Can You Racers Help Me Diagnose My Disappointing Track Results? - Ford Mustang Forum
 
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post #1 of 14 (permalink) Old 09-09-2014 Thread Starter
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Angry Can You Racers Help Me Diagnose My Disappointing Track Results?

Hello everyone, thanks for taking a peak. I just registered because I am at a loss with whats going on with my car (or not going on I should say).

First the car - it's a Mustang...wrapped in a 1967 mercury Comet skin Here is the basic setup:

1967 Mercury Comet 202, 3350 lbs with driver

CHP 331 street fighter short block, balanced, cast crank, forged flattop pistons (-4cc), makes 10.35:1 compression; Edelbrock Rollin' Thunder bump stick (hyd roller - degreed), AFR 165 heads, Performer RPM intake, Edelbrock Thunder 650 carb, Hooker headers (1 3/4), dual exhaust dumping through two glass packs, Accel electronic breaker less distributor. Rearend is a 9' posi-track with 4.11 gears and I have the full Calvert racing setup - cal-tracks, split mono-leafs and 9-way adjustable shocks. Tires are 27" tall Mickey ET streets

I'm seeing a lot of similar setups, in Mustangs, running low 12's and some into the high 11's with N/A carb combos like this. I clearly have a bottleneck or something wrong here. I'm wondering if it's valve float but I have no experience with it, so I am soliciting input from you smart folks.

Here is a sample run -
ET 13.10 @ 108
60' 2.0 (this is a driver issue...very easy to blow the tires off this car - this is with full air in the tires and launching off idle, stepping into it)
1/8: 8.58

Here is where it gets kinda weird - i finish the quarter at 110.8, but I have a system in the car, computer, that says i reach 110 mph in 12.75 seconds and I hit a top speed of 111.8.

So it seems the car is going flat well before the end of the quarter.

Am I wrong...? With this setup shouldn't this car be capable of running solid 12's? Could valve float be the issue and explain the flatness on the big end?

The car is hella snappy off the line, doesn't have a hesitation or bog anywhere in the rpm range.

What should I be looking at here? Thank you in advance for your input!

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post #2 of 14 (permalink) Old 09-10-2014 Thread Starter
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post #3 of 14 (permalink) Old 09-11-2014 Thread Starter
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Well with 229 views and no suggestions or feedback I guess this isnt the right place for discussion. Moving along. Thanks I guess
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post #4 of 14 (permalink) Old 09-11-2014
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The problem to me seems to be 3350 lb car and a 2 second 60 ft. Also you may need to jet the carb a little bigger, you may not be putting enough gas in it on the top end. When you lose MPH go bigger on the jets. you will also lose MPH on the top end with jets that are too big. So you will need to make some test and tune passes. The weather will also make a difference in your et and mph. I don't know anything about a Edelbrock carb, jet changes are easy with a Holley type carb. You can change all 4 jets in 5 minutes. I run a 650 Quick Fuel on mine. I hope this helps
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post #5 of 14 (permalink) Old 09-12-2014
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You did not mention what kind of fuel system your running. Are you getting enough fuel for the demand?

27" tires with a 4.10 That's border of being too big of a gear and your probably pushing really high in RPM's at the trap.

What kind on transmission are you running? Stick or auto, if auto what kind of converter (specs) do you have?

How much air pressure are you running in the tires?

Are you sure you have your timing correct?

93' LX hatch, 460 w/150 plate, TH400, 9" w/ 3.60 spool. Best (so far!) of [email protected] 146 mph with 1.40 spinning 60' on steel heads
Reese,
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post #6 of 14 (permalink) Old 09-13-2014
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I potential see many issues...full air in tires and most likely not enough carb. Smoking et streets shouldn't be happening. Guys run single digits with those. Also maybe you are running out of gear...what rpm thru traps? Stick or auto? Throw in a holly, drop tire pressure and launch on the gas and brake(if auto). If stick there's usually a lot of driver error that results in slower times. I ran those times on a 17" regular street tire so something is definitely not right.

"Mustangs only win, when they race each other"...my dad(he's a Chevy guy)...hahaha.
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post #7 of 14 (permalink) Old 09-16-2014 Thread Starter
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hi guys. sorry, been away. thanks for the feedback & input.

I have a T-5 trans (5-sp), hardened, in the car, all the usual upgrades, and a MGW short throw shifter. The rear tires are actually 26.5", 255/60R15's.

