Agreed Cudaman- We took those off yesterday, front-end had close to zero travel, at most 1.5 inches.
Car now has stock bump stops and thats it- start from there.
I think the rear springs are still tight .
Car doesn't have same power DVW has but i think I can coax 690 out of it.
its an 11.5 tire, 29 inch.
I think 1.38 to 1.42 60ft is possible but, thats just my math and could easily be wrong.
He foot brakes and leaves at 1800 if memory serves.
Hopefully i will get video sent to me of tire hit, car attitude this evening.

btw- front shocks are 90/10 and set at that- i don't think there is enough transfer yet for porpoising to show up but, we shall see.
I put wire ties on rear shock stems to see what movement we are getting there- at least in one direction.

Springs are kinda stiff but I don't see that being that big a problem. Most ladder cars separate when launched so I thinking the instant center could be off (too low), bind in the bars (take one bolt out at the rear, adjust heims till it just slides back in, this is at rest on level surface), make sure pinion is straight or slightly down aiming at the trans.
Might add, make sure driver is in the seat when adjusting that bolt. After all is bolted up adjusting springs or rate separately doesn't work, they work as one on a ladder bar setup, even the front tb work as one so adjust ALL before that bolt goes back in.

Fooling around with a calculator and dream wheel. Looks like about 52% on the nose. That's OK.

Dream wheel and calculators say 675 HP @ 3350 is 9.80 potential in the 1/4 or 6.20 in the 1/8. It's mostly all in the 60'. Car should be mid to high 1.30s at that power to weight. Is it a 3 speed? Good converter with the right stall?

Freeing up the front end was a good move. If it wants to rotate and can't, it will be a turd. The amount of lift can be controlled with an adjustable limiter and/or a good shock. 130 springs is borderline but might be OK at that rear axle weight but you'll have to control the hit with the shock once the car leaves like it should. Pay attention to the separation and that it's not crushing the tire at the hit.

thanks Cm:
He has strange single adjustable back there right now- brand new.
So your math says we are close with 150 lbs springs?

converter is new FTI 5100 stall, we could move it to 5500- we have one free re-stall.

4.30 gear, rollerized 727- all good parts.
air isnt good here.

My dumb ass is better at helping than actually racing that's for sure........it will come around and that twin blades pretty bad azz as well..........

A 150 will hold the car up at ride height and should be compressed some. So will a 130, but I expect that would really need to be wound up. The difference is the lighter spring will be compressed more. That will store more energy to make the suspension more "lively", easier to separate and apply the tire. This can be useful on a mild combination that needs help. More power, more gear - it doesn't need the help. It can get to be too much and beat up the tire.

We have 170s on a car real close to your deal weight wise, but it's violent combo with quite a bit more power and we're also using a real good shock to control it. It doesn't need any extra help from a lighter spring.


I think the 150 is the right choice. But, you can put a 130 on it and see how it works. Not like it can't be taken back off. Lord knows I've tried enough stuff that didn't work...but knowing what doesn't work is as valuable as knowing what does.

What is the compressed length of your 150 spring at ride height?

cant measure as car is in the road .

Haven’t read the whole novel yet, but our ladder bar Duster has 12” 120’s on it.

Do you recall how far the nut was wound up the shock?

My 125# put the shock very near the center of the travel at loaded ride height with almost exactly the same weight on the rear.
Doug

2+ INCHES CM
Car moved my wire ties up 1 1/4 inch
12inch spring
I can get you the data when track opens.
rough night last night, really bad Oklahoma air/ thunderstorms were rolling in and hit 15 min after last run, video showed car porpoising on launch, couldn't see tire well in video but, best i could see, it looks like 12 lbs isn't flattening the tire out.
Honestly don't think there is enough transfer and holding it to squash tire.

Im trying to figure out jetting now, car lost over a tenth, 60ft went up badly.
AFR went from high 12, low 13 to 11's.
sheesh.

Rusty what are the rear shocks set at?
You could very well improve how the car works with a DOUBLE adjustable rear shock. Would not be a bad idea to put them on the front also!!


Mike

2 inches is a fair amount of compression. 130s would have to be compressed another 1 1/2" to hold the car up. Don't think you want to go there.

I assume the shock is about 13.75 or so installed at ride height?

It's porpoising because it's trying to pick the nose up and can't. It's like your rear end when you're trying to pick up something up from the floor that's too heavy. The car is rotating around the front spindle. I'm assuming the travel limiters were taken off already?

If this thing has that much power, something is off somewhere. Unless it's completely blowing the tires, this thing should be way quicker, even if some of the adjustments are not quite right. What's it MPH?

Cm: Im guessing as to spring compression right now- race got cancelled due to weather and he just wanted to load up and come home.

Im certain of the 1 1/4 shock compresion.

Yes, that power is real, dyno we use is from a known engine builder- very conservative, heartbreaker for newbies type deal.
Its primary purpose is engine builders test bed for engines he is contracted for- Fast cars.
Chassis dyno confirms engine dyno and vis-versa.
In this case, how we confirmed we had to much chassis loss/ converter issues etc.

