Looking for 60' help...suggestions?
 

I'm wanting to get my 60's back to where they were last year before all my changes. I made a lot of changes to help my car run more mph and lost some 60'. Last year, my typical 60' was around 1.52. This year I'm at 1.60ish.

I went from a too loose converter that flashed to 4700 (but slipped big time at the stripe) to a Continental 10" that flashes to 4000 but is a lot tighter down track. Torker II intake to a Northwind. Q850 carb to a Q950. SFT 255/266 106 LSA 103 ICL cam to a street roller 254/260 112LSA 108 ICL. I've only ran it in the 1/8 mile and 60's are about .08 worse, ET is really about the same, and mph is up about 2 mph. I know the extra mph will really help my 1/4 ET, but really want to get my 60's back down too.

The car dead hooks and it doesn't lift the front or separate the rear excessively. Carb is pretty much dialed in. A/F graph looks pretty good, maybe a little rich in low gear. Launching on the footbrake from about 1800. Not sure where to turn next. Will suspension tuning help on a car that doesn't spin or have any excessive lift? Thanks in advance for any suggestions!

Video of front and rear wheels: (third pass it did spin, but that was my fault)
https://www.youtube.com/watch?v=RBuwpc-irVU

A/F ratio and RPM:
http://i61.photobucket.com/albums/h6...pshxztz2r7.jpg

Try leaving from idle or just above. Maybe if u hit the convertor harder the 60 ft will improve. It may b that the 700 rpm stall difference just had a negative effect.... If ur happy with the increased mph, maybe the convertor can b loosened slightly, for a compromise?

You could also try advancing the timing, especially if u have the ability to retard it in high gear. Sometimes that helps 60 ft, at the expense (sometimes) of mph. If u have the ability to retard you may b able to gain back in 60 ft and keep your new improved mph.... All kinds of stuff to try.

I tried leaving from idle with this converter and the old cam. It slowed the 60' just a bit and killed my reaction. I'll try it again with this cam and see what happens. I also thought about locking the timing to see how it affects my 60'. Right now its 25 at idle and 38 total all in by about 3000. I cut my collector extensions from 24" to 12" (now 18" total collector length) to try that but races are cancelled tonight so I'll have to wait to see what that does.

I run mine locked and I drive it on the street.... The extra advance would probably help. I have a digital 6 box that has a start retard though. I wouldn't recommend it without.... I have a high speed retard also, though I haven't tried it yet.... I could see where you might benefit from more advance down low and less in high gear. Bottom line is u gotta try everything before u know what works best.... Good luck, I hope u find ur missing 60 ft.

I lost over .05 in mine by switching to a power valve and had too much fuel in the take off. I might need it back when it's all straightened out but did make a big differance for now by just putting a plug back in.

Do you think the extra 700 rpm of flash contributed to the better 60ft?

Just a few things:
Yes, as hooking doesn't always mean that the suspension is working. A properly tuned suspension will hook AND motivate.
I would also lock the distributor.
The changes you made and are making are taking the low end power out of it, causing you to run slower short times.
I also want to add, don't tune the engine for max power according an A/F meter. It can be a little misleading. :2cents:

If the car dead hooks, as in no wheel spin, I would try loosening it up. A little spin will bring up the revs to get you closer to peak sooner with the side benefit of being easier on parts than a dead hook.

I will add that this also helps with a converter that is way too tight, as a little tire slip will help put the engine in its power range faster, helping to motivate the car as well. As long as it doesn't overpower the tires.

Firechicken-
Since the changes you made, have you tried shifting a little higher?

Thanks for all the input!

I don't have a start retard but I do have my starter and ignition on separate switches so I could get the engine spinning then hit the ignition if I need to.

That's interesting. Blocking the primary power valve isn't an option for me with the amount of street driving I do.

Absolutely! That's where most of my 60' went. I thought about trying that converter again but it just slips too much down track and kills my mph. It was slipping 15% at 6300 and 120 mph.

That's what I'm looking for. Some ideas for things to try with the suspension that could help get the car rolling better even though it's hooking good now. the suspension is stock except for cheap Summit 3-way adjustable shocks, Moroso trick springs, and Caltracs.

I'm running M/T ET street radials. If they slip at all I have to lift. They either hook or they don't....there's no in between. When I went to them from a bias slick, I picked up .05 in the 60', .10 in the 1/8 and .15 in the 1/4.

I did change my shift points and it likes a little more rpm now. I knew going in these changes would take some off my 60'. I just need to figure out what's going to help me get my 60' back down where I think it should be now.

I would definitely lock the distributor, set it and forget it.
I don't know what the hood clearance situation is like, but if you can fit a 1" (minimum) aluminum HVH Super Sucker spacer, I highly recommend it.
I agree, I wouldn't remove the Power-Valve up front.
Converter is a huge deal and will definitely cause you to lose the 60 times, and although 4,000 isn't shabby, I would look into having one built that will net more rpm on launch, yet remain tight enough down track to keep the slippage down. 15% is a lot and is definitely NOT the norm for a street 10". Sounds to me something might be up with it. There is more to a converter than just rated "stall" or "flash" rpm, and when built right, you CAN see that best of both worlds scenario.

