Fox Let's Plot My Rear Suspension...with Track Results!

[RangerJoe]

I am tired of mediocre performances at the strip, so I have decided to put forth a real effort to make my car 60ft. I have read Kevin Slaby's Baseline website numerous times. Here is what we are working with:

-93 GT 3350 lbs race weight
-Estimated 360 rwhp 331
-G-Force T5 with 4.10 gears
-UPR tubular suspension up front, 175lb springs, Strange singles
-Baseline relocated UCA and J&M weight jacket LCA, hemi bushings, Strange singles
-RaceStar wheels with 26x10.5 (8.5 contact) ET Streets
-2 Step with pills from 3100-4900
-Best 60 to date is 1.83 with 3700 launch, spinning and wheel hopping

Ok, that's what I am working with, and I will start another reply with where I am at with the suspension.

Joe
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[RangerJoe]

So I started plotting the suspension using Kevin's Prolaunch calculator.

http://www.baselinesuspensions.com/instant-center.php

The pinion angle was -4 degrees, and I have attached what came out of my initial measurements. This is where the suspension sat when I started.

Joe

 

[RangerJoe]

I raised the car 1/2", which raided the front UCA mount 3/4". I got the following attached change.

Joe

 

[RangerJoe]

Well, I just heard back from Kevin, apparently my plots look off to him. He thinks it is because the car is sitting on blocks for this. While I sort through all this, I need to know what I am shooting for.

@84Ttop @90lxcoupe @Sharad

Anyone have any idea what anti squat and what instant center length I should be shooting for? I know the track will reveal the final combo, but where should I start?

Joe

 

[RangerJoe]

Well, I am enjoying this conversation with myself, lol. Kevin did tell me that an approximate ideal target area is 110% anti squat and 36" IC.

I re-ran my numbers and used the correct graph ,and I got closer numbers. Look at the bottom graph for my current setup.

Joe

 

[TOOLOW91]

I wish i knew more about actually doing this. I am looking forward to learning .

Lights out is at SGMP this weekend so alot of guys are thrashing to get ready maybe the lack of responses

 

[a91what]

What springs you running out back? We have had huge success with stock springs, cut 1 coil...... team z recommended.

 

[RangerJoe]

I wish i knew more about actually doing this. I am looking forward to learning .

Lights out is at SGMP this weekend so alot of guys are thrashing to get ready maybe the lack of responses

Wish I could make it down there, that will be some good racing.

What springs you running out back? We have had huge success with stock springs, cut 1 coil...... team z recommended.

That's exactly what I am running.

Joe

 

[TOOLOW91]

Wish I could make it down there, that will be some good racing.



That's exactly what I am running.

Joe

Joe I have team zs actual spring in mine .

Which is that formula you mentioned but they design the spring at the lower height with the stock spring rate to keep the spring rate constant where as you always run the risk of altering the rate as you cut .


Sent from my iPhone using my fingers while my auto correct makes me seem illiterate

 

[RangerJoe]

I got some good feedback from Kevin last night. He said the last graph I got looked more like it was supposed to. He stated that repeatable results were hard to get on blocks, and the best method was for a skinny person to slide under the car with it on the ground....that's not me.

He also noted that there are so many variances between vehicle mounting points and the exact location people used to measure from, that the suggested target area was only a rough guide. As long as I could measure repeatedly from the same locations, I could use that starting point to work from.

Right now I am at a 166.77 AS and 27.88" IC. By lowering the front end .5", and raising the rear another .25", I think I can get my AS to 120" and my IC to 37". Those are closer to the target area. If it doesn't seem to work, I know what going the other direction will yield and I will work from there.

I am still open to suggestions and feedback from those in the know.

@TOOLOW91, I got these springs before the Team Z's were made, but those may be in the future if I can't get this to work.

Joe

 

[90lxcoupe]

For a stick car, you are going to have to change a few things if you really want it to work. I have tried the team Z relocated uppers and they slowed the car down .05 in the sixty foot, went back to standard uppers and the car was back to normal.

At that time i was plotting the suspension all the time and chasing my tail. My advice, forget those calculators exist, they dont apply to a stock suspension, low horsepower, stick car. The next part will require some parts changes. Go back to a stock style upper control arm, get rid of the weight jacker lower control arms, and go back to stock style with solid bushings there too, that is a must IMO, then you can start looking at tires, are you running the old style ET street or the new ones? The ideal tire would be a 26x10.5" stiff wall slick. Once you do all of that, take the car back to the track, and set the 2step to 5500 and work from there. What clutch are you using?

