my dad and i used to race his 77 vette with a 475 and nitrous. it went 8.02 in 1000 ft track (9.40's quarter) with the stock rear end. we went to a 9" ford rear shortly after just to be safe. you might want to get the good half shafts, i hear they hurt when they come thru the seat and into your ***!

 

I've been making numerous passes in the mid to low 12's for the last year and or so on ET streets in my 90 automatic without problems. (knock on wood)

This better not jynx me.

Sorry for your mis-fortune. If it makes you feel any better, I just got a high $ ticket for a 70mph wheelie on my crotch rocket. I thought the road was deserted. It was except for one well hidden constable. I could have probably ran and easily got away but I'm just a thrill seeking idiot. Not a dumba$$.

You gotta pay to play.

 

This needs to be said:

M/T ET Street Radials ARE DRAG RADIALS, not to be confused with M/T ET Streets.

I've dumped my clutch on them from 4500rpm over 100 times so far without a hitch, not to mention a burnout before each one of those. Sounds like a freak incident to me.

 

I guess I hadn't thought of that, sounds pretty painful. Quite the visual too!

 

Just don't do my buddy did on his ZX-9R, went to pass a Suzuki Samari on the right as it was turning to the left. He went for the pass at about 80 and the Suzuki darted to the right hand curb at the last minute. Bad things is all I have to say. Ride safe! Better yet, stick to the 'vette.

 

I've had that same thought about it being a freak incident, but I still have a pile of broken parts. And the Denny's Nitrous Ready Half Shafts are less money than the OEM shafts. Your clarification of what type of tires they are is absolutely correct, they are the radials.

 

The problem with replacing the 1/2 shafts with aftermarket ones is the weak spot will just move to a more expensive location.

The problem with manuals and sticky tires is the same thing you come up against with a fastener that is stuck and you get our your trusty mallet and old wrench. You put the wrench on the fastener and then take the hammer and wack it. Well this is the same thing that your rear is seeing when you dump the clutch, its referred to as a shock load. The actual "load" is not as much as you hanging on the fastener with your all your weight, but rather its an abrupt delivery of the force. This type of loading is very difficult to sustain.

Furthermore the next thing to go in your rear is the front portion of the differential housing itself. The natural tendency of ANY rear is for the pinion gear to want to climb the ring gear. This causes the pinion yoke side (front of the housing) to want to raise upward. But as you all know we have a c-beam to help stop this. The problem is what you develop there is a HUGE stress riser at the snout of the housing. This is why you see pictures of guys with the snoutes of the housings ripped off.

With an auto you can load this up; and avoid the "whip" you get when you dump the clutch. This lessens this effect and keep you from having housing problems.

I have spend uncountable hours under these cars looking at the things that happen on a launch and know for a fact my car would not last 1 run with manual launch - but yet its made several hundred probably on the stock setup behind a 5k stall converter - that loads in a more uniform (non-shock method).

I will be out working on mine tonight and have an idea that might help some of you guys out with making these more bullet proof for manuals. And might even make the rear a little stiff too for us Auto guys...

Remember EVERY ounce of movement in a car that is being moved other than the wheels is wasted and WILL slow you down. This is why all out drag cars have FIXED motors, solid trans mounts, and solid bushings EVERYWHERE there can be potential motion....even on the body mounts...Its not because things are stronger, its because there is movement that is being wasted.

 

I have the same tires as you do and a McLeod twin disk clutch, so I know I am hitting the tires harder than you are. After I added the ET street radials, I broke a spindle on the 5th or 6th pass with the tires. I replaced the spindle, and broke it again in 4 passes.

Despite what the majority of the forum says, I think it is possible to get a rear to live with a manual transmission. tpi421vette is using a 6 speed and made 100's of passes in the 1.5-1.6 sixty foot range before he broke the D44 case and Jeb Burnett probably hits the tires harder than anyone else on Earth in a C4 with a stick, and his car holds together.

In my opinion, you can make the rear live, it's just more difficult with a stick than an auto. Here's a couple things you can do:

-Install solid or poly bushings in the batwing. Any flex is bad.
-You can box in the stock batwing.
-At the track, tighten the monoleaf nuts about another 1/2 and inch. That should tilt the rear tires inward, and when you launch it should flat the tire to the track and help you hook. When you are dropping the clutch at 4k+ you are probably wheel hopping some. Even if you can't feel it, it's probably doing it. Having the tire hit flat, with help with the hop, which will help keep the rear in 1 piece.
-A lighter car
-Steeper gears will reduce the load on the rear
-You could slip the clutch some, but that will kill the stocker in a hurry
-Make sure the rear alignment is on
-bigger/stigger rear sway bar
-an adjustable heim link on the right side of the rear sway bar. If you can pre-load the right rear, that should help you hook. The dead hook is much easier on parts than a wheel hop scenario.

