Not my local track. I am down visting my brother in OK. Local guys say this track sucks, but I don't really know. It was thunder valley raceway in Noble OK.
I could not get out of the hole for $hit. Tried my low rpm launch but just bogged really bad, and a 2.5K rpm launch gave me bad wheel hop.

Here is a couple slips to give you an idea of how things were

60' 2.265

330 6.245

1/8 9.503 @ 73..88

1000 12.331

1/4 14.709 @ 95.07




60 2.299

330 6.290

1/8 9.533 @ 75.01

1000 12.349

1/4 14.716 @ 95.49



I did not really expect to run real fast, but I thought I would get at least a 14.4 or 14.5. I tried to find the elevation online of Noble, OK compared to Byron, IL but had no luck. Can anyone find out for me? My trap speed was real slow. Last October I was getting 98-99mph traps and 14.2's all day.

I think it was a combination of the following betwen my last time out

1. different track
2. 20 degrees hotter
3. kept my passanger seat in
4. elevation
5. 60 foot times

My brother ran his s13 sr20det and ran a best 13.86 @ 100mph. That is on the stock T25 @ 1 bar, 3' down pipe back and FMIC.

 

Welcome to my world buddy. I have a few friends that have run at Thunder Valley and they describe the track (traction wise, ET/MPH wise) as being exactly like our local track, KCIR. Thunder Valley sits at about 1300' which is about 100' higher than where I run. As for the launches, the traction problems sound exactly like my track and your 60 foots are right in line with what I get. Let me guess, you launched at 2500-3000rpms and got some fairly bad spin that turned into some pretty decent wheelhop thru most of 1st?

I wouldn't worry about it too much. I doubt there is nothing wrong with your car. Some tracks are just quicker than others.


Dave

 

why is your bro running i bar on a T25? that is way out of that turbo's effective range. he's just going to blow up those journal bearings, fast. 12, maybe 13 psi is the most i would run, esp on stock injectors/maf. i hit a 12.9@107 on a T25 on my SE-R @ 10 psi, so something has to be going on there (and altitude wont affect a turbo car that much). most 240s weigh only about 2600-2700 lbs with an SR20 in them, so the extra 100-200 lbs wont make that much of a difference. he should be about 103-105 mph.

 

hey, this is Mikes Bro. Just wanted to reply on your comment. I agree 1 bar is pushing it a touch but LOT of people run the exact same set-up and pressure as I do. Get on FreshAlloy and look around - it is very common. I am running a dynotuned SAFCII, Walbro 255, 300zx MAF, Blitz LM FMIC and 3" turbo back Blitz exhaust. I am probably putting down about 230whp. Also, as far as the t25's "effective" range. Show me a t25 compressor map. I'd like to see it - good luck though cause none has ever been published.

As far as my times, I don't know what to tell you. 12.9@107 is great - props to ya. I am a little dissapointed on my times but I have only had this car to the track twice. I can't seem to get it all togeter in 1 run. I have trapped over 101 on a couple of occasions. Probably a combination of subpar driving, bad street tires, slow track, and I'm not sure my timing is 100% on. I'm not gunna make excuses though - I'll just try and do better next time.

 

I feel for ya Dave. I really don't want to blame it on the track.....but my car seems to be running fine. I'll be out at Byron April 17th, most likely with slicks so we will see what happnes then.

You know a good place to get elevations??

 

i have this information about T25s from a friend who works for Garrett, and he has access to the compressor maps. efficiency at that boost is somewhere in the low 60s, not good.

at a dyno day, on C16 (to prevent it from exploding more than anything) i hit 250 whp @ 13 psi. the injectors were MAXED out at 11 psi, and 100% duty cycle is not good for making power. this may be contributing to your lower trap speeds, as well as the extreme delta P you have in your cylinder head from making that poor T25 spin up 14.7 psi. i hit 243 whp @10 psi, so those last 3 psi were worth a whopping 7 whp. i gained about 18 wtq, but lost a HUGE amount of power past 6000 rpm, like 20+ lb-ft at every rpm when compared to the 10 psi run.

the main thing to worry about is the journal bearings. they arent meant to take those kinds of loads. i can almost guarantee bearing failure in not too many miles.

i dont trust the opinions on freshalloy.com. the popular belief there is that more boost makes more power, which is not true.

i have been tuning turbo SR20s for years now. do a search under my name at www.sr20forum.com and you might come across my name about 2000 times.

