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Bracket Talk Bracket Talk Forum Tech Talk - by Abruzzi Dragster header question SBCGo | New | Find | Notify | Tools | Reply | |
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| DRR Trophy |
In two weeks I will be able to go to a test and tune where I will be able to run the full quarter mile. Hopefully I will be able to get better data. Then I will make a plan. Right now I have a few 1/8 mile races to go to. Don't get behind me,I'm in the slow lane. | |||
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| DRR Top Comp |
It's not header problem, it's a gearing problem. Like I said previously you don't have a cookie cutter dragster combo where you're working with 7,800 - 8,000 rpm's as most, you're working with 8,800 rpm's that's a whole different ball game. You can't just change the final ratio because you'll have too much starting line ratio over challenging the tire. That's the reason for the low gear adjustment as well as the final. I'll say the converter slips 1/4 mile 12-13%, that's A LOT of multiplication to give up, it'll obviously hurt performance. I did the equation with all the different scenario's I posted, you have the perfect converter in the car now once the gearing is optimized. If it ends up having the capacity to run above 175 mph once optimized , the 4.88 with either a 1.64 or 1.58 will be the hot ticket. Run it 1/4 mile let us know the results, I'll run those numbers to better hone in on the best option. My guess is it'll go 170 mph leaving a lot on the table converter slipping 12-13%, depending on exact tire growth. | |||
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| DRR Trophy |
Like I said. Let me get some accurate data for the quarter mile. I have not made a good pass this year. Other than last Saturday in a first round loss. This way I can see what the convertor is slipping at in the quarter. Anything else is just a guess. Don't get behind me,I'm in the slow lane. | |||
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| DRR Top Comp |
No it's not a guess, it's math. I've done the math. If it goes 170 mph converter will slip 12-13% If it goes 175 mph converter will slip 8-9% Either is giving up quite a bit of power at the back tire. The only way to adjust any 7600 converter in your car is gonna be as I suggested. It's all a guess for you. Not a guess for me, it's math. It's the same math converter companies used before racepak. I don't need racepak, I know the math. | |||
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| DRR Trophy |
Scoop, I have a Small block Mopar similar to what you're describing, but only 358 inches. It makes and HONEST 843 hp on the dyno. In my 4-link dragster, we have been 4.67 at 146 (8900) with a 5.67 gear and 7.45 at 179 (9050) with a 4.71 gear. The secret to making these motors run is "freeing up" the driveline to allow the little torque we have to move the car and then the Hp takes the car to big mph. All of tese performances are on a 33x10.5 tire and all required a 7" converter. I noticed you said you'll be testing this week, maybe at MG? If you are, stop by and I'll be glad to chat with you and offer some ideas on your tune up. Mike Novitsky 193E Silver and Black Dragster | |||
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| DRR Trophy |
I will be at Mason-Dixon on Sunday for a points race. Then try to catch a test and tune the following week or If I don't work on Friday will be there Friday night. I have some other tuning issues with the carbs that I have to work on so I can get a clean pass the whole way down the track. Bob J Don't get behind me,I'm in the slow lane. | |||
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| DRR Top Comp |
That's some excellent insight to what Scoop is gonna be able to do with gearing. You have the 7" converter slipping around 6% both 1/8 and 1/4. This means scoop's 8" diode converter will slip 1% at 180 mph crossing 8800 4.88 gear. Gotta adjust low gear too though 8" converter. I'd do a 1.64 if it doesn't over challenge the tire now 1.80 x 4.57 = 8.22 SLR 1.64 x 4.88 = 8.20 SLR How we originally figured. | |||
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DRR Trophy |
I run a 400 inch small block with 18 degree heads in my FED and I do agree that you do need a 4.86 gear with that 33 inch tire to be quick ! I also run a 1.69 low gear ! It was hard to get it to leave well with the 1.80 ! 7 inch converter that stalls at 8200 ! Mine has twin terminators on a sheet metal intake ! My first thought when I saw your post is that your carbs are too big ! A big carb might show more power on the Dyno but might be quicker on the track with 2 smaller carbs ! Just my 2 cents ! | |||