The stock location stuff works surprisingly well, i am still using all stock location stuff in the rear of the car, and with a setup similar to yours, 390rwhp, i was going consistent 1.45-1.49 sixty foots on high ten second passes. You should be in the 1.50-1.55 range running low 11s when you get it sorted out.

 

[RangerJoe]

@90lxcoupe

Honestly that's not what I wanted to hear. I'm listening everything you say, I know that you know what you're talking about. I just went through buying all these parts at the recommendation of Kevin, I hate to throw it all out the window without trying to make it work.

This car will not see slicks, it will most likely always be on drag radials. The clutch is a single disc dual friction Ram clutch, I don't remember which model but I believe it was rate to 550 or 600 foot pounds of torque.

I bought the ET streets brand new one year ago so I assume they are the newer ones. When you are referring to the solid joints, are you saying go away from the hemi style joints altogether?

I tagged you in this post because I knew you are familiar with the topic. Please don't think I'm not listening to what you say, I have just got to give this a try first, then I may be back here listening to you tell me I told you so.

If I did go back to stock style stuff what do you suggest? Should I just add factory style arms to factory length, what about ride height, where do I get my adjustments from? This is all a learning experience for me, I appreciate all your help, thank you.

Joe

 

[90lxcoupe]

The clutch you have is a good clutch, that is the same one i ran and now have a powergrip HD i will be trying out this season.

The new ET streets are the ET street R's. The old ET street is pretty much useless, and forget about trying to get the car down the track with respectable numbers on a radial. I was in your shoes, stubborn and willing to beat my head against the wall, for 3 seasons i chased a 10 second pass while everyone told me to put a slick on the car but i wanted to do it on a radial. Put slicks on the car and within 3 passes i was a tenth faster to the sixty foot and went 10.67

Stock style adjustable arms with heim joints(solid bushings), is what i suggest, set them to the stock length to start with, then square the rear, then adjust the pinion angle.

Honestly, you are going to spend at least 2 seasons messing with all those adjustable parts just to get where you would be with the stock location stuff. The suspension stuff is best kept simple, you can go a long way with tire pressure, shock settings and driving style(the more aggressive the better).

Not sure if you said you had one or not, but an Anti roll bar should be on the to do list.

 

[RangerJoe]

The clutch you have is a good clutch, that is the same one i ran and now have a powergrip HD i will be trying out this season.

The new ET streets are the ET street R's. The old ET street is pretty much useless, and forget about trying to get the car down the track with respectable numbers on a radial. I was in your shoes, stubborn and willing to beat my head against the wall, for 3 seasons i chased a 10 second pass while everyone told me to put a slick on the car but i wanted to do it on a radial. Put slicks on the car and within 3 passes i was a tenth faster to the sixty foot and went 10.67

Stock style adjustable arms with heim joints(solid bushings), is what i suggest, set them to the stock length to start with, then square the rear, then adjust the pinion angle.

Honestly, you are going to spend at least 2 seasons messing with all those adjustable parts just to get where you would be with the stock location stuff. The suspension stuff is best kept simple, you can go a long way with tire pressure, shock settings and driving style(the more aggressive the better).

Not sure if you said you had one or not, but an Anti roll bar should be on the to do list.

Yeah, they are the old ET Street bias ply, not the new R. Not that I am trying to be stubborn, but the one class that I actually participate in is True Street, so I need a DOT tire, which the R's are I believe.

I am not against running stock style stuff, I just followed the advice of Kevin on parts to buy. I am vested in time and money now, so I need to see if it will work. If it doesn't, then I will have to go in the direction you suggested.

Thanks again.

Joe

 

[A5literMan]

I'm completely useless in the plotting department. To much math and measuring for my brain lol. I always "cheated" and used a bias ply dot legal tire(M&H 26x8.5-15) on my old car. It would 60 in the 1.60's with a nitrous hit(around 325 rwhp according to calculators). The present car only saw a few passes with same power level and borrowed slicks. It ran about the same. Now I've tried with Nitto 555r's(or whatever the part #-name?) and couldn't get any consistency. They never worked with a nitrous hit. Best 60 was a 1.88(no nitrous) and routinely was around 1.95 even 2.00s. I'm watching this thread. I love drag racing topics. I just can't really help with this one. Other than to offer-change the tire to a bias ply and launch the crap out of them.

