chevelle suspension questions

kychevyman · 09-28-2009, 12:09 PM

I may be posting this in the wrong section. I just wanted the right people to see it. I have a 68 chevelle that I bracket race locally. SBC for power, runs 7.20's 1/8 mile leaving on transbrake. Rear suspension is homemade lower bars, jegster upper adjustable, moroso springs,comp eng shocks, nohop bars and one passenger side airbag at 11 psi. Front is new replacement springs not moroso and comp eng shocks. My problem is the car runs good and hooks when its dark or overcast and below 70 deg. But if the sun is out it blows the tires off and is .05 slow in sixty foot. Will taking the nohops take some bite out of the car or is this the wrong thinking. Pinion angle is about two degs down. What are my options here???

kychevyman · 09-29-2009, 01:07 PM

Lets change this to a simple question. I dont want any great detail. What is the purpose of a set of no hop bars on a stock suspended chevelle. I know what they were for on the street but what purpose do they serve in a dragcar. Thanks.

67ss · 09-30-2009, 06:39 AM

The no hops move the instant center back and down which hits the tire harder on the intial launch initiating body separation which is a good thing on these big heavy chevelles up to a point. Taking them out will take hit out. At 7.20's you are nearing the point where the no hops are hitting the tire too hard but with a small block I don't think you are there yet. I ran them down to 7.1's with my 396 BBC with good results.

And when you say homemade lowers are they mounted in the stock mounting points? Rear of lower bar isn't lowered or anything?

Detail is what you need here. This is likely a whole combo issue not just a no hop bar issue.

What trans, rear gear and converter?

Battery in trunk?

What are your current 60' times? I don't like the moroso springs in the rear. I know what they are designed to do and why Dick Miller goes that route as well but without a good double adjustable shock they are not going to work. I would stick a stock type spring back there. Problem with those moroso springs is they will allow for good initial hit but they are so weak they allow the rear axle to rebound and unload the tire.

I don't like the comp three way shocks. A good shock for you front and rear would be Koni SPA1's set on full loose up front and some where around 1 turn or so from full loose on the rear. If car hooks on initial launch then unloads tighten rear shocks up. If car spins on initial hit loosen rear shocks. Fronts will likely just stay on full loose at all times.

How much front end travel do you have with car at rest until front tire just begins to lift off ground? Need at least 6" of travel. Otherwise you are hitting the bump stop before the car can get going and transfer weight to rear tires. This can be accomplished with upper bump stop adjustments and with a different front spring to get the front of the car lower. Get that stock front spring out of there. The front is a good place for a moroso spring or scale the car and call Santhuff for a pair of their front springs. You need a tall light rate front spring to store energy in the srping to help with weight transfer. If the spring lowers car a touch too much call Savitske Classic and Custom in penn. and get a pair of their spring seat spacers in the correct thickness to adjust. Their web address is www.scandc.com. You can talk to them too about the Howe low friction upper ball joints that come with longer studs to raise the upper control arm for better geometry as well as an increase in front travel. Another good option up front is a set of low friction bushings such as global west del-a-lum.

You can look out back all you want but if the front of the car isn't set up correctly you will never get it too work.

Also...what kind of tires are you running?

kychevyman · 09-30-2009, 07:11 AM

Thanks for the post. Alot of good ideas. I'm just starting to run this car some. Ive been junior dragster racing with my son for eight years. As far as lower control arms they are stock location front and rear. Just a 1/2 longer to help pinion angle before upper adjustables were purchased. 400 turbo tranny, 4.88 gear and a 8" converter. I honestly havent dry stalled it or looked at the tach when it leaves. Id guess it goes to about 5500 or so. Battery in the trunk. 16 gallon fuel cell half full. 60 foot is 1.53-1.55 on a decent run. I'll do some checking on the other stuff. Thanks for the help. That gives me something to work with.

09-30-2009, 08:56 AM

I had an adjustable Art Morrison suspension a long time ago and my car did the same thing durring the day. Try taking out 2 degrees of pinion angle. I ran my at 0. With the car at ride height. When the body and tire seperate on a launch with those cars the downword pinion angle increases. In my directions for that suspension they wanted the pinion angle set upward not downward. Hope this helps. Might be all you need to do. Good luck

Quote:

Originally Posted by kychevyman

I may be posting this in the wrong section. I just wanted the right people to see it. I have a 68 chevelle that I bracket race locally. SBC for power, runs 7.20's 1/8 mile leaving on transbrake. Rear suspension is homemade lower bars, jegster upper adjustable, moroso springs,comp eng shocks, nohop bars and one passenger side airbag at 11 psi. Front is new replacement springs not moroso and comp eng shocks. My problem is the car runs good and hooks when its dark or overcast and below 70 deg. But if the sun is out it blows the tires off and is .05 slow in sixty foot. Will taking the nohops take some bite out of the car or is this the wrong thinking. Pinion angle is about two degs down. What are my options here???

kychevyman · 09-30-2009, 09:06 AM

I forgot to add tires are mickey thompson 3056st. 29.5 x 9

mannymen · 09-30-2009, 09:55 AM

talk to 1320 racer at DRR he can best help you with this exact subject.

