Would you...

DorianL

DorianL

solid fixture here in the forum
Staff member
...uptick boost?

Right now at 7 PSI I am getting the below and run 12.30 at 110 with dismal launch traction.

sc004d9a39.jpg


I am reasonably confident the trans can take more abuse. The rearend is an 8.5 with Richmond gears and a lockright auto locker. The driveshaft is stock.

Would you uptick boost? Or too much of a good thing?
 
Why make the traction problem worse with more boost ? Why not do something about about the traction first ?
 
with that type of power curve your certainly not in need of more hp, what you need is much better traction, and suspension mods
with a decent set of tires and a differential like a dana 60, or ford 9" that can take some of that engine torque without shredding in the process, set up correctly with about 3.90 rear gears and slicks the car should easily reach the very low 11 second or high 10 second range, drop a bit of weight, add the decent rear differential slicks and suspension mods and mid 10 second passes should be very easy

play with the calculators and assume you have decent traction,

http://www.dragtimes.com/horsepower-et- ... r+Estimate

http://www.wallaceracing.com/et-hp-mph.php

http://dazed.home.bresnan.net/narrowinga9.html

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viewtopic.php?f=71&t=5083

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viewtopic.php?f=71&t=2186
 
Thanks fellas! I know ;)

I needed some sense talked into me.

For the moment I have stiffer fron coils with QA1 adjustable shocks in front.

Rear: boxed lowers, stock coils and gas-a-just shocks.

Polyurethane all around.

I have a large front and rear sways. Front to be removed for races.

Tires are 325/50R15s BFG Drag radials.

Not sure what else to do... I once read offsetting the rear upper control arms to better pin the rear down during launch...
 
DORIANL
I posted this question over on a different site to get a bit of info that I might otherwise overlook, I always find that I learn more if I play DUMB and ask questions, its always best to get info from several sources even if you THINK you know all the answers because you ALWAYS find that several points of view tend to bring you more incite and several bit of info that you might otherwise have overlooked
, any and all info is very welcome, Ive always said its better to act a bit dumb , ask a few questions,and listen to those who may have more info on any subject, because its always true that if you get a half dozen experienced car guys together at least one or two know a few thinks you forgot, overlooked or just never thought about!


"what are the minimum rear suspension mods to be done to a 1973 Malibu to significantly increase traction and durability "
now Ive got a 9" ford differential that I can weld custom brackets too and install with a drive shaft safety loop, drive shaft etc. to replace the crappy 10 bolt rear, but Ive got a car here with a real 600hp supercharged sbc that needs a much stronger rear suspension ,that I can use with slicks and since I mostly build camaros novas and corvettes, which im more familiar with, and my last car with this type suspension was back in the mid 1970s (a 1965 GTO) IM sure theres been improvements over the air shocks and adjustable length link bars that car had, Im open for suggestions, from you gentlemen who normally deal with this type rear suspension,
I know the 10 bolt rears a waste of time so thats going no mater what but suggestions on replacement upper and lower links or other mods are welcome.
yes I could go nuts and just install a custom 4 link, but Im looking at all options

lots of clear pictures and part numbers and vendor info would be helpful "


heres some info I got from TOM MOBLEY

http://www.autoanything.com/suspension- ... 7A0A0.aspx

http://www.hrpartsandstuff.com/

http://dazed.home.bresnan.net/narrowinga9.html

http://www.crankshaftcoalition.com/wiki ... _a_rearend

http://www.bhjproducts.com/bhj_content/ ... ng/dnk.php

http://www.umiperformance.com/catalog/i ... cPath=2_32


keeping the rear ride height low will help a lot. IMO the Edelbrock hop-stop bars are the most direct method of improving the rear geometery. If you're welding ears on the top of the housing you can make them taller. 1.5" - 2".

There's also brackets that lower the rear mounting part of the lower arms, they work too.

you'll need the adjustable uppers to compensate for the raised mounting points and adjust the pinion angle. The lowers can be boxed or buy aftermarket. They're really not a source of problems. Either of these can be bought from a dozen different vendors, I'd recommend UMI as they regularly participate here, help out with issues. Even issues with other vendors parts.

