many have asked...objective HTH truckarm handling/ride report [Archive] - Chevelle Tech

: many have asked...objective HTH truckarm handling/ride report


69boo307
Mar 9th, 04, 8:23 AM
I got my car aligned yesterday, got some mufflers, and was able to do a little 'real' driving with it now that the brakes are getting broken in well and I've got most of the bugs worked out of the car.
I have a fairly aggressive alignment, with -.7 camber and +4.5 caster. Yes it wants to track grooves on the highway a little, with the big tires, but in corners it more than makes up for it smile.gif .
Other points that might affect it: I have stock steering box(slow and sucky), and new poly body bushings and trans mount(vibration city).

I'll do alot of comparing with my 2002 Z28 camaro, which is kind of the 'benchmark' I was wanting. My goal was for the chevelle to outperform it. I think it's very close, if not superior. I know it will stop faster than the camaro.

General:
typical A-body body roll, totally gone. It's noiser than stock, but feels so much more secure. I can actually drive the car, instead of feeling like I'm captain-ing a sailboat.
I'm now fearless to take it out on the highway, which was not the case before. the rear suspension is noiser than stock. the panhard rod has spherical aircraft-style bearings, which can make some racket when you hit a big bump. that just goes along with the territory though. Poly and spherical bushings are gonna be more noisy and transfer more vibration.

Highway ride:
The HTH supplied springs provide a slightly stiffer ride than my camaro. It is very well 'grounded' to the road and has a tight feel. Lane changes are now a pleasure instead of a scary experience. The poly body bushings transfer more road vibration to the cabin...but I was expecting that ahead of time. Not good if you want a nice quiet ride, good if you want to feel the road.
I feel that the rear springs may need some adjustment on the spring jacks (comes with the HTH kit). I have the rear height set a bit lower than stock, and the springs feel just a hair too stiff, if that makes sense. I'd like a slightly more 'damped' feel in the rear, it's a little on the lively side. I'll do some tweaking with the springs jacks and see if I can adjust the rear. My camaro has fairly stiff rear springs, but it still feels well 'damped'. don't know of a better way to describe that, hopefully it makes sense.
The Carrera shocks that came with the HTH kit are top-notch. They remind me of Bilsteins. Not the best for your cushy luxury type ride, but excellent performance shocks that have very fast response to bumps and irregularities in the road.

Curves:
Last night I took my car out a little deserted country road that I frequently use to 'test' new handling mods on my camaros I've owned, as well as the vette I owned. It has some pretty good curves and rolls up and down hills in the process.
Pre-HTH, I couldn't have managed more than 45mph out this road. In the camaro, I can comfortably take it at 65mph without drama. I still didn't want to push the chevelle too much, as I'm still breaking it in, but I took this same stretch of road at 60-65mph and the car didn't flinch. It has considerably more in it. Even with the crappy old steering box, the car tracks smoothly around the curves with less body roll than my '02 Z28. I never once felt any understeer, or felt the car pushing. It tracks properly, and goes where you tell it to go.
It really does not feel like a 35 year old a-body, the handling is very comparable to that of a new f-body. With equal horsepower, the chevelle would be all that my Z28 could handle. The little 307 doesn't exactly allow you to shoot out of the curves tho. smile.gif
The only negative point I found thus far, again the rear seems slightly too lively, if you hit a bump mid-curve, it'll want to kick out a little. My camaro does the same thing, but to a lesser extent. I think this can be remedied by getting the rear spring jacks set better. Even as it stands, however, there is no comparison to the original setup. If I'd attempted to drive out that road at 65mph with my original suspension, I'd have been wrapped around a tree.

Braking: I do not have the HTH brakes, I have C5 vette brakes with Hydroboost. These are nothing short of amazing! I must say I am more impressed with the brakes, than the suspension setup. good braking is simply not something you associate with an old muscle car...This setup just rules though! Without a doubt it will stop at least as fast, probably faster, than my '02 Z28. the chevelle weighs a couple hundred pounds more, but I also have the huge C5 calipers, and 13" rotors. the hydroboost, though not fully broken in yet, has a nice feel to it. The pedal is fairly soft at the top, so you can tap the brakes without abrupt motion...but as you lay into it they begin to clamp down HARD. I havn't explored the limits of this setup yet, but thus far I am absolutely thrilled with it!

Hopefully this is helpful to those considering the setup. If you want handling, and you don't mind a little noise and feeling the road, it's awsome. If you want a cadillac-type ride, you might want to stick with something a little less aggressive.

-Brian

72SSAbody
Mar 9th, 04, 8:44 AM
Originally posted by 69boo307:
Braking: I do not have the HTH brakes, I have C5 vette brakes with Hydroboost. These are nothing short of amazing!

-Brian Brian,
I received my CNC'ed C5 brackets today. I'll be sending you out a pair to use per our discussion. graemlins/thumbsup.gif

Thanks for updating us.

Joe

TronDD
Mar 9th, 04, 9:09 AM
What did you start with? Stock 30+ year old rubber bushings? Open control arms? What have you got on it for sway bars?

Tim.

69boo307
Mar 9th, 04, 9:11 AM
I started with the original stock suspension and rotted old rubber bushings. I can't really base a comparison on a 'new' stock chevelle suspension...thus I based it on my camaro instead. Anything is better than what I had on there to start with. My goal was for it to at least equal my '02 camaro, and I think it's there with the exception of the anemic 307 and more noise/vibration than the camaro.

