Still chasing 10s. New PB 11.38@123.5mph

[acammer]

Well - the quest to crack the 10s with an SBE all motor stick car continues to be a long, winding road for me. After almost three years to the day, I finally made it back to the race-track this past weekend to try out the new Max Package combined with the 9" setup in the car now.

I have some mixed emotions about the day - I set the goal as "new PB", but I think in my mind I wanted a 10.99. I did manage to trim several tenths off my prior 11.67@119 - so I accomplished my goal, but that low 11s slip left me aching to make some more changes. I was really happy about how the car is launching and running the 60' - with a 3,970lbs race weight I think a 1.56 in a stick car is pretty good. No doubt the 4.63 gear is doing exactly what I wanted from it there.

I think there is probably at least another tenth or two in the car as it sits - the shifts were (deliberately) slow, and a I shorted the 1-2 shift all day, still getting used to how quick this thing comes up on that shift at the track. I don't think I'm gonna get a shot to run it again this year, unless I trek down to Fall Brawl - but that's a long haul, and 50/50 on we've seen snow and salt by then, which will make it a no-go.

So - what's next in 2023? Probably some weight reduction. The car has some obvious places to trim weight - I think the front sway bar, exhaust, and a light weight battery can probably get me close to 100lbs, and maybe the driver can try to drop 50lbs. Then, I need to do something with the rear diffuser - either close in the area back there, or get a rear bumper with no diffuser for the track, as the factory GFX diffuser is a bigger parachute than even the standard diffuser. I've heard 2-3mph and 1-2 tenths can be gained there, so I'd like to think those couple tweaks could have me right where I need to be.

Some folks are surprised that we only saw 124 mph out the back with 550whp. That dyno number was before the rock crawler gear ratio and 9" rear end, and I'd be willing to bet we probably ate up 10-20whp there. To me, that's worth it - I've tore up enough stock stuff to know that I'm never going back, even if it hurts power. I chalk the rest up to the aero situation above.

[NoDakZ/28]

Congrats! That 1.56 60' is damn impressive for our heavyweights and even more in a stick car. Be patient, it'll come!

[Chris49066SS]

Congrats! Have you thought about losing the wiper fluid reservoir, the crash bars, and the seats too? The exhaust does add some weight for sure. I need to do Aerospace brakes next, then Welds. You're almost there. Really impressive 60' especially with a manual. Damn.

[acammer]

Originally Posted by Chris49066SS

Congrats! Have you thought about losing the wiper fluid reservoir, the crash bars, and the seats too? The exhaust does add some weight for sure. I need to do Aerospace brakes next, then Welds. You're almost there. Really impressive 60' especially with a manual. Damn.

Yea, passenger and rear seats were out. Probably could ditch the wipers/motor/reservoir. Not sure how I feel about crash bars, I put like 5,000 miles/year on this car. Probably less now, so maybe.

Thanks for the encouragement on the 60'. I figured if this car went that good in the 60' it would definitely make it in the 10s, but I think the weight is just killing it too much. 9" robs some power, rear bumper thinks it's a parachute, I can see why it's still not doing all I want it to. There's always next year!

[Tajefe Couple]

Nice Andrew, especially that 60' with a manual, impressive sir!

I feel you on the weight reduction, I personally could drop 75lbs and gotta be right around 4000lbs since the only reduction I have is the drag pack. My car has more in it to but can't ever seem to find it. I blame my DA at the track around here usually 2500-4000 ft and never any good air. Just come to the conclusion until I have you all at GPI supercharge it just not going to see 10's, constant 11.4's though.

Curious do you know what the DA was at the track the day you ran.

[acammer]

Originally Posted by Tajefe Couple

Nice Andrew, especially that 60' with a manual, impressive sir!

I feel you on the weight reduction, I personally could drop 75lbs and gotta be right around 4000lbs since the only reduction I have is the drag pack. My car has more in it to but can't ever seem to find it. I blame my DA at the track around here usually 2500-4000 ft and never any good air. Just come to the conclusion until I have you all at GPI supercharge it just not going to see 10's, constant 11.4's though.

Curious do you know what the DA was at the track the day you ran.

Thanks. I'm still unreasonably frustrated in my head with the performance. I set myself up for it for sure!

The DA was right around 1200'. Was hoping for better, but it has been unseasonably warm. We'll take it, but if I can get it down to Fall Brawl and run in some -1000-1500' air, that would get it pretty close.

Give me a shout and we'll get that supercharger lined up!

[1JEWLDSSRS]

Dang Andrew, that's pretty good sir!! That 60' is pretty dang impressive!! You are almost there. Won't take much. I do believe that that rear diffuser would be a big problem as it really does catch a ton of air. Have you maybe thought of fabbing up a thin piece of aluminum that you can attach to the underside of the car, then to the diffuser? Kind of like a rear belly pan so to speak. Car sound amazing too by the way. Don't beat yourself up about it. We all do things like that, we expect too much, then when we don't get there, get disappointed. But rest assured, it isn't going to take too much for you to knock those 3 tenths off that slip. Good luck bro, and stay focused and positive!! It's coming..

