That is solid. What mods are done to the car?Originally Posted by dbb2797
That is solid. What mods are done to the car?
Pypes Super system exhaust, Pypes Long Tubes, Circle D 3600 converter, Hoosier Drag Radials, Lightweight race seat, rear seat delete, anti-gravity battery, CJ springs, Strange Double Adjustable rear shocks, Koni adjustable struts, BMR extreme anti-roll bar, BMR adjustable UCA, Boss 302S LCA, CJ Intake, CJ CAI, CJ mono TB, The Driveshaft Shop DS, 4.10 gears.
I think I can still squeeze a bit more out of it too. I've been debating going to a higher stall converter next year too. And I've been analyzing going to a longer gear. But I can't find the right combo for a gear that gives me a good RPM at the stripe for both 1/8th and 1/4. While the 4.10's are steep, I am in the upper band RPM at the stripe for both track lengths and I race both frequently.
I think the 4.10's are hurting you. You won't find a ratio that is optimal for the 1/8th and the quarter. With that intake I would move to a 3.31 rear gear. I would leave the converter as is for now. One of the 10 sec. N/A cars I tune is running a 4c.
Do you know if the 10 second car is able to stay in 3rd at the stripe for the 1/4? Using the RPM calculator with my 27" tires, it looks very close. It shows 119 MPH at 7500 RPM and I'll cross at right around 120 MPH. I suppose I could spin it up to 7600 MPH and try to wind out the gear.
Yes it crosses at the very top of third at 125MPH; 28" tire.
With the Boss or CJ you will want to shift it at 7,600- 7,800. You should have plenty of room with more RPM.
Thanks for this info. I also suppose I could shift a a little bit earlier for 1/8th mile racing. I don't think the 3.31's would really help much in the 1/8th since I'll have to shift to 3rd either way. But I also want to make sure when I'm crossing the stripe that the converter has caught up and isn't slipping too much. I'm thinking this is where a higher stall converter could help. The fallback RPM currently is about 1200 RPM's and takes about 5-6 MPH to catch up. With a higher stall I may be able to drop a few hundred RPM's off that giving me more room.
Don't read into the converter stall too much. Lock it after the 1-2 shift and leave it locked from there on. Focus on getting your 60' down and it will carry all the way down the track. 2 step and 2 relay transbrake should be on your next list of mods.
Leave shifts at the RPM mentioned for optimal recovery.
Oh I should have mentioned that I do have a 2-step already as well.
I understand what you're saying about the shifts. But the problem is that I bracket race. I can't have the car shifting into 3rd gear 50 ft before the finish line. I virtually never cross the stripe on full throttle. So I need room to get on and off the throttle, brakes etc. So I need the car fully recovered from the shift, with relatively short fallback in RPM to keep consistency, and climbing back up in RPM's when I start my finish line driving.
I index race myself and never have an issue with consistency however the car is too fast in any part of the year for the index so I tend to race and hit the brakes before the finish as do most in that class locally.
https://www.youtube.com/watch?v=PmvBGz80Fwk
https://www.youtube.com/watch?v=vKsWEvJJpTc
3.31 gear in each video.
Those are impressive runs for sure. And it's good to know the 3.31's do work well in the 1/8th and it shows I probably have a fair amount more I can squeeze out. Is that on stock cams too? The video was a little grainy to read the timeslips too. What was the 60ft on a run or two of them?
Thanks.
Yes stock long block.
60' times in the second video for both runs were 1.46 and 1.47.
For the longer gears, I did the calculations and I came up with up about 10% slip at the fallback RPM shifting from 2nd to 3rd. So actually that's pretty good. I'm feeling more comfortable about the gears now. I'm definitely swapping out my 4.10's over the winter. I think I'm going to go with the 3.25's.
True story, and I can't emphasize that enough. What a piece of junk.
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