93 MPH trap speed? What the heck!?!
Thread Starter
Instructor
Joined: Mar 2003
Posts: 229
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From: Knoxville/Wooster TN/OH
93 MPH trap speed? What the heck!?!
So my car finally made it to the track tonight. I came to these conclusions. The car is producing about half the HP it should be, which means either a) there was a gross overestimater of power or something is wrong. I am hoping something is wrong.
I ran a 15.3 @93 MPH... 10.0s 1/8 mile@ 72MPH... 2.38 sec 60ft... :skep:
I have a BB 454 with an Edlebrock Victor Jr. 2R intake Manifold, a Holley 770CFM Carb, a cam probably to radical for the street, long tube heat wrapped headers going into Flowmasters, forged internals, MSD 6A,...
And no the parking can't be engaged because there isn't any parking brake on my car.
With the time that I traped I estimate the the engine is putting out about 206 HP. Is that possible tfor a BB like this to be puttin gout so little HP? My friend who is an experienced driver got the exact same time as I did. So it isn't just my driving skills. :rant:
Any body have any suggestions on this gross failure to perform?
[Modified by dudeskie, 6:52 AM 5/7/2003]
I ran a 15.3 @93 MPH... 10.0s 1/8 mile@ 72MPH... 2.38 sec 60ft... :skep:
I have a BB 454 with an Edlebrock Victor Jr. 2R intake Manifold, a Holley 770CFM Carb, a cam probably to radical for the street, long tube heat wrapped headers going into Flowmasters, forged internals, MSD 6A,...
And no the parking can't be engaged because there isn't any parking brake on my car.
With the time that I traped I estimate the the engine is putting out about 206 HP. Is that possible tfor a BB like this to be puttin gout so little HP? My friend who is an experienced driver got the exact same time as I did. So it isn't just my driving skills. :rant:
Any body have any suggestions on this gross failure to perform?
[Modified by dudeskie, 6:52 AM 5/7/2003]
Team Owner
Joined: Jul 1999
Posts: 26,545
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From: Huntersville NC
Something is wrong...
Even a sluggish bigblock should get you down at 14.8 and 95 - 97 mph... ask me how I know! :) First and easiest thing to look for is make sure your accelerator cable is fully opening up your carb at WOT. Many have had this problem. Car runs fine, but never sees true WOT. After that there are about 1001 other things to check, thought I would start with the easiest. (Oh, and make sure your parking brake is released! :lol: ) MJ
Also, if you have a timeslip with 60 ft, 1000 ft times and speeds it could pinpoint a problem area.
[Modified by MNJack, 11:47 PM 5/6/2003]
Even a sluggish bigblock should get you down at 14.8 and 95 - 97 mph... ask me how I know! :) First and easiest thing to look for is make sure your accelerator cable is fully opening up your carb at WOT. Many have had this problem. Car runs fine, but never sees true WOT. After that there are about 1001 other things to check, thought I would start with the easiest. (Oh, and make sure your parking brake is released! :lol: ) MJ
Also, if you have a timeslip with 60 ft, 1000 ft times and speeds it could pinpoint a problem area.
[Modified by MNJack, 11:47 PM 5/6/2003]
Safety Car
Joined: Oct 2000
Posts: 4,080
Likes: 565
From: Allen TX
Re: (MNJack)
If you don't feel any "flat spots" and the car pulls smoothly, then I would _definitely_ check what MNJack suggests. I was one of the people he's referring to (whether he knew it or not). If the secondaries are not fully opening at WOT, then you're losing 40+% of your power.
I know I was!!!
With the mods you have, I would guess your car should trap ~108mph or so depending upon air density.
Don't be discouraged just yet. You'll get it figured out.
I know I was!!!
With the mods you have, I would guess your car should trap ~108mph or so depending upon air density.
Don't be discouraged just yet. You'll get it figured out.
