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Please Help Find my 2 Tenths!!!!!!!

 
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killacamaro
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Joined: 29 Jun 2003
Posts: 16

104.00 points



PostPosted: Sun Jun 29, 2003 9:34 am    Post subject: Please Help Find my 2 Tenths!!!!!!! Reply with quote

I just came from Dyno session! I got good news and bad news.I have a sbc 434 that made 640hp+570tq. Here's the problem!When I made my 1st pull I only made 585hp+565tq.That equeats to a 10.20 at 130plus.BUT,in my 78camaro weighing 3000pounds with a 1.42 60ft.I only ran a 10.50 at 127mph!I'm missing 2tenths some where and it's not in the motor,it's in the car and I need to find it!!!.I have dynoed many motors and we have never been over a tenth off!The car has stock tank,holley blue pump,a big holley regulator,950BG,glide trans,with a L-88 scoop Crying or Very sad Crying or Very sad fiber glass hood that has a dip around the front part of the cowl.If you have any serious helpful it would gladly be appreciated!! Thanks very much!!!!!!!
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clay
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Joined: 24 Nov 2002
Posts: 3209
Location: South Carolina
318129.23 points


1972 Chevrolet Nova

PostPosted: Sun Jun 29, 2003 1:03 pm    Post subject: Reply with quote

Killer engine man. I might want some advice from you because I'm trying to decide to build a 400 or a 427 SBC. The thing that sticks out at me as maybe being a problem is the fuel system. If you put your 60' time into the calculator your car is pulling about 2 g's somewhere in the 60'. According to David Vizard's tests, this will result in your fuel pressure being reduced 0.3 PSI / ft. / g which would reduce your pressure by 6 PSI using 10' for fuel line length. This means to run 600 HP you would need 12 PSI at the pump and still be able to pump 50 gal/hr using 0.5 lbs / HP / hr. Holley rates the blue pump at 70 GPH at 9 PSI, so at 12, I think you are on the very edge of running out of fuel in the first 100' or so. It is probably on the edge so you can't really feel the car lay down. The Holley black pump is rated at 120 GPH at 9 PSI, but a better choice would probably be a BG 220 or equivalent. Use at least a 1/2" line out of the tank and to the front and I would recommend using a bypass instead of a regulator because they have much better control over the pressure. Good luck. Clay

"If it won't go fast, chrome it!"
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killacamaro
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Joined: 29 Jun 2003
Posts: 16

104.00 points



PostPosted: Sun Jun 29, 2003 1:45 pm    Post subject: Reply with quote

Thanks for the info Clay!I recently purchased a Bg 280 because i was thinking the same thing. I also was thinking about that L-88 hood on my car!When I paid attention to it ,the under side of it isn't open like a true cowl hood! I am trying to figure out the best hood between the snorkel and the cowl!!
quote="clay"]Killer engine man. I might want some advice from you because I'm trying to decide to build a 400 or a 427 SBC. The thing that sticks out at me as maybe being a problem is the fuel system. If you put your 60' time into the calculator your car is pulling about 2 g's somewhere in the 60'. According to David Vizard's tests, this will result in your fuel pressure being reduced 0.3 PSI / ft. / g which would reduce your pressure by 6 PSI using 10' for fuel line length. This means to run 600 HP you would need 12 PSI at the pump and still be able to pump 50 gal/hr using 0.5 lbs / HP / hr. Holley rates the blue pump at 70 GPH at 9 PSI, so at 12, I think you are on the very edge of running out of fuel in the first 100' or so. It is probably on the edge so you can't really feel the car lay down. The Holley black pump is rated at 120 GPH at 9 PSI, but a better choice would probably be a BG 220 or equivalent. Use at least a 1/2" line out of the tank and to the front and I would recommend using a bypass instead of a regulator because they have much better control over the pressure. Good luck. Clay

"If it won't go fast, chrome it!"[/quote]
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clay
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Joined: 24 Nov 2002
Posts: 3209
Location: South Carolina
318129.23 points


1972 Chevrolet Nova

PostPosted: Mon Jun 30, 2003 5:07 pm    Post subject: Reply with quote

I have just ordered a set of AFR 227 heads and an toying with a 427 buildup. I have built a 383 stroker to kind of get my feet wet, but a 4" stroke is kinda tight. Did you use a small journal crank for increased cam clearance? What length rods did you use and what piston manufacturer did you use? Are you using a production block and if so, did you use aftermarket splayed caps and a filled block? If and aftermarket block, is a tall deck version with the cam location raised? I know it can be done, but I'm on a budget like everyone else, so I am looking for the most reasonable way to do it and still be a strong rotating assembly. Mine will be a pump gas street motor (borderline), but will still see race gas and up to a 250 nitrous shot. Thanks in advance for any answers and advice you have. Clay
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killacamaro
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Joined: 29 Jun 2003
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PostPosted: Mon Jun 30, 2003 6:44 pm    Post subject: Reply with quote

I bought a Eagle rotating assembly. (4" crank,6" rod, 13.1 JE dome piston,Bowtie short deck block bored 4.155, filled halfway with concrete,Dart Pro 1 230 cc heads,1050 dom,1 7/8 headers.Motor has 17 dyno pulls and about 30 1/4mile passes,has 275 nos.Oil psi is 70 cold and40 hot.Temp is 170deg.Motor made 640hp/570tq with stock water pump and bent up oil pan on it!Should easily make 665hp!