[acammer]

Originally Posted by 1JEWLDSSRS

Dang Andrew, that's pretty good sir!! That 60' is pretty dang impressive!! You are almost there. Won't take much. I do believe that that rear diffuser would be a big problem as it really does catch a ton of air. Have you maybe thought of fabbing up a thin piece of aluminum that you can attach to the underside of the car, then to the diffuser? Kind of like a rear belly pan so to speak. Car sound amazing too by the way. Don't beat yourself up about it. We all do things like that, we expect too much, then when we don't get there, get disappointed. But rest assured, it isn't going to take too much for you to knock those 3 tenths off that slip. Good luck bro, and stay focused and positive!! It's coming..

I agree - it's close. I changed a LOT of stuff, and just figured surely if I spent enough money it would just do what I wanted right away. Classic knuckle dragger thinking for sure. I've seen guys do more with less - I just need to commit to some real weight reduction and it would already be there.

I need to decide what I want to do with the cat-back, and if I just remove it entirely and dump the exhaust after the x-pipe then I think I could look at doing a rear belly pan to try to help the aero out back there. If I find a second rear bumper to hack up, that's probably gonna be my first move.

And then I keep looking at nitrous kits...

[Chris49066SS]

I really do hear ya on that with cracking the 10s NA, I am so close I can taste it, definitely frustrating, but that 60' is really promising. With some better air, dumps after the X pipe, the right tire psi, you should get it though. Then yeah theres the washer fluid reservoir, like you had said. Then theres a bunch of stuff to strip out of the interior, I have started to gut mine. If you do dumps, make sure to get a video!

[Ashen 6.2]

Your car is launching really well and sounds freaking awesome! Some days at the track will test the patience.. lol.. Ive had my share of those as well. But as long as you're adjusting and learning your times will continue to get better.

[Pkeen]

Hey acammer I see in your sig your rwhp is 551 ,what's your rwtq ?

[acammer]

Originally Posted by Pkeen

Hey acammer I see in your sig your rwhp is 551 ,what's your rwtq ?

463wtq. This was the cam only setup VS. the Max Package. This was before the 9" - you can subtract probably 35whp with the 9" - just guessing but will test that at some point.

[Pkeen]

That's cool ,making some good power! Why does changing to a 9" use more power than the stock rear?

[acammer]

Originally Posted by Pkeen

That's cool ,making some good power! Why does changing to a 9" use more power than the stock rear?

Hypoid offset difference. The 9 inch "Ford" rear end (mines a Strange) places the pinion lower on the ring gear compared to most standard rear ends. This creates more tooth engagement - you can see (picture below) that 9 inch pinions are much larger for the same ratio than other similar diameter ring and pinion sets in the same ratio. That increased amount of tooth engagement has two major implications for the rear end:

1. Strength - all that extra tooth engagement makes the 9 inch much strong than other gear sets. It's the "go-to" rear end in drag racing for several reasons, but top of the list is durability.
2. Friction - that extra engagement costs you substantial amounts of sliding friction. The result is a rear end that consumes more input power for a given output.

So, the 9 inch makes an intentional compromise in efficiency via increased friction to achieve a stronger, more durable design.

Additionally, the 9 inch has a third pinion bearing on the inboard side of the ring gear, which supports the pinion shaft on both sides of the ring gear. This was originally done because the outer pinion support on a 9" places the two bearings fairly close together and would struggle against twisting forces. The inner support adds a ton of support in the right place for the pinion shaft, and really limits any deflection potential you could have from the pinion shaft. But again, it's another bearing, and trades away efficiency lost to more friction for increased strength.

I've read tests results all over the board on how much efficiency a 9 inch gives up, and the answer is probably somewhere between 1 to 5% - and of course depends on which rear end you're comparing it too. Our OEM SS rear end is a weak turd, but it is extremely efficient, and so I estimate my losses are on the far end of that scale toward the 5% mark. I flat out guessed when I quoted 35whp above. Doing the math, 5% from 551whp would be 523whp, so maybe more like a 25whp loss. Still, a substantial amount. I have some "before" data with the Max Package and stock rear end on a local dyno, I intend to obtain a second result with the 9" to better know exactly what it cost me. I know it added just over 40lbs of weight.

The 9 inch has other advantages - you can changes center sections fairly quickly so could potentially have backup or even different gear ratio center sections available to swap in at a racing event. They are also the most prolific drag racing rear end by far, so parts for modifications and service can easily be found.

For me, I have had extensive problems with the OEM rear ends (and axles), and I am confident that I would continue to have problems with those if I continued to drag race the car. I took nearly 3 years off while saving for this rear end and engine combination, and while it's not quite where I want it yet in performance, it is an incredibly durable setup that I can run hard day in and out without worries. If the S60 was available with the gear ratio I needed I'd probably be running on of those as it should be strong enough, and more efficient. But, for the ultimate in strength and flexibility, the 9 inch was the go-to.