Well to start off the temp was about 80degF and the tracks altitude is 2270 feet above sea level, with a full tank and my 6'7" 260Ibs fat *** in the car she weighs in at 3860Ibs.

Times with mods below is sig
Car makes 10Ibs of boost at 5500rpm

1st run
60' -- 2.089
E.T.---13.261
MPH--104.793

2nd run
60' -- 2.108
E.T.---13.217
MPH--106.574

3rd run
60' -- 2.156
E.T.---13.345
MPH--105.093

4th run
60' -- 2.173
E.T.---13.429
MPH--105.929

5th run clutch slipped all the way down the track
60' -- 2.167
E.T.---13.484
MPH--104.188

I was surprised my clutch didn't turn to butter after the first run, I was only expecting one run out of her tonight. On that last run the sun was on its way down and it started to cool down pretty good, seams to wake the car up, I just wish my clutch would of held in that last run.

Well what's your guys thoughts good or bad?

 

heh, that’s a heavy 3rd gen. FWIW, my formula is at 3710 with me, 6’4 and ~300#. How do you fit in the car? I found that with the hardtop I couldn’t put a helmet on so I modified the seat rails to sit about 1.5” further back then stock and slide down as you go back, so all the way back the seat bottom is on the floor and I have room for my head, but pull it forward and it comes back up and my wife can drive it.

Huh, well, to be brutally honest you’re running about .1 and 2mph better then I ran in my '87 formula 350 with nothing but a cold air and cat back, that was on at 87* but not nearly that altitude, a few hundred feet at most. You don’t know what the barometric pressure was (you can look it up on www.weatherunderground.com by location and time/date)? I’d love to see what yours corrects to, if you want you can use the correction equation that I usually use so that we’re talking the same terms, this one uses the same one:
http://www.prestage.com/Car+Math/ET+...s/default.aspx

What were you running before the blower?

With 10 psi I would expect to run about a high 11@114 or so, with your car’s 100# extra + 2000’ I’d still expect a mid/low 12 @ 110 or so…

 

Are most cars, 'hooked up', by sixty feet?

 

I got maybe about a inch of head room left with the seat all the way back, I don't think I'll be able to put a helmet on unless they let me run her with the t-tops off

Thanks for posting those websights I'll make sure I check them the next time I go out but to bad they wont let you see yesterdays temps and stuff for us canadians. I got a question for you though, is it the same for blower cars with altitude corrections?

Thats a pretty fast formula you got there to be trapping at those speeds, the most I ever got with out the blower was around 96-97 MPH up here.

Ya I was hopeing for at least close to a 110 MPH run tonight you would think but I guess it wasn't in the cards. I logged most of my runs and I had some knock I'll have to program out of her for the next time, but we will see what to make of her in the next few weeks.

And for contactpatch I don't know about other cars but I know this one was.

 

I just found another time slip under the seat, looks to be my second one of the night and my best run to.

2nd run
60' -- 2.108
E.T.---13.217
MPH--106.574

I think with this run is when I tried out a chip that was a little leaner.

 

Well, making some assumptions since you haven’t given the information, that this was a Friday night T&T, you’re your track is somewhere near the town you have listed:
Observed at Prince George, (History)
Lat/Lon: 53.9° N 122.7° W
Elevation: 2267 ft / 691 m http://www.wunderground.com/history/...lyHistory.html

And that since your fastest run was your second one, which I’ll guess was around 7pm, you were at 71*F and had a barometric pressure of 30.17, which results in:
Correct ET to Standard Conditions
ET: 13.217
MPH: 106.5
Temperature: 71
Barometer: 30.17

Results
Corrected ET: 13.211
Corrected MPH: 106.45

Wow, I wasn’t expecting that, since you’re about 2000’ higher then the typical track around here. (Man, I just looked at our weather at the same time and we were having a spectacularly cool day, averaging 8-10* cooler then normal, and we were at 79*, 29.89in and 94% humidity at the same time, the correction for which would have put you at running a little over .1seconds faster at 2200’ then I would here near sea level at 144’ (I checked the 3 local tracks and they range from 93, 173 and 800’, the one that is listed at 173 is within a mile of the weather station that I was checking))

