1/4 mile time question

[poboys 94]

Went to the track Friday , first time in 5 years, and it so happenend to be the last test and tune of the season, it was very crowded and only got to make 1 pass in 3 hrs of waiting, anyways I did a disapointing 13.9 @102, but a friend of mine did 13.7 @98, and Im not understanding how I could trap a faster mph but a slower et? I had an expectation of at least 13.5 or better, considering almost all the mods are 4 years old and Ive beat on this car heavily and is my daily driver with close to 200,000 on the factory short block. Fwiw, when I hit 2nd and floored it, it seemed like it hit a flat spot reved but didnt go,I was thinking clutch or valve springs, maybe fuel (still 19lbers) heres the #s in case someone can help break it down:

R/T---.248
60'---2.169
330---6.006
1/8---9.118
MPH---80.13
1000---11.733
1/4----13.951
MPH---101.98

 

[blksn955.o]

do you have the numbers from the friends 13.7 pass? If he cut a 1.9 60ft that could be the reason.

 

[SuperStang83]

Yeah, it could be your clutch, but mainly you need to get some sticky tires and get your 60' times down.

 

[SuperStang83]

You have 13.5s in that mph.

 

[poboys 94]

do you have the numbers from the friends 13.7 pass? If he cut a 1.9 60ft that could be the reason.

Well I saw his slip testerday and I know his 60' was better but not by much was like 2.0 something. He was expecting better#s too with a fresh 306 91 carbed fox body. Why is it I trapped more MPH but got a slower et tho?

 

[poboys 94]

You have 13.5s in that mph.

Actually according to an ET HP calculator at 3400 lbs and 102 it said 12.90, maybe I did the math wrong I sux at math LOL.

 

[Pokageek]

Does the e.t. calc take gears into consieration? I dont think yu can rely on them. Your car is good for a MUCH better time with that MPH.

 

[blksn955.o]

I have seen 102 in sim. weight cars run high 12's or low 13's. It is possible with that mph they also had great 60's IIRC.

What are you reving the motor too? What do you have as far as proof your combo makes power there? You may need to move your shift points down...say your reving to 6k but make peak at 5,200 (even with good heads and a cam that is possible depending on the tune). Your wasting time reving the motor when it would be better off back in the power band...now multiply that by how many times you shift...IF your peaking at 5,200 try shifting at 5,500 or so and see if times go down.

Drop shift points lower and lower until you slow down again to find the sweet spot.

 

[poboys 94]

I have seen 102 in sim. weight cars run high 12's or low 13's. It is possible with that mph they also had great 60's IIRC.

What are you reving the motor too? What do you have as far as proof your combo makes power there? You may need to move your shift points down...say your reving to 6k but make peak at 5,200 (even with good heads and a cam that is possible depending on the tune). Your wasting time reving the motor when it would be better off back in the power band...now multiply that by how many times you shift...IF your peaking at 5,200 try shifting at 5,500 or so and see if times go down.

Drop shift points lower and lower until you slow down again to find the sweet spot.

Shifted around 5500 but need a dyno pull to verify whats really going on, anyplace you can reccomend to take it near our area, Ill go next week. I wish we could have had a few more runs that night. I brought along my timing light and was going to play the fuel pressure too

 

[poboys 94]

http://www.hardcore50.com/members/calculators.htm
heres the calculator site I stand corrected.. at 102 it says 13.28 but thats all it asks is the MPH.

 

[toyman]

I did a disapointing 13.9 @102, but a friend of mine did 13.7 @98, and Im not understanding how I could trap a faster mph but a slower et?

That's easily explained. He was able to accelerate to a higher speed faster than you. That enables him to cover the 1320' in less time even though his trap speed is slightly less than yours. If you were starting at the same time you would see that he's pulling away from you initially and you would start to narrow the gap as you approach the 1/4 mi mark.

 

[Bullitt95]

Went to the track Friday , first time in 5 years, and it so happenend to be the last test and tune of the season, it was very crowded and only got to make 1 pass in 3 hrs of waiting, anyways I did a disapointing 13.9 @102, but a friend of mine did 13.7 @98, and Im not understanding how I could trap a faster mph but a slower et? I had an expectation of at least 13.5 or better, considering almost all the mods are 4 years old and Ive beat on this car heavily and is my daily driver with close to 200,000 on the factory short block. Fwiw, when I hit 2nd and floored it, it seemed like it hit a flat spot reved but didnt go,I was thinking clutch or valve springs, maybe fuel (still 19lbers) heres the #s in case someone can help break it down:

R/T---.248
60'---2.169
330---6.006
1/8---9.118
MPH---80.13
1000---11.733
1/4----13.951
MPH---101.98

I think it's a combination of the following:

1. Engine down on power. By my calculations you have about 250rwhp when the engine should really be putting down close to 300 and you should be getting a low 13's/possibly high 12's ET. You might wanna do a wet and dry compression test on all cylinders to see if you're losing compression past worn piston rings. At 200k miles that wouldn't be surprising.

2. Your 60' time leaves room for improvement. Could be poor traction with too much wheelspin (especially if you gunned the engine too hard), or it could be the opposite and you bogged the engine down off the line instead.

3. With your mods you should be running 24lb injectors so it's possible your engine's leaning out at WOT. If you haven't already upgraded the fuel pump, you might wanna do that too.