Thread Starter
Instructor
Joined: Mar 2003
Posts: 229
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From: Knoxville/Wooster TN/OH
Re: (WA 2 FST)
ok so say the throttle cable is fine the way it is and get the WOT fully, what else could be causing such a lack of power? Should I rebuild the entire engine?
Team Owner
Joined: Apr 1999
Posts: 21,953
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Re: 93 MPH trap speed? What the heck!?! (dudeskie)
What's your rear gears? What kind of tranny? What rpm do you launch at? What rpm do you shift at. Radical cams need crutches like big number rear gears and high stall convertors to get moving. I use 4.11 gears and 3500 stall
Even with street tires i can get 2.00 60's with lots of spin
Even with street tires i can get 2.00 60's with lots of spin
Thread Starter
Instructor
Joined: Mar 2003
Posts: 229
Likes: 0
From: Knoxville/Wooster TN/OH
Re: 93 MPH trap speed? What the heck!?! (gkull)
What's your rear gears? What kind of tranny? What rpm do you launch at? What rpm do you shift at.
Tranny=4-speed
Launch RPM=2500RPM ( tried 3000RPM but spun the tires for about 1.5 seconds)
5th Gear
Joined: Apr 2003
Posts: 5
Likes: 0
From: Columbus Ohio
Re: 93 MPH trap speed? What the heck!?! (gkull)
What's your rear gears? What kind of tranny? What rpm do you launch at? What rpm do you shift at. Radical cams need crutches like big number rear gears and high stall convertors to get moving. I use 4.11 gears and 3500 stall
Even with street tires i can get 2.00 60's with lots of spin
Even with street tires i can get 2.00 60's with lots of spin
I'm his roommate and mentor in this endeavor, by the way. Nice to meet you all :cheers:
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From: The Only Corvette in Gila Bend, Az.
St. Jude Donor '09
Re: 93 MPH trap speed? What the heck!?! (dudeskie)
I ran a 15.3 @93 MPH... 10.0s 1/8 mile@ 72MPH... 2.38 sec 60ft... :skep:
Wanna race.... :D See sig.
Melting Slicks
Joined: Dec 2000
Posts: 3,407
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From: Carmichael CA
Re: 93 MPH trap speed? What the heck!?! (dudeskie)
:( it sounds like you should be getting as much power as Bence. Your estimate of the HP is right on, mine dinoed at 203 rwhp and my best time was like 15.25 (see sig). If the engine isn't sputtering or anything like that then it's probably getting fuel OK. I would suspect timing. Make sure you are using the correct vacuum port...easily verified with a timing light to make sure that it's advancing when you pop open the throttle a little bit (don't try to WOT in neutral any longer than one second). Sounds almost like you are dragging an extra 1,000 LBS...oh are you using an anchor chain? Seriously though you should fix your emergency brake.
Team Owner
Joined: Jul 2001
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From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Re: 93 MPH trap speed? What the heck!?! (dudeskie)
timing, carburation or fuel pump... could be possible problems..
What's your timing set to???
What's your timing set to???
5th Gear
Joined: Apr 2003
Posts: 5
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From: Columbus Ohio
Re: 93 MPH trap speed? What the heck!?! (GrandSportC3)
timing, carburation or fuel pump... could be possible problems..
What's your timing set to???
What's your timing set to???
Any more suggestions before we think about tearing the engine apart?
Safety Car
Joined: Aug 2000
Posts: 3,909
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From: Clymer PA
Re: 93 MPH trap speed? What the heck!?! (dudeskie)
I read the title and was thinking WOW....he trapped 93MPH in 1/8 (I trap 91MPH in the 1/8) and then I saw it was in the 1/4. Something is wrong for sure.
First off your 60' times are horrible :) , but a 2.38 60' time would not cause such a bad 1/4 mile time. The worst 60' I ever pulled was in the 2.1X range. That is with a 4 speed manual transmission, 4.11 gears and 215/70/15 TAs.
