JMatlock88

I'm going to make a few passes tonight on street tires and without nitrous. This will be the first time the Formula has been out since the new motor. Any Oklahoma people planning to roll out? ***********

89ROC

Good luck at the track! Let us know how you do!

JMatlock88

Khumo 712 street tires, no nitrous

Best timeslip 12.922 @107.00 MPH
Best MPH 109.01

Everyone seemed to run slowly tonight. I know I know... Excuses. 60fts were in the 2.2 ranges.

I raced an LS1 vette with mods and slicks that was only running 12.90 even. I'll post some video of some of the runs if anyone is interested.

JMatlock88

Best ET timeslip

Quick6

Hey Jerod, nicely done, cant wait til you spray it.

89ROC

Yeah, post up the vidoes!
You should be a lot faster though. You NEED slicks. I bet you'd be in the 1.6 60-ft range with slicks. Then you would easily get a 12.0
If you didnt live so far, you could borrow my Hoosiers

JMatlock88

Ya, can't wait to run it next time with spray! I think that 109 MPH is good for some ~12.10's. Next time I'm at the track, I'm going to try a few more natural runs tweaking the base timing and the fuel pressure. I hooked up a gauge today and was only running 37psi of fuel pressure. I will try advancing 1-2 degrees also. The cold air pipe I hope will help as well. I never let the car cool down the entire time I was there. I think all of these issues will add up to some better times next time out! I'll get the vids posted soon.

Polecat

Darn good times Jarod.....wished I was there to see. I was on the cell phone all night back and forth with Dale to see how the 383 ran in his truck. He finally got a 13.53@100 MPH...and Adam was there with the '54...he's running solid 10.60/10.70's...so with a little giggle, he might see mid 9's...

Glad to see you got the car up and going strong...need those ET's Streets...

JMatlock88

Ya, it definetly needs some slicks! I'm looking for a set of fat/skinnies with et streets if you know of anyone around here.

I borrowed some tools from Adam to remove my nitrous bottle...tell him thanks for me. I didnt yet have my blow-down bulkhead drilled through the floor pan. They made me remove it even though I had an empty bottle with the supply line removed.

Do you think Dale is happy with those times?

Several guys from this site were down at the track that night which is pretty cool. They chose not to run their thirdgens though.

The car is still way too slow for 381 rwhp. To think I only gained 1 second from my previous time $3500 later.

Polecat

Yea, Adam may think he has a cam lobe going down again, so if it is, he may go full roller this time.

I think Dale is happy, but he sure wants low 12's....who doesn't, huh?

I am still having issues with my Holley 750HP, so it's been sitting since the last cruise night. So I am trying to find out where Holley stands on either swapping it out for another, or refund. But the waiting is just killing me!

I hope to send it off to the paint shop soon for a complete new paint job, and put my new aluminum radiator, waterpump and TCI tranny cooler on....so I'm having issues right now.

Yea, some skinnies and ET's on the back would look cool at the track, and on cruise nights....sure would put you in the solid mid to low 12's...then you can spray it! :hail:

Skweezn87

Ok .. Im lost here...

You're stating your car has 480hp/520ftlbs..but your only running 12.9's@107??

My measely 340hp car runs mid 12's@ 110 in the 1/4... care to explain where the extra hp has gone too?????

Rick

89ROC

That's his flywheel HP. He dynoed 381/433 to the ground.

TRAXION

Actually, 381/433 should trap significantly more than 107-109mph. Something else is wrong.

Tim

Skweezn87

Still... something's wrong... he should be in the 11's honestly w/ that kinda hp/tq..... I know of ppl w/ ALOT less do'n high 11's and in the teens mph... :shrug:

Rick

Polecat

Remember, this is on street tires, first run out.....

JMatlock88

Yep, the times ended up being significantly lower than I had hoped. I do have dyno graphs and video @ ed's shop to prove the ground #'s. My honesty is not the issue here I hope.