Yes, car isn't right yet.
Not blowing the tires off though, may be crushing drivers side, couldnt get a picture.
The way the porpoising looks, part of it may be drivers tire may be getting crused, going round, getting crushed and then standing back up and out, part of it looks to be shock too loose, not controlling extension/separation- need to turn them up, slow extension down.

Other than that, I'm kinda stuck unless ladder bars are in wrong hole - they are parallel to the ground, middle hole of range.

Front end- light torsion bars, 90/10 adjustable shock on 90/10 setting.
No limiters other than the bump stops are 3/8 extended ( I think that needs to come out, not sure they don't need to be shorter even.

Guy has a big points race next weekend , lot of cars will be there etc.
Im going to go unless something crazy happens that way i can get video the way i want it and get data live and after the runs during test and tune.

We did put the HHR fan on it and that helped a lot with temps.
Car was way down on power, running really rich in that air.
Air density was 4000+ ft .
89- 95 degrees temps and humidity from 55 to 80 percent because weather moved in we didnt expect- wasn't in forecast until they were close to event.
Air actually got worse as temps cooled because water stayed at 119.8.
At least, according to what i have learned so far- thats why carb went so rich.
Two carbs were tried- both went hard rich.

70: Rear shocks are strange single adjustable- brand new.
Thats what was spec'd out when he had the ladder bars put in .
Guy has spent a goodly sum of money in last 18 months:
New rear-end housing, back brace, three driveshafts, tail housing/sprag/trans rebuild twice, moved from 4.10 gear to 4.30.
Ladder bars, springs, new shocks from and rear, new converter, fan etc, etc.

Not much faster yet, but straight, consistent, safer - yes.
Its there, we just have to figure out how to find it.

Air is hard on us down here- its 101 degrees with 50% humidity outside my shop, 29.75 at 544 ft above sea level.

Wallace calculator says:

Your 1/8th Mile ET is 6.62
Your 1/8th Mile MPH is 110.57
Your HP Correction Factor is 1.11
Your DA (Density Altitude) is 3,244.10 feet
Your DA (Density Altitude) is 988.65 meters
Your Air Density Index is 87.8 percent
Your Grains of water is 153.13

Cm- Mph has been averaging 104-105 1/8 mile
146 60ft
6.56 et

ez 440-1 cnc max wedge
12.5 comp
indy single 4 max wedge
holley 950 hp , rebuilt by Pro systems
673 hp @6300- nice long curve ( 599 @ 5200 and still pulling 624@6600 , tq is 662 @ 4600.

I just got an LM2 as well as an AEM fail safe - have it in his car to log runs, we will tune with the LM2.

Get AFR straight this week will help a lot and if we can get chassis to work-nice hotrod!

Thanks

Your P/W is very similar to my old race car. Best ever 10.13@131. I've learned a little about stuff since then. My take is there is not a ton left in your set-up ET wise. Consistency, yes. What I've learned; converters can be looser than what you think. Shocks can be tighter than what you think. Rear gear has little effect if it's close. Air pressure can be higher than you think. Tubes are worth a lot. Lightest springs/torsion bars that will hold the car up. You may not need Santuffs, But the better the shock the more consistent the car. Video from the side is invaluable. Do I know it all? Far from it. But the car was good enough that it went 35/36 rds, 8 races/7 wins before going red last Saturday.
Doug

and there ya go DVW.

I think there is a little power left to be found, definitely chassis tuning to be done- no doubt on that and then she is what she is- just win rounds being consistent.

Car did well this weekend in Denton.
Really bad air but, with Dom’s help, we were able to get within a 10th of cars best.
Everyone else in this class was over a 10th off, we were under- thank you Don!

Springs- man, we are getting close guys.
Took another 3/8 inch of front end limiting out which put it at stock or really close.
Car is leaving wheels up, but even tightening up the extension, it’s dropping back down to fast, unloading the rear .

Anyone know where I can get 140 and 130 lbs springs?
I had hoped Strange and/ or Hyperco had them so I would be working with apples to apples.
We are still only compressing the shock 1.250 , I think 140 lbs springs or, 130 might get us to correct in shock travel and thus shock control.
I like to make small changes, one at a time and record them.
All the spring catalogues I have or see online jump from 150 to 125 and I fear that might be too much and even if not, will wonder if that “ just right” spot was missed.

We did hit the tire harder, enough so that we had to add air and didn’t have more spinning, tire stayed a bit more round and 60 ft picked up slightly .
My “ gut instinct “ is: If I can get a bit more chassis rotation and hit on tire/ control of the release of that hit, we could raise both tire pressure and rpm at launch a bit.
Leaving now at 1800 rpm.
I think 22-2500 is possible with good paddles/ no crush and solid hook.
Rpm graph from runs indicates ( to me anyway) we might need a tad more tire slippage to help driveshaft speed.
I shot video of each launch for tire and car attitude.
Good front end movement now, still not much on the rear , jerking tire up, dropping down pretty fast, loaded and unloaded tire on drivers side and car “ try’s “ to pull tire off ground again when tire reloads .
Right now car looks more like a lever action than a chassis rotation- if that makes sense.
It’s my belief if I can get rotation and control extension , we can carry the tire, plan driveshaft speed and drop 60 ft times a good bit .

Thanks again for all the help and any more ideas you might have.

Rusty