That just means the drum wasn’t setup properly or not enough bias was given to the drum. The drum has a shyt ton more surface area to grab on than a disc brake/pad setup. It will 100% hold better IF setup correctly. Drums aren’t used anymore because they heat soak and fade more than a disc. But as far as holding power form a stop… the drum wins.

To get the best of both, guys install dual caliper disc’s on the rears. See that quite a bit on the “foot brake cars” around here.

 

I did modify my rear drums. Used tricks from the Buick GN guys of years past.
changed wheel cylinders, used two long shoes, and a proportioning valve to favor the rears.
The shoes are Raybestos semi metallic.
Surprisingly, it stops quite well even from near 160.

All moot now that I have a trans brake. I’ll prob add discs in the rear down the road.

 

The drums worked perfectly fine and were adjusted correctly. They were stock fox body drums. Again, I put way more on the compound of the disc set up being a good pad and heated correctly after a foot brake burnout. I'll take that all day over a horrible stock compound that likely only gets worse (which you agree) after a foot brake burnout, regardless of contact area.

 

That's cool. Definitely better than my factory fox mustang set up. I've found that converter is much more important than brake clamping force anyway. I also agree that foot braking overall just isn't good and t brake is what is needed. I'm 99% sure going to one this winter as well.

 

Very good. I didn’t mean to be argumentative.

I haven’t had a trans brake since the mid 90’s. And I’ll admit, now that I have one, it’s thrown me for a loop.
😩

 

Simply stating the design of the drum is much better at holding high loads from a stop. I modified my bias. Extended my brake pedal for more leverage, and ran good shoes/drums. So I had great clamping force. (had a big electric vacuum pump assist on one setup that worked great). Also ran a line lock so I didn’t glaze the drum/shoes during burnouts. The brakes will never work as they should if you are doing burnouts without a line lock IMO. I agree a glazed over drum/shoe with no bias won’t hold much power.

 

My intake is an ls6, I have several others to play with but all are "long runner". I'll never run a short runner on this car, they give up a lot of low/mid rpm power.

My plan of attack is to troubleshoot and tune first. Since I got my car back I went from "my first 7875 turbo" with .96ar and 3" exhaust to a G42 turbo with 4" bumper exit (exhaust is in process). I understand where you guys are coming from with the torque converter. If its not getting to the rpm where its making positive boost its going to be a dog. Since my car wasnt making any boost until after 4000rpm with that small hotside I want to try to get the boost in faster first. Chicken/egg? I have an ebc and need to look at it and look for boost leaks, then tune the fuel, I was told its too rich until its well into boost. Then I'll look at timing. If all that doesn't get it I will look at torque converters.

As far as cams go, mine is nothing crazy, its 222/227 @113lsa, -1.5 degrees overlap. Now that I have a turbo that breathes better on the exhaust side I think I can go to 5 degrees of overlap and it won't hurt me. My thought is a stout "truck type" cam with a tighter lsa. I also have some Rhoads Vmax lifters here I'd like to play with.

Cams I have been looking at:
1) TSP Stage 4 truck cam, 223/226 111lsa (maybe go 110)
2) Michigan Motorsports, 225/229 111lsa
3) Custom cam based on Summit 8720r1, 218/227 but with 109lsa, the 8720r1 actually beats Summits next size up cam until the very top of the rpm range and its a tie from there. Tightening the lsa almost always beefs up low/midrange power even more. I think this cam could be a winner, like a bigger Truck Norris.

None of those go over 5 degrees overlap and with the Rhoads lifters I could dial out 15 degrees duration at idle which would make them act like baby stage 1ish truck cams then get full duration back by 4000rpm.

I've used Rhoads on a previous car and liked them. Mike Jones really likes them too if you read through the thread below you'll see his comments. Some might think, why bother, but the car is a nice day daily that I want totally stealth until I hit the gas. Its a toy and I am wanting to play with really getting the response dialed in. If its great or if it sucks I'll share with the group. I may be using Comp Cams XD-A adjustable pushrods to get them dialed in rather then just measuring and getting a fixed length pushrod, I've heard a few people used them and had good results. They don't seem to be very popular though.

https://www.speed-talk.com/forum/viewtopic.php?t=29745

 

Ah yeah you definitely went full boat on the footbrake set up. With all that I can definitely see how they would be better than a disc.