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| DRR Top Comp |
These high rpm combo's are interesting, lots of potential for flying if you can get everything just right, imagine a bigger set of headers, geez, it would have killed it but I think Scoop may be ok 2" 2 1/8" step at 8,800 rpm. https://youtu.be/FZ6zwnyDwUg We have a 427 23 All Pro raised runner sbc we've been working quite a bit with the converter we're gonna spin 8,500 rpm plus, 1" lift cam. I have two different transmission pumps and input shafts ready for the car we're gonna test to see which configuration the converter responds best , a hair more restrictive ringless input and pump, the other with rings with several mods in mind. This thing will be around 1150 1200 hp with the spray. I know exactly how I wanna run this thing so with the parts we have ready to go it'll only take a few licks to be optimized. We're just waiting on some cooler weather they don't typically run these 275 radial tire cars in the summer. Looks like Sept it kicks off. Hey, thanks for your input Bill, interesting! I dig these high rpm combo's. Bad azz 9" nitrous converter, kinda the same concept as 7" n/a high rpm. This is the perfect converter for what we're doing around 140 mph 1/8 mile 3,000 pds.  This message has been edited. Last edited by: Mike Rietow, | |||
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| DRR Trophy |
New gears in the rear and trans will happen over the winter. Now I just have to work on getting this thing to make a pass with out turning the spark plugs black. Bob J Don't get behind me,I'm in the slow lane. | |||
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| DRR Top Comp |
I can have all three things done by lunch tomorrow for a small fee. Kidd'n  | |||
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| DRR Top Comp |
9,000 rpm nitrous sbc valve train, 1400 on the seat.  | |||
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DRR Pro |
Scoop I would definitely look at your black plug issue first, that will kill power at the start for sure. My dragster is a tick over 1800 lbs currently, 461" SB2.2, single carb, best has been a 4.71 @ 145, 7.54 @ 175. 1.04 60'. 4.30 gear, 16x32x15 MT's. Stall has been 6500-6900 with different converters, no change in performance. What compression, what plug? What carbs?  Mark Whitener RFD Heads FTI Converter Fab Shop Headers Home built 2 circuit Dominator :-) www.racingfuelsystems.com ____________ Good work isn't cheap and cheap work can't be good. | |||
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| DRR Top Comp |
So you shift 7800-8000rpm and cross 8200-8300-8400rpm slipping 5-6-7%? I'm guessing based on stall. I presume based on stall I should say. Realistically, Scoops combo should run in the mid- high 4.60's. It's really a 1/4 mile combo though.This message has been edited. Last edited by: Mike Rietow, | |||
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| DRR Elite |
You gentlemen are not afraid of rpm. That's for sure! That's hustling. Foxtrot Juliet Bravo | |||
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| DRR Trophy |
Don't get behind me,I'm in the slow lane. | |||
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| DRR Pro |
3" choke is not helping. What was the engine dyno'ed with? Mark Whitener RFD Heads FTI Converter Fab Shop Headers Home built 2 circuit Dominator :-) www.racingfuelsystems.com ____________ Good work isn't cheap and cheap work can't be good. | |||
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DRR Pro |
I turn my 665" 8000-8200 Mark Goulette Owner/Driver of the Livin' The Dream Racing dragster www.livinthedreamracing.com "Speed kills but it's better than going slow!" Authorized Amsoil Retailer | |||
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| DRR Trophy |
The engine was dyno'ed with a 2 in to 2 1/8 in to a 4 in collector. Don't get behind me,I'm in the slow lane. | |||
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| DRR Trophy |
I put my old headers on that have the same primary tubes just a straight 3.5 in collector for this weekend. Don't get behind me,I'm in the slow lane. | |||
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Bracket Talk Bracket Talk Forum Tech Talk - by Abruzzi Dragster header question SBC
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