If I were, you think I would be reporting 12.90's?!

I would really like to know what you all have to suggest. I think the first thing is to get this baby on a scan tool and see if I'm seeing any knock retard. I have swapped distributers to an MSD since the dyno so the timing could be off. I used Ed's gun to set it while at his shop and my gun to set it after the distrib swap. (?)

Could a vaccum leak at the head/intake gasket interface lower performance? I suppose that is a possability since I had to remove the base manifold to mill it down for clearance.
My intuition tells me "no," but I'm trying to think of all the possablities.

What is normal gain for a totally heat saturated motor vs a cool motor? I have no feel for these type of gains since I'm still a young grasshopper. I ran the car right off the highway and never let it sit for the 4 hours I was running.

The dyno pulls were of course taken from the cooled engine, in mostly optimal conditions (October temps, low humidity, and a fan blowing into the intake)

Are there other variables that I have not yet considered?

I tried increasing the fuel pressure from 37 to 41 and realized a brief stumble @ wot.

I would appreciate your vetern input!

Polecat

I'm not as savy on fuel injected cars, but I think you have good times with street tires, no track tune time. The engine cooling would help in between rounds, but with aluminum heads, they disapate heat so fast, it really can't be too long. All I hear is you want to be up to 200+ temp at run time. And I know that track didn't have consistant 60ft times, or at least in that one lane.
With a 2.2 60ft, that tells me:
traction, gears or stall....for example, my darn 4200 lb truck on 28.2" ET Streets has 1.89 60 ft....so I see alot that can be made up right off the bat.

What RPM's are you at on the big end? That would decide what sized ET Streets to get...that's where I'd start...you could pick up alot with just that.

And I know you personally, as some of these guys don't, so I can vouch to anyone it's not your honesty.....

Skweezn87

So what if he has street tires.. I was running street tires too...big whoop!

Even w/ street tires.. his MPH should be helluva lot more..

Is your convertor locking up @ WOT?

Rick

askulte

Most street tire timeslips I've seen is a slow ET and fast(er) mph... Kinda like my old 12.7@114, he he he... I'm curious to see the dyno curve. Are you trapping near a shift point, or did you just shift before the lights? At WOT, there is no vacuum, so a vacuum leak disappears then. It might have sufficiently messed up the long term fuelling through the ECM, however... Dunno, I haven't touched an ECM since I switched to DFI. Good luck working out the gremlins.

A.

JMatlock88

Here is my dyno graph. Notice the HP and TQ curves have different scales. I'm not sure why it happened that way, but this is the printout that I scanned.

Is this THE Andris Skulte?
:hail:

Ed was explaining to me that my TC was locking up at 95mph during the dyno pulls. I did not verify that my TC locked up during the runs. The TC does lock up correctly under normal highway driving like it should, so I don't suspect any problems there.

All of the old guys were telling me that the best MPH would be realized on street tires. Slicks reduce MPH from what I am told. This further disappoints me.

Open up a can of worms, critique, and evaluate. I would appreciate any input on the dyno graph, and recommendations for improving the ET.

JMatlock88

I know my factory tach is off a lot above the redline since the tach was not designed to operate in that range. The factory redline is 5.5K! I really cant be sure for this reason what rpm I'm seeing at the finish line. What I can tell you is that the tach reads 6500 and it feels like it stops pulling before the finish line.
Does this mean I have too much gear or not enough tire? What drag radial tire height should I look for?
The current tire is 275-40-17 and the gear ratio is 3.73.

Skweezn87

Do you have the dyno run file??? I would like to take a look at it..

That is ONE "funky" look'n graph.... I am having a hard time w/ that hp from 5600-6000 (30 hp ) jump seems lil off to me...

What kinda convertor are you using and stall ??