Then, after all that, you'll want the HR Parts-n-Stuff anti-roll bar or similar. You'll want the one that looks similar to a front sway bay, not the one that's like factory, bolted between the lower arms. doesn't seem to matter if it's bolt on or weld on.

There's guys running deep into the 9's with a setup like this.
 
Yes, I always wanted those anti-hop bars but I do not think they exist for 1973 Chevelles. 'will look around. Methinks that the 8.5 will eventually have to go.

I seem to recall a company called Herbert something-or-other sold some. It seem such parts always skip my generation of Chevelle/Malibu.

Could those brackets be modified to work with what I got?

Dick Miller!!!! That's who it was...

http://dickmillerracing.com/store/page10.html

I have his book somewhere...
 
This is quickly turning into a drivetrain thread. I discarded the idea of upticking boost.

Better traction seems to be the way - still those relocation brackets + sticky tires on my 8.5 Hmmmmm.
 
that 10 bolt rear differential will more than likely have about 10 times the usual life expectancy of a snowflake in July in Arizona, once you get the suspension to hook up and big sticky slicks on the car with that power curve , on my first Pontiac fire-bird, I could destroy street tires very easily with the 421 engine I installed in it after the stock 400 had bearing problems, neither the 400 nor the 421 busted the 10 bolt rear with street tires as they spin easily and act like a fuse to dissipate the shock loads, but after only about 4 hard launches with slicks on the car the rear differential started clicking, and within a couple day it was toast!

viewtopic.php?f=71&t=237
 
So yer saying I shpould not bother trying to make this stick with the 8.5?
 
Right - I made a couple of calls here...

I probably can find a DANA 60 - 1985 Suburban that I know might have one.

The problem is that this is a street car that needs to pass tech inspection every year. If I do a good job modifying that DANA 60 to fit + clean up and paint... the tech inspection won't catch it.

If I have to modify the car in anyway that is visible... cutting and welding wheel wells... it won't fly.

In other words, I gotta research this and figure out if I can get away with simply swapping in a modified DANA 60 else, this is dead in the water.

(Also my opportunity to learn how to weld :D )
 
DorianL said:
So yer saying I should not bother trying to make this stick with the 8.5?
Click to expand...

no IM saying if you want the car running low 11 second times or better your stock 10 bolt is unlikely to be a long term companion in your cars drive train, simply because it was never designed to handle 600 ft lbs of torque,on a steady basis and that a stronger rear differential is going to be a much more durable part of the drive train.
If you do the research you'll find that theres stronger gears and axles etc. that you can use and that theres a few cars running fast times using a built 10 bolt rear, but if you do a good deal of research you'll also fine train car loads of shredded 10 bolt differentials that were used in high hp cars.
the ford 9" is a decent option, the first thing youll want to do is measure the length of your current differential

Rear Axle Specs
Here's a case for bigger is better, at least in terms of strength. Larger-diameter ring gears, axles, and pinion shafts all constitute stronger components. Basically, the greater the spline count, the larger the shaft minor diameter, which is the diameter of the shaft at the base of the splines.

WEIGHT
(POUNDS)
REAR AXLE COMPLETE
ASSEMBLY
W/O BRAKES COMPLETE
ASSEMBLY
W/BRAKES
12-bolt 171 210
Strange S60 191 230
Currie 9-inch 174 238

Read more: http://carcraft.automotive.com/94996/cc ... z1UlC1jniF


REAREND RING
GEAR
DIAMETER PINION
SHAFT
DIAMETER PINION
SPLINES AXLE
SPLINES
OE AXLE
SPLINES
PERFORMANCE
Dana 60 9.75 1.625 29 35 35
Ford 9-inch 9.0 1.313 28 28/31 31, 35
GM 12-bolt 8.875 1.625 30 30 30, 33
Ford 8.8 8.80 1.625 28 28/31 31, 33

Read more: http://carcraft.automotive.com/94996/cc ... z1UlBIfcBB

http://dazed.home.bresnan.net/narrowinga9.html

http://www.crankshaftcoalition.com/wiki ... _a_rearend

http://www.bhjproducts.com/bhj_content/ ... ng/dnk.php

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don,t forget the stock rear differential may need to be upgraded if you have a significant power increase.
chevelledana.jpg

chevelledana1.jpg

http://www.summitracing.com/search/Prod ... ssemblies/
 
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