · #3 ·
I tried the 28" tires 2 weeks ago and went from 110 to 106..car ran well otherwise no knock 18-20lbs of boost...I was only off about 1mph in the 1/8th mile. I had the converter locked at 88mph. Im undecided as what to do for tomorrow...whether to try the 28" again without lock up...or to lockup at a lower speed say 75mph...or stick with the 26" tires.

As far as cold weather goes...it was about 35 degrees last week at the track....very tough to get the turbo to spool...especially with bigger injectors.

Bob
 

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We got snowed out. 1" snow in the Berkshires at LVD.

Really sucked.

I'd give them another shot. Kinda surprised you slowed down that much.


I was expecting to go to 212 mph just on the tires alone.
 

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For slicks, I would say about 116. For DR's, I guess it would depend upon the car. I cannot launch my Nittos at any boost. I would think the new ones that Salvage bought should work pretty good for most people so I am surprised you lost speed on the top end....was the car running fat?
 

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Discussion Starter · #6 ·
Hey Steve.....the car was running 800-785 with tlink..... but took a while to boost up as it started at 17 and finally hit 20lbs at the big end of the track. What hurt I think was locking the converter..it bogged things down a bit...the question is should I try the 28's again without locking up the converter or go back to the nittos.
 

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I'm going from Nitto to Nitto in the 50 to 60 series switch.
 

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well, the O2 readings don't mean much, IMO, but, if anything, I would say it was lean. I am not sure what was going on with the slow spool but you were only off a tenth in the first half. I would think the taller tires would create more load and therefore, more heat, so I would think spool would be better.

I would try the tires again without the lock. At that speed, I would not think that the lock would have much negative effect so I will not be surprised to see a fall off, unlocked.

Normally, I think the taller tires begin to help around 11.7 or about 115-116 mkph as I said above. I would think they would be a wash around 110.

What rpm were you pulling at the line?
 

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Discussion Starter · #9 ·
Got back from track a while ago...And managed to get about 1 MPH better with the 28" tires. Going through the traps at 4600 rpm with the converter unlocked...Car bogged bad at the start because the spool was a bit lean...EGT's were 1599

Think Ill stay with the 26" for now

Bob
 

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One mile better than when locked?

Lean at the line should help the spool...more heat.....now if you were so lean that the car would not make hp, that's another thing... *s* sounds like you have an issue or two to me.
 
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