 

[A5literMan]

The clutch you have is a good clutch, that is the same one i ran and now have a powergrip HD i will be trying out this season.

The new ET streets are the ET street R's. The old ET street is pretty much useless, and forget about trying to get the car down the track with respectable numbers on a radial. I was in your shoes, stubborn and willing to beat my head against the wall, for 3 seasons i chased a 10 second pass while everyone told me to put a slick on the car but i wanted to do it on a radial. Put slicks on the car and within 3 passes i was a tenth faster to the sixty foot and went 10.67

Stock style adjustable arms with heim joints(solid bushings), is what i suggest, set them to the stock length to start with, then square the rear, then adjust the pinion angle.

Honestly, you are going to spend at least 2 seasons messing with all those adjustable parts just to get where you would be with the stock location stuff. The suspension stuff is best kept simple, you can go a long way with tire pressure, shock settings and driving style(the more aggressive the better).

Not sure if you said you had one or not, but an Anti roll bar should be on the to do list.

I have the stock location team z street beast uca,lca,arb bnib in my garage. Just saying....lol.

 

[RangerJoe]

I'm completely useless in the plotting department. To much math and measuring for my brain lol. I always "cheated" and used a bias ply dot legal tire(M&H 26x8.5-15) on my old car. It would 60 in the 1.60's with a nitrous hit(around 325 rwhp according to calculators). The present car only saw a few passes with same power level and borrowed slicks. It ran about the same. Now I've tried with Nitto 555r's(or whatever the part #-name?) and couldn't get any consistency. They never worked with a nitrous hit. Best 60 was a 1.88(no nitrous) and routinely was around 1.95 even 2.00s. I'm watching this thread. I love drag racing topics. I just can't really help with this one. Other than to offer-change the tire to a bias ply and launch the crap out of them.

See, this is why I am led to believe that my stuff is all out of whack. Are the ET Streets not biasply? I hear all sorts of reports on similar 60fts as yours, but I can'T get anywhere close. This makes me think my suspension is all messed up, hence the reason for plotting. Fwiw, the car would never 60 with boxed BBK lowers and UPR adjustable uppers either.

Joe

 

[A5literMan]

Is it sitting square? I'm not informed on how to check/plot everything. I've read a little but you have more information/knowledge than I do at this point. You mentioned you have the radials. Obviously they aren't bias plys. Mickey T's have so many different tire designations I'm not sure which ones you have. Are they radials? I liked the M&H tires a lot. They don't have much tread for any wet weather though. Especially after a few trips to track etc. they don't last long and are a glorified slick. But they worked well for me. I'm going to pm you.

 

[90lxcoupe]

See, this is why I am led to believe that my stuff is all out of whack. Are the ET Streets not biasply? I hear all sorts of reports on similar 60fts as yours, but I can'T get anywhere close. This makes me think my suspension is all messed up, hence the reason for plotting. Fwiw, the car would never 60 with boxed BBK lowers and UPR adjustable uppers either.

Joe

The ET streets are bias ply, but they are old technology, i ran that same tire for a season, with a similar suspension setup to yours currently, and the best i could do was 1.6 sixty foots. The sidewall on those tires are pretty terrible and make it hard to work around. I have heard good things about the new Bias ply ET street R's though. Id like to try a set but i dont know when that will be.

 

[cleanLX]

I ran the old style ET Street bias plys with 100% stock and original suspension, and all of 232hp out of the stock motor and cut consistent low 1.7's. The rear would bounce on take off and unload/load back up as the front extended and then slammed back down (stock shocks/struts). Looked like a quarter operated K-Mart Pony on launch... Always figured with a good shock and strut I could go high 1.6's with stock suspension/motor.
My point? While the old style ET Street is not the best when compared to todays tech, they worked a lot better than 1.8 60 foots.
My engine and suspension are now similar to yours (368hp, Baseline uppers-solid and weight jacker lowers-solid) and I've gone to the new Et Street R bias... hitting the track March 18th, and not going to measure a dang thing. When the suspension was done (tq boxes and such at that time too) 11 years ago it was all set as Kevin prescribed (link lengths, ride height, pinion angle). We shall see.