Check out my time slip…help me get faster!
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Sooo here the combo……
70 4 bolt main block, 461 , compression 10.2, 340 Cfm eheads,, port matched northwind intake, camshaft: 248 intake 254 exhaust 620 gross lift 112 lobe separation. Vacuum pump I am also running a Holley terminator x with a 1300 cfm throttle body…80lb injectors Timing is set at 32-33 degrees at WOT MT e-street R lowered to 14psi Last night at the track ran…..11.68 at 117mph with a 1.77 60ft Was looking for some tips to get faster with my combo….I probably need a cam swap is what im thinking? Thanks boys! |
60ft looks soft for your speed and ET.Converter suspension?Tom
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Looks like you've got the dropped base air cleaner from Butler. Try making a run without the air cleaner on it and see what happens. One of my customer's did that based on my suggestion and his car picked up 1.5 tenths. I believe the air cleaner element comes too close to the middle restricting flow. What rear gears? Transmission & converter? Cal tracks?
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I'd also say the MPH's are higher than the ET's, suggestion possibly you're not hooking good. (this would make the 60' slower and ET's)
As others said more combo info may help. But I would try a set of slicks if allowed to run them. If not, what is your launch RPM or how you launch it? Engine seems to be making good power just not getting it all to the ground I think. :confused: |
Weight? Rear gears?
Th cam and intake and maybe even the 340 cfm heads killing the bottom end? My 78 TA with my 0.030 over 2 bolt 455 320 CFM E heads and a 239/247 HFT Torker II and an 850 when it weighs 3750 with light wheels in good air can run high 10s @124. 1.6 60 ft. Toss rear DOTs and heavier snowflakes on all 4 corners runs 11.50s at about 119 even with the air cleaner on it . But that was with 4.11s and a Continetal convertor about 3500 stall. I will say with my previous SR cam motor when we pulled the air cleaner element out after tuning for the air cleaner it freaking lean popped out the open Shaker that night! So it can make a difference. Even a 14x4" air cleaner on the 500" IA Camaro killed it 0.3 seconds! |
Im not sure the exact weight its mostly a stock setup with full stock interior and those 17inch snowflakes….whats a good way to lighten her up?
The rear gear is 3:42…. Im definitley not getting all the power to the ground….I’m launching off idle because if I power brake to even 2k it spins like crazy so i definitely need some suggestions to fix that….I’ll definitely work on the slicks setup Long tube headers and 2.5 inch exhaust also if that can be improved? Also wondering how much power I could pick with a good dyno tuning session I will definitely try taking the shaker off also |
Your 60 ft times suck!
There’s a lot left on the table there. Your cam pick duration wise is not a good match to your 340 cfm CNC heads and that compression needs to go up to 11 to 1. |
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Engine combination should have you in the 120's for mph..exhaust is too small need 3 inch, is your convertor slipping? Is the total timing optimized? Lots left in the combo..a few things are just chocking the power, as mentioned the shaker/air filter setup can choke. What is your rear suspension?
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First off, beautiful car. Just my opinion here but I see the car running in the 11 20s at the moment. If you can get the 60 ft to a 1.60 it should do that. Assuming you have 4,25 stroke crank and the car weighs around 3800, I would suggest a rear gear of 3.73 or 3.90 to get your start line ratio more on par. Also I think you stated that with any heavy stall at the line you are blowing the radials up on launch. Change to slicks or you ll need to build some heavy anti squat into the suspension to crush the radials. Then to squeeze everything from the motor try the things the guys have suggested (timing,read the plugs, air cleaner delete), maybe even drop the exhaust and try collector extensions with different lengths. It works. With that and the right conditions you can hit your goal, I know how it is, a couple passes and we always want more, lol. Good luck man, peace.
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Get somebody to video your launch or do what I did and put a Gopro with suction cup behind a rear wheel to see if you're spinning or not. Mine launched soft and didn't spin so I swapped converters for a huge difference. X2 on get a 3" exhaust which should pick up a few tenths and bring mph up. Maybe bump timing up, too. My D ports liked 37°. I think a chassis dyno would really get you on track. Very nice car and build, should go easy hi 10s when sorted out.
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Im not to sure if the converter is slipping because I am having to leave off idle…I definitely need to learn more about how to address that too The total timing isn’t optimized yet either…I just put about 33 degrees total timing in it but the plan is to get it dyno tuned which I believe will help a lot…. The rear suspension is pro touring F Body drop springs and sway bar….viking adjustable shocks and anti squat brackets along with of course solid body bushings and subframe connectors Thank you guys for all your help….I’m learning a lot even if some of my times suck haha |
I really think the small 2.5 exhaust is killing a lot of power…..cut outs might make a big difference?
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The exhaust is hurting.
Pick up a 17" snowflake and pick up a 15x8" Prostar wheel! Slicks are lighter than even DOT sticky radials. Betting the convertor is too tight, but then you get in the "too loose for street". I have a 3000 10" that when I had 3.42 and cruising it would start to flash up with load going over an overpass on the freeway! The Continental does not do that but does flash-mine is just a click tight for my cam. I agree the cam is good for the heads/intake I just think all are a little big for 3.42s and a tight convertor. My E Head motors use way more timing but are the older chambers 38 and 40. Sounds like the car is set up for handling-so you also have to look at what aspect you are shooting for cornering/autocross or drag. My forst 455 the car was set up for autocross and even with drag DOTs on the rear it only ran 12.20s @117! You could have a set of lighter drag wheels/tires to swap on. Bump the timing to 36-38-something you can do at the track. Next step you could try footbraking up the rpm, or a different convertor. FWIW I had a third convertor I am about to try on my IA/Camaro as my 60 fts on it are soft also. |
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Lot's of good advice above. I will add that at present there is no reason to put any further money into the engine. The rest will come from tuning the car. Dyno tuning may help at this point but it isn't going to help with getting the car to launch and pull the top end.
Don't get excited and start changing a bunch of things. Change one thing at a time then test at the track. Testing without timing equipment usually isn't productive as your Butt Dyno will lie to you most of the time. Your suspension parts are geared toward auto-cross and road racing which are counter productive when it comes to drag racing. Nothing wrong with those parts (I too have PTFB suspension on my 72 so no bias here) just keep in mind they will limit how well the car hooks up and covers the first 60 feet. Putting some 15 wheels and drag radials will help with the launch if your rear end isn't up to slicks. Do you have a drive shaft loop? It will be required to run with slicks. |
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