Anyway, my point is that you actually had better conditions then some of us lowlanders, so your altitude isn't the reason

 

That's some respectable numbers if it's a basically stock 350 TPI with a blower. Them GTA's a are big fat pigs, aren't they? My brother's 87 GTA weighed over 3800 with him in it, too. Took a bit over 400 REAL HP to run 110.5+ MPH trap speeds in a rig that heavy. His times were all 13.0000000000000001 @ 110+ with either heavy spinning off the line or heavy spinning when he hit 2nd gear (street tires). Never did get it to hook up the entire track.

It takes a lot more HP to move 3800 lbs a quarter mile than it does 3200.

 

The 110mph + range is where I think he should be at, like your brother’s car. As far as ET, it is a lot more effected by driver’s skill so I could see that being all over the map from somewhere I the low 12’s to 14…

One place to look for better times once you find the hp (MPH) is the launch. I’ve run as fast as a 1.71 with a 6 speed and 1.80’s with an auto on street radials. These were both 13s cars and their 60 was limited by power/gearing/torque converter and not by traction (they could both spin their tires easily, but when “driven” out of the hole on radials the didn’t post slower times then they did with drag tires which could dead hook out of the hole).

I would expect getting your 60’ down to the 1.7’s would bring your ET down to about a mid to low 12 and your MPH should be just short of the 110 range. Assuming reasonable gearing I would expect that combination to be capable of low 1.7’s high 1.6’s on radials and as fast as 1.5’s on sticky tires.

The point being that you’re probably looking for about 2-4mph in tuning as opposed to the 8-10mph that it looks like you’re missing, the rest is in driving/chassis setup.

 

Very interesting indeed, I would never have guess that. Oh and thanks for posting the history, I think I got that figured out now. My second run was closer to 8:00 so looking back, my temps were at 78.8 °F and I had a barometric pressure of 30.15 in

Corrected ET: 13.182
Corrected MPH: 106.77

Getting a 1.7 is going to be pretty hard since they don't prep the track, I was hopeing my nitto's would have helped there.

Can you tell me a little more about what setups you've seen like mine that can get into +112mph, because I'am a little disappointed buy having a big blower and not producing.

Do you think my shift point and rpm when crossing the line makes a difference? Most of those runs I shifted at 5500 then cross the line at 6000 in fourth, for the first run I shifted at 6000 in all gears.

 

A few hundredths difference… Ok, still in the same range. Surprising that it got hotter as the night went on.

I’m not sure that track prep is that big a deal. It makes things easier isn’t a deal breaker. I know the track that I usually run on usually only preps the launch pad if at all, although in the last year they’ve started to get a little more serious about it trying to attract more heavy hitters.

The times I posted were from before then, when track prep was spotty at best.

It’s not that I’m comparing you to a specific setup, it’s just what you can expect from the conditions you described. Whether people want to believe it or not, if you take enough stuff into account you can calculate almost any of this.

To be honest, it’s somewhat hard to come up with a good comparison with an f-body, since it seems like people that have done something similar in them either never fully optimize them (or in a lot of cases even run them at the track), or if they do they end up going with a much more serious combination. I could compare it to something like my brother’s car but the combination is very different and most people wouldn’t see the comparison (302 ford, stock short block with a mild lunati cam, some TFS parts, an Eaton M-90 blower pushing about 8psi boost in a 4 door ford LTD, the car has run as fast as 11.2’s at 119 with a 1.60 60’, but if you compared airflow numbers you should be making just a little less power…)

I don’t think that your shift point should have changed much if at all from whatever it was before you put the blower on. The blower does not change the velocity/tuning in the intake, but the density of the air flowing through it. With more power you might run a little bit faster by shifting 1-2 a little later to prevent some wheel spin on the shift, but that’s about it. Unless you’ve done heads or cam on the car I doubt that you should be shifting much above 5200rpm for your fastest times. I know my formula 350 runs it’s fastest times with me shifting with the tach showing 4600rpm (the data logs show that either the tach or my perception is about 100rpm off). Even with the better runners/headers the stock heads become a flow restriction at somewhere between 4800 and 5000rpm, so I doubt that your HP peak is above that.