 

[poboys 94]

I think it's a combination of the following:

1. Engine down on power. By my calculations you have about 250rwhp when the engine should really be putting down close to 300 and you should be getting a low 13's/possibly high 12's ET. You might wanna do a wet and dry compression test on all cylinders to see if you're losing compression past worn piston rings. At 200k miles that wouldn't be surprising.

2. Your 60' time leaves room for improvement. Could be poor traction with too much wheelspin (especially if you gunned the engine too hard), or it could be the opposite and you bogged the engine down off the line instead.

3. With your mods you should be running 24lb injectors so it's possible your engine's leaning out at WOT. If you haven't already upgraded the fuel pump, you might wanna do that too.

All excellent points, as I expected from this forum. Compression test is being done tommorrow I can see blue smoke on hard acceleration so I have a feeling the rings are letting pressure/oil thru---and the 60' is cause I bogged it to avoid wheelspin + control arms and bushings are toast also--and with the new motor goin in this winter 30lbers are on the list, and thanks for clarifying the mph vs et thing I thinkI would have passed him from half track on, considering I gained 22mph from 1/8 on up thanks for the replys everybody, if I can find a dyno in my area Im going this week and will post up the #s so I can compare this old setup to my new one coming up.

 

[blksn955.o]

Shifted around 5500 but need a dyno pull to verify whats really going on, anyplace you can reccomend to take it near our area, Ill go next week. I wish we could have had a few more runs that night. I brought along my timing light and was going to play the fuel pressure too

There are a few dyno shops in the area,

In the St. Charles area there is MCP with a mustang dyno(off 94 and central school road, were the dyno drags are done). 1st capital 4x4 off Zumbhel(sp?) I want to say a mustang dyno as well. Steig's (Apten 03-04 blower porting guy) off 94 and pralle lane. I know there is a GM guy named Omer that has a shop with a dyno he is an instructor at Ranken and good street cred as a perfectionist. There is an import shop...adrinaline(sp?) that has a dyno. Most offer SCT tuning as well.

In the St. Louis county area there is Mustang Muscle. There is a guy who deals with alot of Viper stuff and goes by the name of PBJ (Power By Joe) on the local site. There are some others but I am not too familure with things outside St. Charles as I am from there and have alot to choose from...

I am not one to really say anyone is better than the other, with any shop you will find someone who is not happy with something. I would call them and see who has the best deal and who you feel more comfortable with. If you want more check out our local site (stlmustangs.com) the owner (one here as well) is an SCT dealer and tweecer dealer that is very helpfull/wise about mustangs and knows alot of shops.

 

[Sirone]

If you would have cut a lower 60' even 1.9 for example the car would have been def 13.5-6 range with that mph you had. What was your friends 60'?

 

[poboys 94]

If you would have cut a lower 60' even 1.9 for example the car would have been def 13.5-6 range with that mph you had. What was your friends 60'?

Im not 100percent sure but I know it was slightly better but still 2. something.

 

[divit250r]

Traction is a huge factor in your ET. My car only put down 265 HP at the rear wheels, but it still gets to low 13s at around 105 MPH. The biggest single difference in your times and mine is that 60' mark. My car may be a few pounds lighter (100 maybe), but that's only roughly .1 ET difference. Did you powershift the car? That makes a big difference, for sure.

Before anybody starts pooh-poohing the powershifting thing, it's just a question. You decide for yourself if it's worth it to take a chance on tearing up your trans. It's worked out well for me, but might not work out well for anyone else.

Scott

 

[final5-0]

Traction is a huge factor in your ET. My car only put down 265 HP at the rear wheels, but it still gets to low 13s at around 105 MPH. The biggest single difference in your times and mine is that 60' mark. My car may be a few pounds lighter (100 maybe), but that's only roughly .1 ET difference. Did you powershift the car? That makes a big difference, for sure.

Before anybody starts pooh-poohing the powershifting thing, it's just a question. You decide for yourself if it's worth it to take a chance on tearing up your trans. It's worked out well for me, but might not work out well for anyone else.

Scott

I Love Your Reply Scott

I would not fault you in any way with your methods

All one has to do is look at your sig with a keen eye
and
Pay close attention to your comments above to see

You've made a strong commitment to find the best et with your Stang

Most will not make that kind of commitment
and
Like you pointed out ... they don't wanna take the chance
or
Beef things up as you did to lessen the chance of breakage

Mini Spool
Yeah ... You could say he is serious about et's

Nice job with so little rwhp Scott

Grady

 

[divit250r]

I Love Your Reply Scott
I would not fault you in any way with your methods
All one has to do is look at your sig with a keen eye
and
Pay close attention to your comments above to see
You've made a strong commitment to find the best et with your Stang
Most will not make that kind of commitment
and
Like you pointed out ... they don't wanna take the chance
or
Beef things up as you did to lessen the chance of breakage
Mini Spool
Yeah ... You could say he is serious about et's
Nice job with so little rwhp Scott
Grady

Thanks, Grady! I do have to say that I didn't mention the spool idea because I actually just cheaped out instead of buying a good limited slip.

So, don't do it like I did and learn the hard way that the people who look at you like you're crazy when you say 'I'm putting a mini-spool in my daily driver' are really the smart ones. Oh, and remember.... :SNSign: helps prevent those mistakes!

Scott

 

[hollywoodstang]

You time should have been high 12's and still running 19lbs injectors are hurting you, all that mods...your car is hungry for more fuel. get 24lbs. that will be perfect for your set up