You might also try airing the ET radials up some, so they spin a bit. 30 PSI or so. They should still out hook a street tire, but the little bit of spin should help the rear.

What I found with my car, was that I could feather the throttle and the clutch on street tires and come up with 1.9 sixty foot times. To get a 1.9 on the ET radials, I had to use your method of running it to 4500+ and dropping the clutch. The tires changed my ET by zero, all I gained from them was a bunch of abuse on the rear end and transmission.

I have some ideas on how to better utilize the tires, but I won't be able to try anything until I get my rear put back together again.

I really think, especially with our modest power levels, that we can make the rears live. tpi421vette was hitting the tires with 700+ RWHP for seasons at a stretch without breaking anything, so I know it can be done. Don't give up man, we/you can figure this out. Replace the half shaft and got back to a nitto or something for the time being.

 

Yes, this is why I always used street tires, not even DR's. I am not in to repair costs due to drag racing, just want a little fun once in a while.

 

Neat

tpi421 installed a solid rear in his car....why? Because of everything I said above...the rears in these cars will NOT hold up to any sorta power with a manual and sticky tires. Jeb is looking into chromoly 1/2 shafts and solid u-joint caps; and a completely redesigned c-beam to counteract the "whip" I was describing....ask him what his c-beam looked like the last time he had it out!

To air up the tires and let is spin is counter productive....that is going to induce spin and possible wheel shake or chatter that will break things like spindles etc even quicker. I know I can tell when mine is going to break something because it chatters leaving the line and again you have the "air impact" effect I described before...believe it or not, dead hookin it would be the best bet....as I said before as long as mine dead hooks it feels silk smooth on the launches and has been holding up to 1.37 60' times.

At the end of the day, He has to decide what is he looking for...if its simply to bracket race and not go fast; the simplest option would be to have a tune put together with no timing in it to kill the power and just race. But if its to continue going quicker while also bracket racing, there are few options.

I personally log at least 100+ runs a year on mine, which is probably more than most - my failures are not very frequent(knock on wood), which leads me to believe my advice is sound in that an auto is the main factor to make these cars live; since the power I am making surely doesn't help matters and is probably working against me in every way possible.

The way I look at it is pretty simple...a conversion to an auto is about 2000 dollars; one major failure of the rear center section is going to cost you at least that amount to replace, and worst of all you are setting at the end with the same thing you had before.

And the solid rear conversion; for the costs associated I have not been able to justify the expense...its over 6k to do it right and I can replace a LOT of u-joints and the not so frequent 1/2 shaft for much less....and I have only seen 1 car really gain a ton from the solid axle conversion to weight in the factor of performance gains....awaiting insanity to get his out with corkvettes old motor; which should be pretty comparable to what I am running...he got out a few times and got mid 1.4 60' times; which are a little less than what I am running. Hopefully with some fine tuning they can get it down in the mid 1.3s which might sway my thoughts on the expense.....we'll all have to wait and see.

 

I thank all of you for your help, I consider everything that has been as valuable information. I realize that there is more than one right answer, it just depends on what your experience has been. My car will stay basically stock except for the free mods, I'll be ecstatic if the car ever sees 13.5. It may never see that number, but I'll have fun trying. All I'm trying to do is have fun reliably, if I have to change my driving style then I'll do it. I'm willing to spend some money to beef things up a bit, but I don't want to spend a fortune to do it. It's obvious that I bought more tire than I needed, should have asked you very nice folks first. Thanks again!

Adam.

 

I agree 100% with what Jesse is saying, and tpi421 did go solid axle after he broke his D44. He made lots and lots of runs with some insane power on the indy though. That was my point I guess, that he made lots of runs with the indy and very few problems until he broke the case. The OP and myself are making literally 1/2 the power of tpi421, and somehow Jim made his indy live through 100's of runs. I've seen Jim's car come out wheels up, and lift the drivers side again when he shifted into second. I saw it pull at least one tire on the launch every race day for almost 2 years. Sure, he broke parts here and there, but it wasn't an everyday occurrence. In fact, the only time he broke anything was after he switched to the twin disk clutch. With the single disk, he made lots of passes with out a single failure.

I don't know much about Burnett's car, other than what he told me on the phone, and that it lays down sick numbers for a manual shift car.

I'm probably being hard headed, and I am probably wrong, but I just refuse to accept that a stock car with sticky tires will grenade the rear and there is nothing you can do about it except swap to an auto. I keep using Jim's car as an example, but there just aren't many big power, big tire, stick shift C4 drag racers out there. Jim made a ton of passes with 500+ RWTQ and never broke ANYTHING until he put the dual disk clutch in the car. The single disk obviously hit the tires softer than the dual, but I am sure it hit a Hell of a lot harder than the stock clutch the original poster is using.

I love drag racing, and I love shifting. There's just something about rowing your own that appeals to me. I'll never put an auto in my car, and I'll never stop drag racing it, so I am forced to find a solution. Or just keep buying parts.