clay wrote:
I have just ordered a set of AFR 227 heads and an toying with a 427 buildup. I have built a 383 stroker to kind of get my feet wet, but a 4" stroke is kinda tight. Did you use a small journal crank for increased cam clearance? What length rods did you use and what piston manufacturer did you use? Are you using a production block and if so, did you use aftermarket splayed caps and a filled block? If and aftermarket block, is a tall deck version with the cam location raised? I know it can be done, but I'm on a budget like everyone else, so I am looking for the most reasonable way to do it and still be a strong rotating assembly. Mine will be a pump gas street motor (borderline), but will still see race gas and up to a 250 nitrous shot. Thanks in advance for any answers and advice you have. Clay
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bud_less
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Joined: 18 Aug 2003
Posts: 36
Location: vancouver bc
100.00 points



PostPosted: Mon Aug 18, 2003 3:00 am    Post subject: Reply with quote

just loose 200 pounds out of the car somewhere its easy to find you just have to look (under coating????spare tire?inner fenders?
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Paul P
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Joined: 15 Aug 2002
Posts: 2449
Location: Townsend, Mass.
83052.36 points


1971 Chevrolet Chevelle

PostPosted: Tue Aug 19, 2003 8:43 am    Post subject: Reply with quote

I think you are trying to find two tenths at the current weight right??
Check the Front end alignment and tire pressure. A couple of tenths could be there in addition to the before mentioned fuel issues.
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killacamaro
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PostPosted: Tue Aug 19, 2003 10:22 am    Post subject: Reply with quote

Hello Paul. If my car is going straight,how would the alignment pick up some time?Could u be more specific about that and air pressure. Thanks!




Paul P wrote:
I think you are trying to find two tenths at the current weight right??
Check the Front end alignment and tire pressure. A couple of tenths could be there in addition to the before mentioned fuel issues.
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Paul P
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Location: Townsend, Mass.
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1971 Chevrolet Chevelle

PostPosted: Tue Aug 19, 2003 4:09 pm    Post subject: Reply with quote

An Alignment for a staight line only car is quite different than a street alignment.
Street alignments are set with toe in at .125",caster moderate 1-2 degrees,camber postive 0-1 degree.

Drag car in competition will be different, use the following basic guidelines for wheel alignment.


Camber should be set at zero; try to keep the front wheels straight up and down
Toe-in should be zero; toe-in change should be kept to an absolute minimum; be positive that the car does not exhibit any toe-out while the nose is in the air
Caster should be between three degrees and six degrees
Bump steer must be eliminated at all costs

This will decrease the rolling resistance of the vehicle substancially.

See link below

http://www.nhra.com/dragster/1999/issue13/racing_technology.html

Tire pressure should be set to it's maximum to decrease roling resistance as well. I use 40-45 psi in front.
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jeep_406
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Joined: 12 Sep 2002
Posts: 1662
Location: Tewksbury, Mass 01876
53158.50 points


1972 Chevrolet Nova

PostPosted: Tue Aug 19, 2003 11:41 pm    Post subject: Reply with quote

Paul P is so right about rolling resistance.

I wonder if you might be better off with a 3rd gear. I thought the cut off point for a glide was 2800 pounds? Is the car 3000 pounds with you in it?
What kind of short time did you expect?
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techinspector1
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Joined: 09 Jul 2003
Posts: 174
Location: Phoenix, AZ, USA
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PostPosted: Tue Aug 19, 2003 11:54 pm    Post subject: Reply with quote

Clay's remarks about Vizard's tests makes a good argument for a small, front-mounted cell, doesn't it? I'm seeing more and more of these at Firebird. They will pass tech if they are protected from front-end collision.
Richard.

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Richard.

Never try to teach a pig to sing, it wastes your time and annoys the pig.
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killacamaro
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Joined: 29 Jun 2003
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PostPosted: Wed Aug 20, 2003 9:49 am    Post subject: Reply with quote

Hi,Jeep 406. I thought about a 3rd gear but then I see to many racers with similar setups running very fast times and have killa 60's. The 3rd gear probably would help my sixty but would slow me down on the other
end.I always have hade better luck with glides; just way smoother all the way around! Really there is no cut off point with a glide! U see people with 3600pds cars running very fast times and have killer 60 ft times.Look at alot of those easy street guys and all those NMCA guys.U go with what works best for u!My car weighs about 3220 with me in it.I explained at the beginning of the page what I was looking for Jeep 406 so please read it again.Thanks for your help!!





jeep_406 wrote:
Paul P is so right about rolling resistance.

I wonder if you might be better off with a 3rd gear. I thought the cut off point for a glide was 2800 pounds? Is the car 3000 pounds with you in it?
What kind of short time did you expect?
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killacamaro
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Joined: 29 Jun 2003
Posts: 16

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PostPosted: Wed Aug 20, 2003 10:08 am    Post subject: Reply with quote

Hello,Paul. I am not a 100% sure but I think the last time I did my front end I set it up like that,but i wll check again since it has been a while. Also I have seen video of car and it goes pretty down the track. When I'm on the big end I can drive it with 1 finger and go mid 9's ! I haven't tried over 37psi in front tire.What about if your tire says maximal is 35psi should i still try 45psi?I thought to much psi wouldn't let tire use full contact patch like for the rear?I'm not for sure just asking though!Thanks for the info Mr. Paul


Paul P wrote:
An Alignment for a staight line only car is quite different than a street alignment.
Street alignments are set with toe in at .125",caster moderate 1-2 degrees,camber postive 0-1 degree.

Drag car in competition will be different, use the following basic guidelines for wheel alignment.


Camber should be set at zero; try to keep the front wheels straight up and down
Toe-in should be zero; toe-in change should be kept to an absolute minimum; be positive that the car does not exhibit any toe-out while the nose is in the air
Caster should be between three degrees and six degrees
Bump steer must be eliminated at all costs

This will decrease the rolling resistance of the vehicle substancially.

See link below

http://www.nhra.com/dragster/1999/issue13/racing_technology.html

Tire pressure should be set to it's maximum to decrease roling resistance as well. I use 40-45 psi in front.
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