 

I used to shift at 5000 rpm for my best times naturally aspirated and surprisingly my tach is pretty close. At 4000 rpm right now I'am at 5Ibs boost and 5000 rpm it's at 8Ibs. The next time I go back to the track I'll try a few lower shift points and see where that gets me, my feeling is with the SS runners and intake my HP peak should be at 4800-5000 rpm NA and with the blower it will raise it maybe 300-500 rpm's more. Do you think I should shift into 5th also or hold 4th tell I cross the line? If indeed the lower shift points help then I might put on this other pulley that I have, it's a 3.4" and the one I have on now is a 4", just to give me some more power down low where I might need it most.

 

That sounds about right for the mods that you have… like I said, I’m shifting about 300rpm less then that with all stock parts.

Part of that is from the nature of the blower (the more rpm the more it moves until you exceed the efficiency range of the compressor), but part of that is because you’ve passed your HP peak and your VE is dropping quickly, so the engine is becoming a restriction to airflow faster and you see more boost because the blower is trying to move the same amount of air. Airflow = HP, boost <> airflow. Boost is actually a measurement of the restriction to airflow.

I’d expect 200, maybe 300 rpm, but no matter what you do, that engine will not like to rev with stock heads on it.

Wow, that’s a tough call. My ’97 WS6 with a T56, stock, with stock gears would run faster crossing the line in 3rd bouncing off the rev limiter for the last 50-100’ then it would if I shifted into 4th. In your case, 6K rpm is a lot of rpm for a stock short block, though I have wound them to 6400 (but didn’t feel good about it, well the data logs showed 6375, but diacom won’t log past that). 6000rpm in 4th with 4.10’s and a 26” tall tire should be about 113mph… I’m betting that you’re not crossing the second line that fast, so you may want to look into that slipping clutch sooner rather then later. If it were me I’d look into either 3.73’s, maybe 3.89/3.90’s in something like a 9” or taller tires at the track. I don’t think you’ll win either way (shifting or winding it up to 6K) long term, and 5th is an OD and not designed to hold any real torque. I own a set of 275 60 15 (slightly more then 28” tall) DR’s for just this reason.

Well, that 5-8 psi is significantly different then the 10psi that you said you were running earlier (I realize, rpm differences…). That pulley should increase your blower rpm by about 18%, and you’ll be moving roughly the same air at 4200rpm as you are now at 5000rpm.

If it were me I would try it, but then again, I’d be very careful about it. Honestly, for long term durability I’d stay away from >10psi boost (well, if you want to splash some race gas or toluline on it then go for it) and >5500rpm. Again, if it were me, I’d slap some 28” tall tires on it, put the bigger pulley on it and try some passes. I’d try shifting at 4600 rpm and crossing the line in 4th (115mph with a working clutch should be about 5600rpm with a 28” tall tire, should be about perfect since I’d be surprised if you saw 115), and then try raising the shifts about 100rpm per pass till you find your fastest pass or till your shifting at 5500rpm or boost is too high (I doubt that you’ll go over 5200rpm).

 

Hey thanks Mark this is some good advice your giving me I really appreciate it. Hopefully my clutch problems will be solved with the help of McCloud's street twin I just ordered, this SPEC stage 2 just doesn't like to be slipped at all with out it turning to butter the rest of the day. I thought that going with 4.10's would hurt me a little but I was looking more for drivability then anything else. Maybe I'll see if I can buy some used 9 bolt 3.73 for the rear and save the 4.10's for when I get some AFR heads and a decent cam later down the road.

Is there something I can buy to bleed off boost when I hit a certain number like 10 psi? Then I would feel a lot more comfortable running the smaller pulley.