I know the 60' is horrid, which is surprising, given the fact I have full Cal-tracs, split mono leaf's and 9-way adjustable shocks, but I also know I have a lot of dialing-in to do there. I have done some adjustments and so far, without radical changes I'm dancing all over that 2-second mark. With street tires it was much worse, so there has been some improvement.

I launch the car from idle and try to step into it - if I don't it's sit and spin and the 60' will be 2.20 plus.

I did not lower the tire pressure below 26 lbs because I have not yet got the sub-frame connectors in. I have them, pre-fabbed sitting in the garage, just recovering from (another) back operation and can't do much under the car w/o the wife ripping on me. Hope to get them in soon so I can make another go at the track before the season ends.

I also have a rear stabilizer bar to put on the car to hopefully help tie it all together. I am of the opinion that with the horrid 60' and chassis flex I am losing maybe .6-.8 of a second - sound fair? With that assumption it's fair to call this a mid-12 car - does that sound right given the parts n pieces put into it?

I was just shocked initially, it feels a lot faster and I though it would do better, but I suspect the chassis is costing me a lot at this point, driver mod needs work (though I power shift well) and the Cal_tracs aren't giving me enough of a hit on those rear tires.

Timing is ~11deg initial, 34 total and is all in at 3500. Running a .35 plug gap with the plugs recommended by AFR for the heads.

Carb is a 650 thunder, per edelbrock's recommendations, running 6 psi fuel pressure and the fuel pump is a electric Jegs unit, #15913, 95 gph free flow. Running a Holly fuel pressure regulator. There isn't a hesitation in the car at all. You can floor it from idle and it opens right up. I do have a 750 on the shelf which I ran briefly - the car loved it but the wallet didnt. Didn't have any issues with bogging/hesitation with it but the driver has a heavy foot The 650 was on the car for the track day.

Correction - the rear gear IS a 4.11. Quick performance 9" trac-loc posi unit. Yea, there is very little first gear I'm not sure what the rpms are when I trap, around 56-5700. I trap well into 4th gear, probably hitting 4th right around the 1000' mark.

I have not been able to get to a chassis dyno yet. It's 90 miles one-way and dude seems to be busy when I'm not so far. That is a priority as I'm basically guessing on my carb setup and best shift point.

Again, thanks for your input guys. I really am just a shade tree, this is the most I have put into a build. While I read a lot I learn the most by listening to others that have the knowledge and experience - I appreciate it!

Last edited by 67Merk; 09-16-2014 at 12:50 PM. Reason: added shifter info
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post #8 of 14 (permalink) Old 09-16-2014
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That gear is too much for 26's. The car is falling on it's face on big end. The RPM's are probably higher than than that.

Of course this is just my thought. There is a fail on big end. Not enough carb/ fuel and big gear for those tires.

Dyno would tell you more..

93' LX hatch, 460 w/150 plate, TH400, 9" w/ 3.60 spool. Best (so far!) of [email protected] 146 mph with 1.40 spinning 60' on steel heads
Reese,
Been saying single digit coming for 3 years.....guess I finally made it!
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post #9 of 14 (permalink) Old 09-16-2014
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Wow, a 1967 Mercury Comet 202 in Missouri..?!?!?! You don't see many of those around, let alone MO. My dad has a 1967 Coment 202 (a lot of goodies..too many mention...completely restored...but it's Amazon Green and is present at most major car shows here in STL). What part of Missouri do you live? What track do you go to? What dyno/shop did you contact? I highly recommend Mustang Muscle here in St.L. It's off of Highway 30...excellent shop, great tuner...give them a call.

That 60ft time is the main reason why you aren't in the 12s...4.11s do seem steep and probably why you can hook up (and not launch at a higher RPM). I would think a 3.73 (or get a taller tire) would be a better fit with the T5 (it has a very short 1st gear).

You defintely need to get it on the dyno to make sure you aren't running out of fuel up top and to make sure your timing curve is appropriate for your engine. Do you have a fuel pressure guage at the moment? If not, may be time to purchase one....

Why not put the 750 back on? It would breath a lot better on the top end? I would take both carbs to the dyno (when/if you go) and run them both to see how each compare. I bet you stay with the 750.

Matthew 26:52-54 / Go Pack Go!