If you get the opportunity, try tuning for power at the track, with a little less focus on A/F ratio. You will be surprised. Most guys who rely too much on that wind up being safe but very conservative.

Two other areas you can look into, would be switching to a bit more gear (which you can test by bolting on a shorter tire, like a 26") just to see. And the other area would be adding 2 more degrees of advance to the camshaft if you decide to dive back into the engine. Changing camshafts like you did from very similar duration numbers to that much wider lobe separation alone would kill enough bottom end to lose 60 ft, giving it a little more may just bring it back without going too drastic with the rest of the drivetrain..

As for suspension, seems you need to hit the tire a bit harder to get that car motivating. A few areas to look at would be actual Pinion angle with driver in the car, what hole the Cal-Tracs are in, and what is done to the front for weight transfer.

Just a few ideas, hope this helps.

I've got a 3/8" open spacer under the carb and that is all that will fit with my air cleaner. I ran it once without the air cleaner and surprisingly it lost ET and mph. A/F ratio (surprisingly) didn't change noticeably. I thought about finding a different air cleaner that would allow a 1" spacer.

The 15% slippage was with my old Freakshow 9 1/2" that flashed to 4700 and would only drop 500 rpm on the shifts. My current converter is a 10" Continental reworked by Lenny at Ultimate Converter concepts. It was built for my current combo. I haven't ran it through the 1/4 yet but it drops 1000 rpm on the shifts and dropped my 1/8 trap rpm. I'm sure it will really help me on the upper end.

I do have a set of 4.10 gears but I really want to keep the 3.73's. It makes the 250-350 mile drives between tracks on Drag Week a whole lot more bearable.

Caltrac bars are in the lower hole. I had them in the upper hole before and didn't notice any change in 60' when I moved them to the lower hole but it did decrease the amount of separation in the rear on launch. I'll see if I can check the pinion angle. Isn't about 4 deg. down relative to the driveshaft a good starting point for a leafspring/Caltrac setup?

Here's a video of mine last race, I added a small gap on my bars to hit the tires harder, upper hole, as I don't have a trans brake, but I am using my 2 step, and foot braking leaving at 2300. It was hot 84 and 68 dew point that day, with next to no prep, I have my rear shocks full loose on ext, and full tight on comp, tires at 13.psi, 60 was 1.50 ,but it was stuck with the above track conditions, should go low 1.4 in much better weather. Have u seen if new conv is actually flashing to 4000 on leave?
https://youtu.be/Rbjua04ALds

I think 4000 flash is a little low for your combo. I think you were right in the ball park with 4700. Just needed a better converter IMHO. Just an example of a combo that don't sound right but was right......my 69 bird had a d- port solid roller motor that was done at 5900-6000 rpm. Sweet spot on the converter was 5000 rpm. I put some nitrous on it and had the converter tightened to 4700. It hurt performance on motor. Kenny Ford at PTC was magic for me and very affordable.

Nice video Darby. You put the spank on that el less car!

Vengeance is providing some great suggestions. I've been doing this along time and I can tell you improving 60' times is all about numerical gear ratio, converter, suspension and tires. Given this is a "street/strip" combo it will take considerable testing to find the sweet spot. Another suggestion is to invest in an overdrive unit or a 4 speed auto which would allow you a lower numerical gear ratio without drivability compromise.

4000 is what my LM-1 shows on the graph. Have you ran your Caltracs in the lower hole? What difference did you find switching from lower to upper? Calvert suggests that the bar should be close to level with the ground. That's the lower hole on my car. I also would think the lower hole will push up on the car less and not waste as much energy lifting the rear if it's not needed for traction.

I'm 100% sure a lower gear and looser converter would help my 60' but I'd really like to optimize what I have. I think it's realistic to think I can reach my goal of getting my 60' down into the lower 1.50's or upper 1.40's where I think it should be with some tuning. I'm just getting a little short on time for trips to the track for testing different things before Drag Week. My goal for this year is to finish with an average in the 10's. I'm right there now, but the weather will play a big role in whether I can run in the 10's consistently or not.

You made a bunch of changes, all in my professional opinion, raised your power band. Not just peaks, but the whole power range, yet you switched to a MUCH tighter and lower rpm converter. That is why your short times fell off.

Don't confuse Loose/Tight or Slippage with Flash rpm. You SHOULD be back at that 4700-4800 number (which is fine for middle of the road) with a converter that isn't slipping that much. Combine the higher flash rpm for launch and its ability to let the engine accelerate, with a bit less slippage, and see where you are at. Super tight converters that flash too low in rpm will not accelerate the best down track. Every time you shift you are pulling the engine down too far as well and it can't recover fast enough. If the slippage in this new converter is good, then you just need the higher rpm to get the engine into its "HIGHER" power range which will allow the car to get out faster. You just can't expect to raise the power band and run a lower rpm converter and expect it to perform better.

Regardless of suspension tune and minor adjustments for now..worry about it when you optimize the combination. :2cents: