New track times after dyno

zenboy99 · Oct 13, 2003

Last week I dynoed 255rwhp with the car cold and running lean, once the car was warm and I got the AF ratio down I made 246rwhp and ~300rwtq. Bought some drag radials and went to the track on Saturday.

Previous best:
14.25 @ 97.6 mph 2.15 60 foot

New best time with drag radials:
14.15 @ 96.7 mph 2.05 60 foot.

Don't these times seem a little slow for the horsepower I'm making? Most of you guys with the same mods are running 13's and trapping at almost 100mph. I tried different shift points 5300-5600.

I couldn't do any better then a 2.05 60 foot with the drag radials, I'm not sure how to launch on those things. I did a 5-10 second burnout and got them nice and warm. I launched at 3000 rpm and the car bogged, then at 3500 and the car spun. Any ideas?

Killercanary · Oct 13, 2003

If it bogged at 3000 and spun at 3500, you need to keep the launch rpm at 3500 but slip your clutch. DR's will take a little while to get used to. They are a great tire, but they are not like a slick where they'll take a hgih rpm dump. If you leanr to slip it, you could probably go to 4000 or so.

What was the air like that day, meaning barometric pressure, temp, and humidity? What's the track elevation? If your tach is correct, I'd shift it at 5500. What rpm did the peak HP and TQ occur? I do agree that it does seem a little low, but I think you'll get it with more practice.

zenboy99 · Oct 13, 2003

temps were in the mid 70's with really dry air. The track is in the flatlands of Illinois so maybe around 400 feet altitude. I'm thinking that if my car made that much power my tach must be off, maybe its time to get a shift light. Peak horsepower was at 5000 and torque was at 3700.

Forgot to mention that I replaced the hall effect sensor in the distributor after the dyno runs. I checked the timing after that and at the track, but it was right at 14 degrees.

StangJonGT · Oct 13, 2003

I wouldn't be burning out for 5-10 seconds on a drag radial. From what I've learned, there is no need for the smoke show on a radial; just a quick spin to clean them off. If you have slicks, however, burn the $hit out of them before each run.

Jon

Killercanary · Oct 13, 2003

StangJonGT- The drag radial is a totally different rubber type than a typical radial tire. You are correct in that a regular radial doesn't need a big smokey burnout. I'm not sure which DR's he's running, but the nittos seem to need more of a burnout than the BFG's. The rubber in the nitto is a dual compound design. This means that the rubber is hard when the tire is cool during normal street driving, but becomes sticky when hot thus providing great traction at the strip.

zenboy99 · Oct 13, 2003

Yep, they're Nitto's, 275x40. The Nitto rep at the world Ford challenge told me I would need to do a nice smokey burnout to get them to hook.

StangJonGT · Oct 13, 2003

Killercanary said:
StangJonGT- The drag radial is a totally different rubber type than a typical radial tire. You are correct in that a regular radial doesn't need a big smokey burnout. I'm not sure which DR's he's running, but the nittos seem to need more of a burnout than the BFG's. The rubber in the nitto is a dual compound design. This means that the rubber is hard when the tire is cool during normal street driving, but becomes sticky when hot thus providing great traction at the strip.

I thought rubber as a compound behaved with dual personalities, as described by you. I didn't know you needed a special dual compound to react this way to heat. Either way, I admit that I have only heard a few things on this topic, but have heard it many times repeated. You seem to know your stuff though, according to your brilliant times--so I'll chalk this up to inexperience and thank you for the information.

Jon

GTJake · Oct 13, 2003

That trap speed seems really low for your mods. I bet you were shifting too low or too high. My guess is too low. I'm no drag racing expert, but with my combo I got my best times by shifting 1-2 at 5800 and 2-3 at like 5600.

Try plugging your dyno chart into Zero Signal's Shift Point Calculator. That should help find your exact shift points.

Possibly your tach is off too. But you should have been able to check that on the dyno.

Good Luck.

Jake

Killercanary · Oct 13, 2003

Well, it sort of does, but these tires are made to enhance it. BFG really doesn't recommend a big burnout with their DR's as they claim that the rubber will come off and form for alck of a better term "rubber ball bearings" and will actually hurt traction, but then again the BFG's rubber is much softer at ambient temps than the nittos are, so they require less heat to become as sticky. This is the main reason why the BFG's life span is on average less than the nitto's, and its usually by a lot too. The ET streets I run require virtually no burnout. I just smoke them enough to clean them and put a little heat into them.