1987 Mustang GT Hatchback - 2V Mod Swap In The Works

1997 Lincoln Town Car, PI Intake/Cams, Sofa-On-Wheels, "Fat Tony" we call it

2001 GT Convertible - D1SC / Geared / Cammed / 440wh 400wt - TOTALED 2/2019
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Your 4.10 gear is not to much gear for a 1/4 mile car. If your 1 st gear is to short, maybe you need to look at going with a different trans. In order to get a good 60 ft time you are going to have to leave the line hard, leaving off idle will not produce a good 60 ft time. Soften up the suspension quite a bit, get some slicks and put in 10 to 14 psi. I don't think you are losing .6 to .8 on the 60 ft. maybe .3 to.5.. 9 second door cars have a 1.20 to 1.30 60 ft I think you are looking at 1.50 to 1.75 60 ft. Making big HP is useless unless you can hook it up. I would not worry about my motor and how much power it is suppose to make right now, I would work on the suspension and how to leave hard. A good 60 ft. is very important in a good 1/4 mi. ET. my opinion
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post #11 of 14 (permalink) Old 09-17-2014 Thread Starter
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Quote:
Originally Posted by JonR2006 View Post
Wow, a 1967 Mercury Comet 202 in Missouri..?!?!?! You don't see many of those around, let alone MO. My dad has a 1967 Coment 202 (a lot of goodies..too many mention...completely restored...but it's Amazon Green and is present at most major car shows here in STL). What part of Missouri do you live? What track do you go to? What dyno/shop did you contact? I highly recommend Mustang Muscle here in St.L. It's off of Highway 30...excellent shop, great tuner...give them a call.

That 60ft time is the main reason why you aren't in the 12s...4.11s do seem steep and probably why you can hook up (and not launch at a higher RPM). I would think a 3.73 (or get a taller tire) would be a better fit with the T5 (it has a very short 1st gear).

You defintely need to get it on the dyno to make sure you aren't running out of fuel up top and to make sure your timing curve is appropriate for your engine. Do you have a fuel pressure guage at the moment? If not, may be time to purchase one....

Why not put the 750 back on? It would breath a lot better on the top end? I would take both carbs to the dyno (when/if you go) and run them both to see how each compare. I bet you stay with the 750.
John I may have met your dad. I had a guy follow me in town here one day (Saint Robert) so i pulled over and he told me he had one and he was out of Saint Louis - in fact he texted me some pictures I think he said he had a meeting (or business) on Ft. Leonard Wood. You might ask him if he remembers seeings a red/black one here.

Thanks for the dyno recommendation, I'll check them out. I have been trying to use Sho Me Speed in Springfield but scheduling has been a problem.

As far as a FP gauge, just a inline, under the hood which I have used at idle and under load with the car on stands.

I do have a set of new 3.55 gears on the shelf. Have been debating trying them. I'd like to get a full track day to make sure I have the Cal-trac's dialed in. If I can't hit a 175 or better 60' then I'll probably swap gears :/ I do love the 4.11's for 'round town

Closest track for me is in Rodgersville, Ozark Raceway. It's about 80 miles from me. Only went that one time for my baselines. Trying to make some significant changes before I go back. Don't want that same disappointment

On timing, I went with the recommendations that came with the cam instructions

SO DYNO - critical and will do ASAP. Fuel supply, jetting/rods, powerband, timing

750 cfm - good call, will take it with, comapre

Gears - question mark, subject to cal-trac adjustment 3.55's on the shelf. I know a lot of folks champion 3.73's. Was going to go with them and figured I might get them and end up wishing I had went lower. So I decided to start numerically higher and if I didn't like them I figured I'd have a good idea where I wanted to be. The 3.55's are NiB craigslist specials from a guy that went with a diff gear.

Chassis: SUB-frame connectors and rear stabilizer bar - sitting in the garage waiting for spousal/dr's release. Once they are in not sure how much more I can do to the caissis, other than work/work/work until I am sure it's dialed in right. I have Cal-Trac traction bars, split mono leafs and 9-way adjustable shocks on the back with lakewood drag shocks up front. No sure how to go about checking for binding alone in the garage - any ideas?

