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tire pressure and shock setting

early2drsedan

early2drsedan

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what type of pressure is a good staring point for at the track with et street drag radials and starting point for rear shocks i 9 way adj. ranchos thanks
 
Start shocks in the middle. 18 psi. Slow motion cell phone video directly from the side at the rear tire. If it spins at the hit, loosen the shock. No spin , tighten. No spin add psi. Don't go below 17psi.
Doug
 
I have et drag slicks on my heavy 73 charger drag car and it seems to like 20 psi. Still wrinkles the sidewalls some but hooks awesome
 
I have my shocks set at 5 (9 way Calvert/Rancho) and ET Street Pro's at 18psi.

Have yet to get a night where prep is good as the street tired cars tend to kill it. 1.65 the other night. Has been as good as 1.54.
 
I think the first thing to know is how much HP and transmission and or transbrake
Doug certainly has the right starting point .
When i footbraked with Rancho shocks i was at #8 or 9 tight and 18 psi
More power i changed shocks , low 11s , and went pro bracket radial at 16.5 psi
Now have 29.5 (30") x10.5 radial and run 19psi

Tex
 
Last edited:
Here is a video from yesterday.
19psi . Tyre contact measurement is 9 5/8" so could drop a little psi to get out to 10" contact .
Dont worry about the Chev



Tex
 
"520 hp 727 3500 stall foot breaking it thanks again f"


what do you hold the revs on the line at? launches great
 
I used to run my ET Street Radials at about 18-1/2 lbs IIRC. I Currently run 28x9 ET drags with tubes @ 16-1/4 lbs. Foot break, running full Calvert setup including shocks (same as ranchos). My best results have come with the shocks full-stiff. My car typically 60’s at 1.58.
 
If I can throw this ? in...
How does the "shock/tire pressure" starting point change when the car has a manual transmission, billet steel stock weight range flywheel and 4.10 Dana 60 in a stock weight 70 440+6 Roadrunner?
Right now I have 315/35/17 Toyo Proxes TQ drag radials, but I am looking at M&H Racemaster 325/45/17s because I think they will fit, and give me some more sidewall.
Thanks!
 
biomedtechguy said:
If I can throw this ? in...
How does the "shock/tire pressure" starting point change when the car has a manual transmission, billet steel stock weight range flywheel and 4.10 Dana 60 in a stock weight 70 440+6 Roadrunner?
Right now I have 315/35/17 Toyo Proxes TQ drag radials, but I am looking at M&H Racemaster 325/45/17s because I think they will fit, and give me some more sidewall.
Thanks!
Click to expand...
Radials and stickshift dont get along

Tex
 
biomedtechguy said:
If I can throw this ? in...
How does the "shock/tire pressure" starting point change when the car has a manual transmission, billet steel stock weight range flywheel and 4.10 Dana 60 in a stock weight 70 440+6 Roadrunner?
Right now I have 315/35/17 Toyo Proxes TQ drag radials, but I am looking at M&H Racemaster 325/45/17s because I think they will fit, and give me some more sidewall.
Thanks!
Click to expand...

Unless you can control the slip on the clutch you need to introduce a little tire spin at the hit (I do 22.5 psi on the drag radials). Also raise your launch RPM to get away from bogging at the line. I use 345/40R17's drag radials and they will bite pretty good with the right amount of heat in them.
 
69sunfireGTX said:
Unless you can control the slip on the clutch you need to introduce a little tire spin at the hit (I do 22.5 psi on the drag radials). Also raise your launch RPM to get away from bogging at the line. I use 345/40R17's drag radials and they will bite pretty good with the right amount of heat in them.
Click to expand...
Thank you!
The best ET and MPH 1320 runs I made came November a year and a half ago.
I ran consistent 13.3xs at 106 mph.
What I had to do was come off the line just above idle around 1,200 RPMs (idle is around 925-950) and as soon as I was rolling, floor it and keep it there (power shifting). I had 3.54 ring and pinion gears at that time, didn't really have a bogging or falling on its face issue, and no wheel spin with the drag radials.
Now with the Passon 5 speed and the .70 5th gear, I went to 4.10 ring and pinion gears which makes that type of launch even easier.
I have a line lock to install now, and that should help traction.
I haven't had a good launch since I installed those 4.10 gears, but that is MY fault. I have been trying to be more aggressive RPM-wise and that just spins my tires.
What I really need to do is make more trips down the track, after I install my line lock, and start my runs with what worked before-low RPM launch and then floor it.
Once I get that going, then I can try to inch up on my RPMs at launch.
I have Viking 18 way dual adjustable 2 knob FRONT shocks installed that I can easily adjust at the track, and rear 3 way race shocks (set at 50/50 rebound and compression). I also haven't ever tried low pressure in my rear drag radials which I'm sure will help.
I tore up the top of the line pinion snubber I bought from Mancini, so I didn't get to try making adjustments to the front shocks.
Thanks again for all of the replies and advice!
 
I didn't realize you have a manual trans. I doubt if you can get the rebound too stiff in the rear, turn it up. Radials are tough to hook with a manual. If it spins at all your done. Bias are more forgiving on a Manual. My wife's Challenger will hook on a 26x8 . 12.50 car leaving at 5000 rpm. 4.30 with a 2.42 1st gear
Doug
 
dvw said:
Bias are more forgiving on a Manual.
Click to expand...
I am here to learn. So I have a question: What tires aren't radials now? M&H Racemaster drag radials were going to be the next tires I tried, but they are radial tires according to the description here:
https://www.summitracing.com/parts/mnh-rod20
So can I assume non-DOT slicks are NOT radials?
Is there a DOT drag tire in the size range (315-325) in a 17" diameter that isn't a radial?
I may have to "live with" whatever a drag radial like the Toyo Proxes TQ drag radials I have now, or the M&H Racemaster drag radials can offer traction wise as my street tires, BUT go to a non-radial TRUE slick at the track for me to find the traction I need for best ETs....
 
M/T ET Street or Hoosier Quick Time Pro are available in bias ply.
Doug
 
Go to the Mickey Thompson website. You’ll see both full slick and street legal options in both bias-ply and radial designs. I agree with Doug and others: with a clutch, you will want bias ply tires. Radials typically won’t hook up with that harsh of a hit, and if they do, you’re much more likely to break parts with radials.
I’d look at the ET Street R Bias-Ply if you want a street legal tire.
 
LemonWedge said:
Go to the Mickey Thompson website. You’ll see both full slick and street legal options in both bias-ply and radial designs. I agree with Doug and others: with a clutch, you will want bias ply tires. Radials typically won’t hook up with that harsh of a hit, and if they do, you’re much more likely to break parts with radials.
I’d look at the ET Street R Bias-Ply if you want a street legal tire.
Click to expand...
:thumbsup::thumbsup::thumbsup::thankyou:
 
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