 

Is there something I can buy to bleed off boost when I hit a certain number like 10 psi? Then I would feel a lot more comfortable running the smaller pulley. [/B][/QUOTE]


ati should have the correct pulley to get you in that comfort range, i mean i know turbos have wastegates but on a centrifugal blower i really dont know besides getting the corect pulley setup for what you want to do

 

I am yet again surprised at how similar the stock boosted L98s run, turbocharged or supercharged. This is at least the third person I heard running very close to the same ET/MPH as my TT IROC. I run 6-7psi and 3.70 gears in the 9 bolt rear, and I run into the same problem at the top end of the track. My best times were by screaming the motor to 6K in 4th (12.46 at 113), but my best MPH was obtained by shifting into 5th (13.000 at 117). The 117 run was on a cool spring day, but on street tires (the fastest ET was on drag radials). I was always curious if it was my small, restrictive turbos or the stock TPI intake/heads that caused my less than stellar performance (for a boosted V8 anyway). I'm beginning to think its the engine, not the turbo system.

 

Way to go Tony...Like has been previously mentioned, if you get a better launch, you should be able to make it into the 12's.

Seeing that your set-up is very similar to mine you should have no problem hitting mid to low 12's

Have fun
later
larry

 

Heh, which street twin? I own an aluminum flywheel one in my WS6, and contrary to what most people say, I wouldn’t recommend it to someone that is going to drive the car on the street a lot (unsprung hubs + relatively light weight makes for a touchy clutch pedal, it’s no fun in traffic, _everyone_ that’s driven it has stalled it pulling out of my driveway at least once). I do think that the steel flywheel one is fine for the street… (I’ve installed a few of them now, and to be honest, I liked the original, clutch rebuild version better then the adjustable MC version).

4.10’s are the gear of choice for an NA car running less then about 115-117 (obviously not with a TPI intake, I’d say under about 108 with a TPI). 3.73’s are better if you’re making more power then that, especially with a blower that will let you do it at a lower rpm. Like I already mentioned, I’m a big fan of tall tires at the track… not only do they fix gearing problems, but they absorb more energy and give you a much bigger useful contact patch.

Run what you’re comfortable with… who cares? Have fun. It’s not like this is an all out drag car that needs every last hp. My advice here is based on the fact that I’m more comfortable running more boost and less RPM on an engine that isn’t built up to turn the RPM. RPM will tear an engine apart; boost usually won’t unless you’re getting detonation.

When it comes down to it, you have more to gain right now from practicing driving and launching then you have with messing with the engine. I like to go to the track and practice, learn something new…, but in my case, I also see some merit in systematically blowing an engine up, to find exactly where the ragged edge is. Funny thing is that I keep testing that but have never brought an engine home in a bucket… yet.

You could run something like a formula style blow off/pop off valve, but I don’t think that I’ve ever seen one for that low a pressure and I don’t think that most of what is sold as blow off valves for turbos/blowers are accurate enough to use for the application unless you want to setup some sort of electronic trigger (say a hobbs switch set for a specific pressure that opens a gas valve that allows the blowoff to open)

 

I'll be running with the steel one forsure.

 

Well I made it back to the track once again but this time it was much cooler and I only had a 1/4 tank of fuel in the back, but no real changes since the last time except for lowering my timing a little to get rid of some detonation.

Temperature: 64.4
Barometer: 29.95

Here are my good runs that I didn't miss a shift on, next time I'am going to bring proper footwear

1st run
60' -- 2.115
E.T.---13.073
MPH--106.007

these next runs were all back to back

On this run I let the car cool off for a hour and a half because my clutch was slipping the run before
2nd run
60' -- 2.216
E.T.---12.998 Woot!! my first 12 second run
MPH--107.374

3rd run
60' -- 2.124
E.T.---13.090
MPH--105.754

4th run
60' -- 2.107
E.T.---13.122
MPH--106.068

 

nice runs .i can sure tell difference between autos and manuals by your times.it`s amazing the et`s u get with those 2.1-2.2 60ft.I trap the same speed as u but with a 60ft 1.83.there is no way i could run a 12.99 with a 2.2 60ft.hey could tell me your 330`,1/8 ,1000 times ,id like to compare it to mine.

 

Reaction--.576
60' -- 2.216
330'--5.699
1/8---8.535
MPH--86.923
1000'--10.954
E.T.---12.998
MPH--107.374