Tires - Slicks - will do. I have avoided buying any until I get the sub frame connectors on the car If I had them I would probably have to test them. Be my luck I'd pop the back glass out or something Originally I had BFG's on the car - it was like driving on ice. The Mickey T ET's made a BIG difference, but clearly more improvement to be had.
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Yeah, I think you did meet my dad. My brother used to live in Saint Robert and they told me they met a guy who had a '67 Red/black Comet down there (and now that i think of it, they mentioned your 4.11 gears...seriously...). Small world, man. I tell my dad I found you on here; he will be pretty excited about it. Would be cool for you all get togethe and get some pics of both your cars.

MT Et Streets are excellent tires, My uncle has a vortech-charged '02 Z28 pushing 500+ to the wheels and he uses them with a trans brake and a Turbo 400, he has no problems with traction (he is dipping into the high 10s). I highly doudt it's the tires. Do you have Traction bars on your rear leaf springs? May be something to look into. The SFC are a must...

If you can get up to STL and check Mustang Muscle out they are very good. The owner is my cousins step-dad so basically family and they do good work.

Before changing out rear gears, get the chassis/suspension in line. My dad runs the MT ET streets as well with 3.70s, subframes, no traction bars (he is pushing 420+ to the wheels) and he has no issues with traction either. I really think if you dial in the suspension/chassis yours 60fts will drop significantly.

Very cool to see you on here. I'll let my pops know I ran into you on here. PM me if you want.

Matthew 26:52-54 / Go Pack Go!

1987 Mustang GT Hatchback - 2V Mod Swap In The Works

1997 Lincoln Town Car, PI Intake/Cams, Sofa-On-Wheels, "Fat Tony" we call it

2001 GT Convertible - D1SC / Geared / Cammed / 440wh 400wt - TOTALED 2/2019
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post #13 of 14 (permalink) Old 09-20-2014 Thread Starter
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Quote:
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Yeah, I think you did meet my dad. My brother used to live in Saint Robert and they told me they met a guy who had a '67 Red/black Comet down there (and now that i think of it, they mentioned your 4.11 gears...seriously...). Small world, man. I tell my dad I found you on here; he will be pretty excited about it. Would be cool for you all get togethe and get some pics of both your cars.

MT Et Streets are excellent tires, My uncle has a vortech-charged '02 Z28 pushing 500+ to the wheels and he uses them with a trans brake and a Turbo 400, he has no problems with traction (he is dipping into the high 10s). I highly doudt it's the tires. Do you have Traction bars on your rear leaf springs? May be something to look into. The SFC are a must...

If you can get up to STL and check Mustang Muscle out they are very good. The owner is my cousins step-dad so basically family and they do good work.

Before changing out rear gears, get the chassis/suspension in line. My dad runs the MT ET streets as well with 3.70s, subframes, no traction bars (he is pushing 420+ to the wheels) and he has no issues with traction either. I really think if you dial in the suspension/chassis yours 60fts will drop significantly.

Very cool to see you on here. I'll let my pops know I ran into you on here. PM me if you want.
Yea, as I recall your brother was a asst. mgr at Wal-Mart or something like that . Your dad sent me some pics of his car, beautiful, and so far he's the only other guy I have met with a 202. My car wouldn't hold a candle to his - very nicely done - pls say 'hi' to him for me.

I may well take your suggestion with respect to Mustang Muscle. I'd have to drive the car up there so I'll have to time it for decent weather, subject to their availability.

The cal-tracs are a top of the line system, common in 8-10 second cars and used by a lot of the national bracket champs running leaf spring cars. I have complete confidence in them, just not in my ability to get them dialed in yet . They allow you to pre-load the leafs and control the amount of hit on the rear tires. I know I have a lot of work to do here.

As this car is N/A I was hoping to get it into the low 12's, which should be very doable with a built/balanced 331, but I have a full second to drop to make that happen. I know it's in the car, just got to get the thing dialed in right . Having read through here, I'm less incline to think it's the build and more inclined to think it's the lack of informed tuning - A/F, precise timing, chassis.

I'll shoot you a p m about possibly getting up that way. Small world indeed!
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108-110 should yield high 11's if the launch is tight. I didnt read the whole thread, but drop the psi in the M/Ts to 20 psi or less, see if you can bring down those 60 ft. times.

Im running 12.7's @ 103-104 with a T-5 and 3.73 gears with much less power, so looks like you gotta get that beast off the line better

The 3300+ lbs could be hurting you a little...?

The question is not when's he gon' stop, but who is gonna stop him? ~ Super Soul
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