1) Definitely check for wide open throttle. Is that 770cfm carburetor vacuum or mechanical secondaries? If they are vacuum check to make sure they are opening. If they are mechanical secondaries get someone in the car and have them kick the gas pedal to the floor. You need to look down the carburetor to varify that the throttle blades are opened completely. This is easiest done with the car off :) .
2) You need to varify your timing. Hook a timing light up and check your total timing advance. It should be around 36-39 degrees total.
3) Check for vacuum leaks. Vacuum leaks can reak havok on a motor.
What kind of heads do you have? Do you know what is done to the heads?
P.S. You could benefit from a larger carburetor....770 is too small in my opinion.
[Modified by bence13_33, 1:17 PM 5/7/2003]
First off your 60' times are horrible :) , but a 2.38 60' time would not cause such a bad 1/4 mile time. The worst 60' I ever pulled was in the 2.1X range. That is with a 4 speed manual transmission, 4.11 gears and 215/70/15 TAs.
1) Definitely check for wide open throttle. Is that 770cfm carburetor vacuum or mechanical secondaries? If they are vacuum check to make sure they are opening. If they are mechanical secondaries get someone in the car and have them kick the gas pedal to the floor. You need to look down the carburetor to varify that the throttle blades are opened completely. This is easiest done with the car off :) .
2) You need to varify your timing. Hook a timing light up and check your total timing advance. It should be around 36-39 degrees total.
3) Check for vacuum leaks. Vacuum leaks can reak havok on a motor.
What kind of heads do you have? Do you know what is done to the heads?
P.S. You could benefit from a larger carburetor....770 is too small in my opinion.
[Modified by bence13_33, 1:17 PM 5/7/2003]
Race Director
Joined: Jan 2003
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From: State of Confusion
Re: 93 MPH trap speed? What the heck!?! (dudeskie)
... a Holley 770CFM Carb, a cam probably to radical for the street...
Race Director
Joined: Sep 1999
Posts: 11,361
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From: Plano TX
Re: 93 MPH trap speed? What the heck!?! (Glensgages)
Make sure the timing advances as the rpms go up. I once had a camaro that was a dog. Found out the weights in the distributor had rusted to the shafts and the advance would not increase at all. Engine ran smooth, didn't backfire. Just a dog. Fixed the advance and it felt like it gained 100 hp.
To check you have to unplug the vacuum advance. Then rev the engine to 3500 rpm and check that you are getting 36 degrees advance.
To check you have to unplug the vacuum advance. Then rev the engine to 3500 rpm and check that you are getting 36 degrees advance.
Team Owner
Joined: Jul 2001
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From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Re: 93 MPH trap speed? What the heck!?! (Archidictus)
timing, carburation or fuel pump... could be possible problems..
What's your timing set to???
Timing is advanced between 12 and 16 degrees, carburator is about 2 months old along with the brand new FPR. Both work very well. The fuel pump is an out-of-tank T-Rex or something of the sort that pumps in at 16psi unregulated. The fuel system is working fine and the timing was checked last weekend.
Any more suggestions before we think about tearing the engine apart?
What's your timing set to???
Timing is advanced between 12 and 16 degrees, carburator is about 2 months old along with the brand new FPR. Both work very well. The fuel pump is an out-of-tank T-Rex or something of the sort that pumps in at 16psi unregulated. The fuel system is working fine and the timing was checked last weekend.
Any more suggestions before we think about tearing the engine apart?
What about your heads?? They might be holding you back too...
Race Director
Joined: Oct 2000
Posts: 15,120
Likes: 79
From: central FL, near the beach.
Re: 93 MPH trap speed? What the heck!?!
lots of good advice ahead of me. thanks guys!
i would pull the spark plugs and they better be light tan.
[Modified by Matt Gruber, 3:43 PM 5/7/2003]
i would pull the spark plugs and they better be light tan.
[Modified by Matt Gruber, 3:43 PM 5/7/2003]