At one time, cutting 1.3's with the indy and an 11 inch tire was impossible. You're doing it now Jesse. I think it's the same thing with the stick shift and the rear, it's not impossible, just difficult. It also hurts that there are so few stick shift C4's out there, and even fewer are drag raced, even fewer still put power or tire to them. Everyone runs an auto. It's going to take a ton of time, and some very careful set-up and component selection, (just like your car) but I think it can be done.

I understand that you think it's impossible, and that you think I am chasing my tail, but it would be awesome if you contributed more than, "Convert to an auto, or you're screwed." You have an immense knowledge of how the indy reacts under hard launching, maybe you could help us stick shift guys come up with some kind of solution, rather than just calling us dumb for even trying it with a stick instead of an auto.

You mentioned the nose of the D44 wanting to point skyward. Would some kind of triangulated brace help that? What about adding a cross member to the transmission? What about solid bat wing bushings? There has got to be answers man! Help us out!

 

For you stickshift bashers.

Try an auto on a road course. I saw a C5 at a corvette cleveland high-speed event at Nelson Ledges that unwantingly downshifted as the driver applied throttle coming out of a corner. He crashed and came into the pits with parts missing.

For this reason I prefer a stick. I realize I wont be able to run with the big dogs at the drags but I prefer the versatility. Plus, I can spray nitrous against those ****'s. My nitrous doesnt engage until 3600 RPM so I can make a safe launch and then annhilate from behind.

Different strokes different folks.

 

I'm dealing with tired equipment, 16 year old car, 117K miles and it lived a semi-charmed life before I got my grimy mits on it. Autos don't work so well in autocross or time trial, so I'll keep my stick. May be a stocker shouldn't be breaking rear-end parts, but mine did.

 

I’m not trying to hijack the thread here... it fits the topic.

I ask, how was it possible for Bowtye8 to launch a 383/6speed at 4000 rpm, pull consistant 1.6 to 1.5 sixty foots, run 11’s and not have any issues other than a spider gear. After that was beefed, he had no other issues.

Go to his web-page and check out his videos. That is one impressive car.
http://bowtye8.tzo.com/

 

That's my point I suppose. That some people seem to be able to do it, while others can't. What are the guys who are making it work doing differently than us that aren't?

 

First let me point out that NOBODY is bashing sticks guys....the points we are trying to share are just those that we have seen across years of dealing with these cars.

Another thing that I clearly pointed out is there are compromises that are possible to make the stick cars live, but as mentioned they are compromises. One specific ones is the mention of single vs dual disk clutches....when you start making the power you describe above; the need for a dual disk is because the single is slipping, softening the launch and ultimately hurting your performance. Not something that I am sure tpi 421 or anyone putting major money into their setup wants to live with....its like building a 700hp motor and then tuning it to only output 500hp. Not sure why someone would go the extra length to only cut themselves short in the end.

Their are serious limitations to these rear setups....again last night I spent over 7 hours setting up my gears to ensure they were perfectly the way I have set them to survive....this meant assembling and disassembling the unit 8 times.....

Neat, I apploud your determination that is what is needed to come to a solution for the stick usage....I will never tell anyone that something can't be done.....god knows I have been told that a zillion times through my journey with my car...which just fuels me more to prove it can me. My advice through this thread was not to deter, bash, or sway people's opinions of stick drag cars; it was simply to point out what I have seen and learned in my quest to run a 1.2 60' time with my car

 

This is the information that I am most interested in. How come somebody that has stick shift car that has made 100 passes with the exact same set-up as I'm running has never had a problem? And I grenaded my car in 5 passes. What did I do wrong and what are they doing right? With the details that I've given above, what's my best course of action?

Adam.

 

[QUOTE=ski_dwn_it]First let me point out that NOBODY is bashing sticks guys....the points we are trying to share are just those that we have seen across years of dealing with these cars.
Thanks so much Jesse!

 

If you've ever worked on or in an environment where things are repeatedly used until broken and constant replacement is a mainstay you would understand what I'm about to say. For whatever reason I dont know but some identicle parts out last others. They can be made at the same time at the same place with the same materials and used in the same manor and conditions yet some last for months while other only last for moments.

Example: I worked at a heavy duty tractor trailor brake shoe re-lining plant as a kid. We had these rivit machines used to rivit new brake friction material lining onto rebuilt cores. These machines used an anvil to round the rivit off at the end when rapidly compressed. For whatever reason some anvils would last for months and some for only moments.

It's like some had bubbles in the casting. Or perhaps weren't properly handled or treated by the worker at the production plant that day. I dont know. It's just a freak thing sometimes. But under the same exact conditions, some would way out last the others and some would just flat out fail in a heartbeat. For no apparent reason.

I think half shafts and other parts could be the same. It's just the luck of the draw. For some unknown variables, some will last for years under the worst conditions and some will break quickly under little to no unusual stress.

One of those things that make you go hmmmm.