Thanks

Rick

85MikeTPI

iTrader: (2)

What shift points were you using? At the bottom
of my HSR dyno test page, I include pictures of
the ALDL scans during the dyno and at the track.

http://www.eecis.udel.edu/~davis/z28...age021105.html

I got in 4 runs at the track that day testing various
shift points, and the HSR seemed to like shifting at
~6400 the best and had me crossing the line close
to 6300. Your tire sizes and gears should be fine,
just need to get those 60' times down and keep
a recording scan tool on during the track testing..

My factory tach is off by about 200-300 rpms up
at the top, so I shift when the tach reads 6200 and
the scan tool shows the rpms at 6400-6500 shifts..

An airbag in the Pside rear coil spring does wonders
for traction...

mike

Polecat

maybe more MPH, but ET will be better with sticky tires, 60 ft shows that....................................

But that's also why I was asking for RPM at the big end to see tire/gear combo.

JMatlock88

I dont have a dyno run file, only a printout.

The stall is supposed to be ~3100 and it is a lockup converter custom made by Torco.


I cant account for the blip other than my guess is that it is torque converter locking up? Are dyno pulls inaccurate on the order of 30hp?!

I slap the shifter at 6000 as it reads on the tach and the gear has changed by 6500.

89ROC

That dyno graph just doesn't look right to me. The torque steadily drops off from the get-go. Also looks like it takes the horsepower too long to get up to the max.
I believe the TQ should start out low and build as you get in the upper RPM's. The HP should start out strong and stay there throughout the RPM's.

BadSS

Do you know why the converter wasn’t locked in before 95 mph --- and 95 mph should be less than 5800 rpm for you. You can get a torque spike like that from running two relatively large true dual pipes w/o a balance tube. Maybe it’s a combination of the two? It’s hard to say.

The standard HP and TQ factor used for your dyno graph corrects the weather conditions to 60 degrees, no humidity, and 29.92 in/hg. Depending on the weather conditions when you ran it in, your power could be up or down from 381HP. Weight of the car plays a big role in the performance, to say how far off you are performance wise, you have to consider the weather conditions, the weight of the car, and how good a hook you were getting (none of which I know). Add to that, the “tune” made on the dyno could be different than what it wants at the track that day,,,, and you’ve made a few changes.

Cooling the car down helps more on the heat soaked TPI than with the StealthRam – intake wise. Still every little bit helps and if the clutches in your transmission are marginal and / or the transmission is getting hot / slipping,,, a cool down could do wonders for the times. So, it’s hard to say how much cooling the car between runs would have helped.

Since I’m “here”,,, I believe the conversion from rear wheel to flywheel HP/TQ is done mainly for reference or to estimate what the engine would do on an engine dyno. To get this close to the real numbers, you can’t use the figures generated by the torque multiplication of the torque converter (as you’ve done). Not that you asked for my $.02 on this matter,,, but my best guess, looking at your dyno curve,, you should dyno on the engine stand approximately 460 ft/lbs around 4600 rpm (which appears to be peak torque for the engine,,, not the converter). That’s also assuming a 20% drivetrain loss which is probably a little high for a stock 7.625” rear and 700R4 with a lockup converter.

Skweezn87

Nope.. on LONG tube'd runner intakes.. the TQ will be stronger on the low/mid end and steadily decrease on the high end.

The peak doesnt look bad.. its that big bump in HP and TQ (same spot) that has me bafoozled @ the 5600 rpm area... that just seems very odd to me....

When I had my TPI motor... the more I would hot lap it..the faster it got...

The 95mph lock up seems a little high.. I would try it around 80 mph and see what that does...

But still there is an issue somewhere.. just gotta start digg'n and try to figure out what the problem is........

Rick

89ROC

Maybe you should re-dyno it. That would tell you first hand if you have somehow lost HP.

85MikeTPI

iTrader: (2)

Add to that... Dyno it again at another dyno shop.
This time do an ALDL scan during the dyno runs
and get the dyno run computer file.

mike