 

i dont know what to say ? hotter temps around here can really spoil your party. that passenger seat if its a big 45 pound leather one kept you from entering 14.6x .

throw in the elevation , and a new track and all this stuff sounds like it just beat up on you.

on the 240 with swap ? what tha ? i had no idea the swap would net such times ? i thought it was good for 14.5 but looks like your brother is really logging some awesome times.

 

should be able to hit high 13s on an S13 swap with stock boost and 3" exhaust.

 

if I would have pulled similar 60 foots I would have been at 14.4-14.5 and I bet the weather and altitude was the other couple tenths. Can't win them all.

 

Steve, Mike's bro here again. Can you get me a copy of the t25 compressor map? I'm not calling B.S. - I would seriously really like to see it. As far as the journal bearing, I'm not too worried. I'm wating to upgrade the turbo anyway (gt25R with 0.86a/r or maybe just a t28). I'm also not too worried about hurting my engine cause I am tuned to about a 12:1 afr across the board. I don't know what my duty cycle is though.

I definately don't know all there is about SR's so i'm willing to listen to any educated info. I may hit ya up on SR20 forum - and quit hyjacking the maxima boards - LOL. I've always thought of FA as the authority on SR's though.

 

unfortunately, its a proprietary map, and he is not allowed to publish it.

get the GT25R or a GT3037. the 3037 will have better response, but will require an external wastegate. its not too hard to do, you just someone who knows a lot about welding (it needs to be heated RED hot prior to welding, etc) to get it right without cracking. the GT25R uses an NS111 turbine, which flows to about 300 whp, after that, its a major choke point. the compressor is rated to about 400 whp, but the turbo is only as good as its smallest part.

pm me if you want on the sr20forums, same name there. SE-R guys have been turboing their SR20s since before SR20 swapped S13s ranked more than a dozen in the US.

 

Found a little vid on my brothers local nissan message board. Don't laugh I had a 2.366 60' on this pass.

http://nismokc.com/albums/videos/Deatchbros.wmv

 

Seriously though that sucks that you had bad times at the track. Did you run higher octane gas or just pump gas... I still think your car might have a crazy knock sensor.

 

Yhea it sucks. I never traped higher than 95 all day.

I put in a gallon of 104, but I already had a 1/2 tank of 91 (91 is all they have in OK). So I don't think the race gas did much except put me at my usual 93 octane. Most of the higher ET had to do with my 60' and the higher elevation I think.
I was going to run with the knock sensor resistor mod but I forgot bring the resistors with me. I plan on running the resistor in place of my kock sensor and race gas when I go to Byron in april. What I should do is do a couple passes w/o the resistor and some with...but I am worried that I'll trip a 0304 code and be screwed the rest of the day.

I just sold my 17's and got the stock Touring BBS mesh wheels with new potenza RE950's. I am shedding a total of 56lbs of unsprung wieght!

 

hey , just watched the video ! if you would have nailed your best time the 240 would have had some big trouble on that run ! LOL !

what i cant get over is how these 240's sound so lazy ? its sounded alot like some car taking a sunday afternoon cruise.

then the scoreboard pops up 14.1 @ 100 mph , to show that the 240 is hauling tail ! lol


real nice race ( i was pulling for you) i would also love to have a 240sx, that low sounding exhaust is much cooler than my nasty fart can ! lol

 

1 Gallon of 104 + 7 gallons of 91 = 92.6 octane

1 gallon of 104 + 8 gallons of 91 = 92.4 octane


So whatever amount of 91 you had in the car, if it was around a half tank, you weren't even up to 93 octane. That could be your answer right there.