Bimbo Jones · 09-30-2009, 10:35 AM

Kychevyman I run 7.20's using a t-brake and 9" slicks in my 65 chevelle wagon. The best tool for me is a infrared heat gun to tell the track temp. I'm running a sbc and don't have near the torque of a bbc. when the track gets over 110 degrees I have to lower the luanch rpm from 4200 to 3400 plus add about 150lbs in the rear to get it to hook. As long as you are limited to using 9" slicks you will have this battle using a transbrake. Now my car is deadly as a foot breaker even in the heat. That has a lot to do with hitting an unloaded suspension and those little slicks. I'm wanting to put the stocker motor in the wagon so traction will no longer be an issue. and take my drivetrain and put it into a 79 Malibu with some big slicks to deal with the slippery tracks in the Texas heat. BTW, I slowed the car down almost two tenths to get it to stick in the heat. Good Luck though.

67ss · 09-30-2009, 10:53 AM

I don't buy the pinion angle post. 2-2.5 degrees down should be sufficient in relation to the trans or you can measure off the damper. If the damper is 3 up then the pinion should be 5 down for a difference of 2. When the pinion climbs the ring gear the pinion angle will go up and your goal is to be parallel with the trans yoke or 0 degrees pinion angle going down track. Pinion angle on these cars has no bearing on traction but more on driveline efficiency. I used to run the hop stops and stock type lowers and never had my pinion angle at 0 or up nor did I see the pinion angle go negative with rear end separation.

I ran that same tire but not the ST. I ran the L8 compound tire. The M5 is a harder compound but if your issues are in the heat that shouldn't be an issue and maybe needed with a transbrake launch to keep from shearing the rubber. Are these mounted on at least 8" rims?

You could kill some of the hit with a gear change to say a 4.33. I know my 396 gave me fits with a 5.13 so I stepped back to a 4.56 and tamed the car down.

Some rear mounted ballast isn't a bad idea as well.

Work on the front end and some of the other incidentals and hopefully you will see some progress.

kychevyman · 09-30-2009, 11:31 AM

They are mounted on 8 inch rims. I've heard of using a 10" rim. Bigger footprint is the only benifit? Can I expect any change from say 50 lbs in the trunk? This weekend I'm gonna see what turning the starting line down and some ballast in the trunk does.

09-28-2009, 12:09 PM	#1
kychevyman Junior Member Join Date: Dec 2006 Posts: 10 Likes: 0 Liked 0 Times in 0 Posts	chevelle suspension questions I may be posting this in the wrong section. I just wanted the right people to see it. I have a 68 chevelle that I bracket race locally. SBC for power, runs 7.20's 1/8 mile leaving on transbrake. Rear suspension is homemade lower bars, jegster upper adjustable, moroso springs,comp eng shocks, nohop bars and one passenger side airbag at 11 psi. Front is new replacement springs not moroso and comp eng shocks. My problem is the car runs good and hooks when its dark or overcast and below 70 deg. But if the sun is out it blows the tires off and is .05 slow in sixty foot. Will taking the nohops take some bite out of the car or is this the wrong thinking. Pinion angle is about two degs down. What are my options here???

09-29-2009, 01:07 PM	#2
kychevyman Junior Member Join Date: Dec 2006 Posts: 10 Likes: 0 Liked 0 Times in 0 Posts	Re: chevelle suspension questions Lets change this to a simple question. I dont want any great detail. What is the purpose of a set of no hop bars on a stock suspended chevelle. I know what they were for on the street but what purpose do they serve in a dragcar. Thanks.

09-30-2009, 06:39 AM	#3
67ss Junior Member Join Date: Jan 2008 Posts: 29 Likes: 0 Liked 0 Times in 0 Posts	Re: chevelle suspension questions The no hops move the instant center back and down which hits the tire harder on the intial launch initiating body separation which is a good thing on these big heavy chevelles up to a point. Taking them out will take hit out. At 7.20's you are nearing the point where the no hops are hitting the tire too hard but with a small block I don't think you are there yet. I ran them down to 7.1's with my 396 BBC with good results. And when you say homemade lowers are they mounted in the stock mounting points? Rear of lower bar isn't lowered or anything? Detail is what you need here. This is likely a whole combo issue not just a no hop bar issue. What trans, rear gear and converter? Battery in trunk? What are your current 60' times? I don't like the moroso springs in the rear. I know what they are designed to do and why Dick Miller goes that route as well but without a good double adjustable shock they are not going to work. I would stick a stock type spring back there. Problem with those moroso springs is they will allow for good initial hit but they are so weak they allow the rear axle to rebound and unload the tire. I don't like the comp three way shocks. A good shock for you front and rear would be Koni SPA1's set on full loose up front and some where around 1 turn or so from full loose on the rear. If car hooks on initial launch then unloads tighten rear shocks up. If car spins on initial hit loosen rear shocks. Fronts will likely just stay on full loose at all times. How much front end travel do you have with car at rest until front tire just begins to lift off ground? Need at least 6" of travel. Otherwise you are hitting the bump stop before the car can get going and transfer weight to rear tires. This can be accomplished with upper bump stop adjustments and with a different front spring to get the front of the car lower. Get that stock front spring out of there. The front is a good place for a moroso spring or scale the car and call Santhuff for a pair of their front springs. You need a tall light rate front spring to store energy in the srping to help with weight transfer. If the spring lowers car a touch too much call Savitske Classic and Custom in penn. and get a pair of their spring seat spacers in the correct thickness to adjust. Their web address is www.scandc.com. You can talk to them too about the Howe low friction upper ball joints that come with longer studs to raise the upper control arm for better geometry as well as an increase in front travel. Another good option up front is a set of low friction bushings such as global west del-a-lum. You can look out back all you want but if the front of the car isn't set up correctly you will never get it too work. Also...what kind of tires are you running? __________________ Chad Harris 67 Chevelle SS http://mysite.verizon.net/harrisracing Last edited by 67ss; 09-30-2009 at 06:47 AM.