I'm using the stock original front swaybar (cleaned up and powdercoated tho), no rear swaybar.

69boo307
Mar 9th, 04, 9:26 AM
One other important note about the HTH setup, you cannot use a 'TA' or 'DTS' type aluminum diff cover with it! it hits the panhard crossmember. Only a stock diff cover will clear everything. The DTS cover adds about 1 1/2 inches behind the diff. I found this out the hard way...apparently HTH has never installed this system on a car with a DTS style cover.

cperrell
Mar 9th, 04, 2:01 PM
The only negative point I found thus far, again the rear seems slightly too lively, if you hit a bump mid-curve, it'll want to kick out a little. I had this same problem with a couple 3rd gen firebirds I owned a while back (82 TA and 87 formula 350). I always suspected it was because of the panard rod, since it will cause the rear to move sideways a little as it arcs up. I was hoping the HTH kit would have been able to fix this trait. I guess you can minimize, but not totally eliminate it.

The NASCAR cars probably don't have near the suspension travel that road cars do, so it is probably not a problem for them.

Let us know if you have any luck tuning this out.

Also, were you able to get the exhaust to fit out the back or did you have to go out the side?

69boo307
Mar 9th, 04, 2:57 PM
I just have bullet mufflers and exhaust dumps in front of the axle. Loud, but sounds good smile.gif

sinned
Mar 9th, 04, 10:55 PM
Brian, which bullets do you have. Are they the dynomax race bullets. I was also wondering how they routed around the rear trailing arms and crossmember for the arms.

69boo307
Mar 10th, 04, 7:31 AM
Dennis, I think they're dynomax, but I'm not certain, I just asked for something cheap smile.gif . I will replace the old 307 as soon as I can build another, so I didn't want to spend much on an exhaust system, as my new motor would surely have headers and need bigger pipes.

mine actually dumps out just past the HTH crossmember where the truckarms attach, it is not routed past the truckarms at all. I have seen a camaro with their kit, in pics on their website, with the exhaust routed all the way back over the axle. Every chevelle photo I've seen though with the HTH kit, the exhaust turns outward just past the crossmember, and stays 'outside' of the truckarms, exiting to the side somewhere. Mine kind of exits to the side, I had them turn the pipe out a bit, to help with the cabin noise, but I don't have it visibly sticking out beside the car.
I'll try to post a pic tonight, all the pics I posted in bench racing were pre-muffler smile.gif

Concerning another topic, I lowered my rear spring screw jacks a little less than 1/2" on each side, raising the car about that much. This seems to have improved the rear end feel a bit, and also gives the car a better stance. It had the stock 'sagging rearend' stance before, but I hadn't really messed with the adjustable rear height much. Note, I didn't actually 'raise' the rear, at least above stock height. It probably still sits close to an inch lower than stock in the rear. I'm gonna have to play around with the rear settings to try and find a 'sweet spot'.

I drove it to work today, and did a little 'autocross' in the parking lot (I get in before most people, our back lot is always empty). Although it sucks doing that while sitting on a vinyl bench seat, I'm still very happy with the results of this whole project.

kip
Mar 10th, 04, 8:25 AM
brian,

how much clearance is there between the V40's and the C5 caliper ? I have the C5 setup for my '69 camaro and am searching for rims.

thanks,
kip

69boo307
Mar 10th, 04, 8:43 AM
Very little. the clear fine, diameter wise, but I'm having to run an 1/8" spacer to clear the 'face' of the caliper. The Corvette logo was hitting the back of the spokes. The spokes on the V40 are pretty thick, as opposed to C5 vette wheels which have thin spokes.

I also had a very good shop install my tires, they used the 'sticky' weights, and positioned them so they wouldn't cause clearance issues with the calipers.

kip
Mar 10th, 04, 10:58 AM
the torque thrust II's are the same way i've found out. need to run a small spacer. apparently the C5 caliper/C4 rotor 'hybrid' set up yields about a 1/2" more clearance.
thanks for the info....

kip

72SSAbody
Mar 10th, 04, 11:31 AM
Originally posted by kip:
the torque thrust II's are the same way i've found out. need to run a small spacer. apparently the C5 caliper/C4 rotor 'hybrid' set up yields about a 1/2" more clearance.
thanks for the info....

kip The "hat" height of the C4/Cobra 13" rotor is greater than the C5 rotor.

kip,
I think I know who you are speaking of with the brackets for the hybrid swap. Be careful running that bracket as it is a dangerous design and needs some serious improvement for the cyclic loading it goes through.

Joe

kip
Mar 10th, 04, 12:04 PM
brian, sorry to bring this post a little off topic.
joe,
i dont have the hybrid setup, i have the C5 stuff. was just looking into a rim that clears without a spacer. but i will most likely end up running a small spacer, no big deal.

kip

69boo307
Mar 10th, 04, 12:10 PM
If you want old-school looking rims, you'll probalby need the spacers with the C5 calipers. I'm sure you could get more contemporary looking billet style rims that would clear on their own.

K_Janisch
Mar 10th, 04, 1:26 PM
Brian
Great update and great website. I appreciate you posting the $$$$ on your site - sure does help with planning. graemlins/thumbsup.gif
Kurt

69boo307
Mar 10th, 04, 1:44 PM
Unfortunately I need to update the expense sheet... and add another grand or so worth of stuff.

69boo307
Mar 10th, 04, 5:56 PM
here's one showing the exhaust

http://home.nc.rr.com/brengl/images/chevelle3.JPG