So since I've got the footbrake guys in here, what did you do to keep the suspension from loading and taking all of your movements (anti squat or squat) out while staging? I dialed about 130% anti squat into my car and if anything it hurt me. While lighting the 2nd bulb and getting on the 2 step, you can watch the *** end of my car raise up about 2". By the time I'm leaving on green, it's all gone and i get zero movement out of the rear suspension because it was loaded up during the foot brake 2 step process.

I'm not aware of any way to cure this outside of ditching the foot brake and getting a trans brake. Any input would be appreciated though. I've just recently moved the LCA back up to the stock location to get it closer to 100% AS and hopefully eliminate the 2" rise while staging.

 

That camshaft is 100% NOT your issue. I wouldn't touch it at all personally but there are about 10 things you need to do first to fix your issue before you change the cam.

I would hard pass on those lifters too. First I've ever heard of them. They are not going to fix your issue either. Seems extremely overly complicated for a basic turbo ls deal that a super basic LS7 lifter should be fine in. If anything I would be spending money on a Johnson drop in.

You need to KISS on this issue, not start blindly changing parts and throwing more complicated stuff at it that will only add to your potentially problem solving path.

 

I dug up a launch video of my car. The rear rises on the two step. The front stays level if I keep the rpm at 3000.

I’m on leaf’s with CalTracs and you can’t dial in antisquat.

So yes, the trans brake is the solution.

Off subject for the OP here though as he isn’t building a drag car.

 

I think converter plays a big role in this.
The converter in my current car is spec'd for a TB application and when I told Circle D that I would just foot brake it in the interim and they told me it wouldn't work very well, and that foot braking would require a different converter.

 

I already have a custom spec PTC converter for my app and they were specifically told foot brake. I have even sent it in once to have it restalled based on my data. It didn't change anything about loading the suspensions while staging.

 

Depends on the type of rear suspension. The Turbo buick days we used pinion snubbers and run them full length at the drag strip to stop it from squatting. That and air bags in the pass rear spring with adjustable shocks and stiffer springs.

The IRS setups you usually ditch the factory dog bone camber bar and put an adjustable one in its place to add a bunch positive camber. Then stiffen up the springs and shocks to the point they were almost ridged. That way when it launched it would squat minimally without the massive amount of neg camber.

 

That's ok, good to see the conversations here. Facebook groups are terrible for this sort of thing and a huge step backwards from forums imho.


I appreciate everybody's input. I do realize 90% of the problem lies in troubleshooting, tuning and torque converter. It may even spool better now that the exhaust is unplugged.

This thread is just getting some info on various camshafts to see how good (or bad) they work. Cam, intake manifold, heads etc are like the last 10%. I'm going to have this car for a good while so looking forward to future tweaking.

 

Cool.
I don’t think you have mentioned what car you have?

Mine is a Nova. It’s essentially a licensed and insured street driven drag car. The word “comfort” isn’t part of the equation. 😊

 

Mine is a 2000 TA, still has AC, full interior and a stereo. Its even on all seasons for now. Its just a nice day daily driver. 99% street, 1% test and tunes. I'd like to make 700whp with good response. Definitely not too much to ask these days. Lol

 

Ah so with driver your TA is maybe 3600-3800 that should be factored in.

Of the camshafts you linked I personally wouldn't do any of them. If I was getting a shelf cam I'd go BTR. If I was going custom I'd go Baker Engineering. Half of the companies you listed are resellers.

But I'm not sure you have 'maxed' out the cam yet.

 

Oh heck no, its only made 550whp so far. The car is slow to spool, making NA power to well above 4k rpms with a 7875 .96ar, that ain't right. Its a boost leak, ebc settings, and/or tune. Gotta figure that out first.

 

Here's a comparison of horsepower, 66chevelle_02ss vs my car, two different dynos and different transmissions but 180whp difference at 4k rpm? Mine is down all that power in the yellow. Something is wrong with my car!

66chevelle_02ss ------mine
5.3 --------------------------- 5.3
VS 7875 .96ar ---------- VS 7875 .96ar
Cam 220/23x ----------- 222/227
Trick flow heads ------ cnc 243
Fast 102/92mm tb --- LS6/stock tb
T56 --------------------------- 4L80E
3.54 gears ---------------- 3.25 gears
Cast manifolds --------- cast manifolds
12psi ------------------------ 13psi

 

Yeah fit all first. Partner with a good tuner who has a great reputation for your combo. What ECU?