09-30-2009, 07:11 AM	#4
kychevyman Junior Member Join Date: Dec 2006 Posts: 10 Likes: 0 Liked 0 Times in 0 Posts	Re: chevelle suspension questions Thanks for the post. Alot of good ideas. I'm just starting to run this car some. Ive been junior dragster racing with my son for eight years. As far as lower control arms they are stock location front and rear. Just a 1/2 longer to help pinion angle before upper adjustables were purchased. 400 turbo tranny, 4.88 gear and a 8" converter. I honestly havent dry stalled it or looked at the tach when it leaves. Id guess it goes to about 5500 or so. Battery in the trunk. 16 gallon fuel cell half full. 60 foot is 1.53-1.55 on a decent run. I'll do some checking on the other stuff. Thanks for the help. That gives me something to work with.

09-30-2009, 09:06 AM	#6
kychevyman Junior Member Join Date: Dec 2006 Posts: 10 Likes: 0 Liked 0 Times in 0 Posts	Re: chevelle suspension questions I forgot to add tires are mickey thompson 3056st. 29.5 x 9

09-30-2009, 09:55 AM	#7
mannymen Senior Member Join Date: Apr 2003 Posts: 728 Likes: 5 Liked 13 Times in 7 Posts	Re: chevelle suspension questions talk to 1320 racer at DRR he can best help you with this exact subject. __________________ N/A

09-30-2009, 10:35 AM	#8
Bimbo Jones Member Join Date: Nov 2008 Posts: 109 Likes: 0 Liked 0 Times in 0 Posts	Re: chevelle suspension questions Kychevyman I run 7.20's using a t-brake and 9" slicks in my 65 chevelle wagon. The best tool for me is a infrared heat gun to tell the track temp. I'm running a sbc and don't have near the torque of a bbc. when the track gets over 110 degrees I have to lower the luanch rpm from 4200 to 3400 plus add about 150lbs in the rear to get it to hook. As long as you are limited to using 9" slicks you will have this battle using a transbrake. Now my car is deadly as a foot breaker even in the heat. That has a lot to do with hitting an unloaded suspension and those little slicks. I'm wanting to put the stocker motor in the wagon so traction will no longer be an issue. and take my drivetrain and put it into a 79 Malibu with some big slicks to deal with the slippery tracks in the Texas heat. BTW, I slowed the car down almost two tenths to get it to stick in the heat. Good Luck though.

09-30-2009, 10:53 AM	#9
67ss Junior Member Join Date: Jan 2008 Posts: 29 Likes: 0 Liked 0 Times in 0 Posts	Re: chevelle suspension questions I don't buy the pinion angle post. 2-2.5 degrees down should be sufficient in relation to the trans or you can measure off the damper. If the damper is 3 up then the pinion should be 5 down for a difference of 2. When the pinion climbs the ring gear the pinion angle will go up and your goal is to be parallel with the trans yoke or 0 degrees pinion angle going down track. Pinion angle on these cars has no bearing on traction but more on driveline efficiency. I used to run the hop stops and stock type lowers and never had my pinion angle at 0 or up nor did I see the pinion angle go negative with rear end separation. I ran that same tire but not the ST. I ran the L8 compound tire. The M5 is a harder compound but if your issues are in the heat that shouldn't be an issue and maybe needed with a transbrake launch to keep from shearing the rubber. Are these mounted on at least 8" rims? You could kill some of the hit with a gear change to say a 4.33. I know my 396 gave me fits with a 5.13 so I stepped back to a 4.56 and tamed the car down. Some rear mounted ballast isn't a bad idea as well. Work on the front end and some of the other incidentals and hopefully you will see some progress. __________________ Chad Harris 67 Chevelle SS http://mysite.verizon.net/harrisracing

09-30-2009, 11:31 AM	#10
kychevyman Junior Member Join Date: Dec 2006 Posts: 10 Likes: 0 Liked 0 Times in 0 Posts	Re: chevelle suspension questions They are mounted on 8 inch rims. I've heard of using a 10" rim. Bigger footprint is the only benifit? Can I expect any change from say 50 lbs in the trunk? This weekend I'm gonna see what turning the starting line down and some ballast in the trunk does.