FastmanGT · Oct 13, 2003

GTJake said:
That trap speed seems really low for your mods. I bet you were shifting too low or too high. My guess is too low. I'm no drag racing expert, but with my combo I got my best times by shifting 1-2 at 5800 and 2-3 at like 5600.

Try plugging your dyno chart into Zero Signal's Shift Point Calculator. That should help find your exact shift points.

Possibly your tach is off too. But you should have been able to check that on the dyno.

Good Luck.

Jake

My $0.02 is hes shifting waaaay too high, especially with a stock cam. He said max HP occurred ~5000, and hes shifting anywhere between 5300-5600. Shift around 5150-5200RPM and I'd wager at least a .1 sec drop in your ET.

GTJake · Oct 13, 2003

Like I said I'm no expert, but I have similar mods to him except for the MAF, TB and the 24#'s and I shift my car where I said and I got an 8.9@81 which is equal to an 13.88@102 on the quarter mile calculators.

With the extra breathing mods I think he's shifting too low, but that's just my opinion. Unless the 24#'s are hurting him that much, but he said he got the air/fuel ratio straightened out.

Jake

GTJake · Oct 13, 2003

OFF TOPIC: Zenboy99, did you go to Rock Falls in Eau Clarie, WI? How was the prep and stuff? How many runs do you usually get in there? I'll have to meet up with you next summer and run.

Jake

Killercanary · Oct 13, 2003

I agree with Jake. 5200-5300 is about right for a stock head, stock cam, stock intake car where peak power occurs normally around 4800, but on one with an intake like he has, 5500 is a better shift point. I shifted mine at 5500 with a similar combo and it yielded the best results... a 13.83 at 98.55mph in my vert.

Stock I shifted at 5000rpms, with exhaust and pulleys I shifted at 5250, then at 5500 with the intake, and now 6000-6100 with the heads and cam... and these points were determined by trying various shifts points to find what made for the best times.

zenboy99 · Oct 13, 2003

Thanks for all the reply's, any info is good info.

The tech guy at the dyno told me that when my speedometer read 6000 rpm the engine was at 5700, maybe he screwed up. I think I'm going to buy a shift light, they're only $39 from summit. My tach was acting a little funny, didn't seem like it was revving very smooth so maybe thats the problem.

I'm also wondering if something happened when I replaced the hall effect sensor, but the timing was right so I'm not sure.

GTJake, I haven't been to Rock Falls yet, although I drove by there the last two weekends, I saw about 15 Mustangs between Eau Clare and the Twin cities.

Does anyone have the link to Zero Signals shift point calculator?

GTJake · Oct 13, 2003

Here's his web page. It's at the very bottom.

http://www.u.arizona.edu/~jtennant/Doc1.htm

Where do you usually race at?

Jake

zenboy99 · Oct 13, 2003

I usually race at Byron dragway in Illinois, Cordova Illinois, or Great Lakes Dragway near Milwaukee. Great Lakes is a horrible track, horrible track prep and the timing system has broken down the 3 times I've been there. In November I plan on going to Joilet Illinois near Chicago, thats the most beautiful track I've ever seen. Rock Falls is about 2.5-3 hours away, but I'll meet you there in the summer sometime.

GTJake · Oct 13, 2003

That would be cool. Yeah, Rock Falls is about 2-2.5 hours away from me, but it's the closest 1/4 mile track around. Minnesota Dragways is looking to build one near the Twin Cities though, so that would be cool.

As far as the track times. I say try that shift point caluclator and hit up the track again.

Good Luck

Jake

WhiteDevil · Oct 13, 2003

Yeah i agree with GTJake, have my shift light set to 5,800 and i have stock heads and cam, its seems to yeild pretty Respectable times. i would expect more MPH from you Zero cause it seems u got more HP and TQ.

WhiteDevil · Oct 13, 2003

oops here is my sig

zenboy99 · Oct 14, 2003

Here is what the shift point calculator told me;

Gear rpm mph
1st to 2nd 6000 36.8
2nd to 3rd 5900 60.2
3rd to 4th 5600 86.9
4th to 5th 5800 119.0

I'd like to talk to the guy and see how he set this thing up, looks like a ton of math! I hope he got credit in school for that.

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