What are you guys using for tires on 500-800hp fwd cars?? We made 517hp 270 torque on the wg @ 17psi on 93 octane without a problem. Put the c16 in and tried to make a 22-23 psi pull. We made 75 extra ft lbs torque down low but anything over 500ish hp in the higher rpms and the tires spun causing us to lose hp.. We tried to strap it down a few different ways without success. Do i just need a 235/60/15 size drag radial or what? Dyno is a dynojet setup for awd/fwd and has tuned many 700+hp cars..

The tires used were 225 50 15 kumho ast street tire
205 50 15 bf good drag radials on 10-30 psi
24.5x9x13 m/t slick on 8-20 psi (13x9 wheel)

quick run down of the setup aiming for 750ish whp

Suspension is skunk2 pro s 12k F 18k R

Enigine
84mm ls/vtec
Pte 6765 1.15 twin scroll
2 44mm tial wgs
1000cc ids @90 psi base
walbro with inline 044
pro 1 cams
and so on

If you need any info to help with my problem please ask.. Just wanna get the high boost tune finished.. THANKS

 

Just get some big drag radials, air the tires down, strap the car down tight, then air them back up. Should be good.

Is it a big roller dynojet?

 

I used MT 26x10 ET streets. had them at 25psi, strapped it down, and it held at 800whp on a 224x

 

Ok was just trying to keep from buying a set of 235/60s drag radial that i will probably never use other than the dyno. The street tires seem to have held better than the drag radials or the slicks for some reason.. With the slicks spinning the worst. Didn't think to try to air them down and back up after strapping in down..

Yes its a big roller dynojet.. We tried strapping it from the factory tow hooks and tried from the suspension. Both yielded about the same results. We also moved it further up on the roller to try to get the spinning to stop. It was strapped very well so not sure whats going on..

The boost holds fine throughout the rpms and makes more torque when the boost is increased, just spins in the higher rpms so cant get a hp reading. Was told to get some bigger drag radials and we can try again or to track tune it up to 30 psi goal..

 

I brought my 24.5x9 et drag as a last resort, I thought for sure they wouldn't spin. Started out at 22psi and tried a few passes and spun. Lowered them then to 15psi and then 10. We tightened the straps after lowering the air pressure to make sure they stayed tight and still no luck..

 

like andy said, did you try airing them back up after restrapping? also, haave a couple guys stand in the door jambs to aid with traction if need be

 

I have no experience with running slick on the dyno, as our dyno destroys them (two small roller dyno dynamics). You can't make a full pull before they blow up. We have the best luck with large (275/50r15) drag radials, two straps over each lower control, and clean rollers. Get all the dirt, oil, and grime out of the knurls on the roller. Air the tires down before strapping then air them back up after. Goodluck.

 

Nope didn't think to squeeze them down tight with low air and then air them back up. Thanks!

 

Ya never used a slick either but thought it was worth a shot since we had already made the 2hr trip to the dyno. Gonna try to find some big drag radials. Can a eg hatch fit a 275/50/15 lol? The roller on the dyno seems to be worn with no knurl where the tires set so could this be the issue? Thanks for the help i really appreciate it.

 

On a 10" wide wheel?

Andy, are you guys using the M/T SR tire?

 

we have made 840whp on a dynojet with a 205/50/15. Not sure how your dynojet is but our's is raised up and we drilled holes in the front that allowed us to tie onto the core support and strap the car STRAIGHT down. That helped ALOT.

 

What brand drag radial were you using on your dd? Mickey Thompsons got chewed up pretty bad when they got hot.

We found using a brand new set of straps helps.

 

I made 883 on Regular dunlop tires 195/45/15 with 20psi Its all on how u strap the car

 

Knurling makes a big difference. Try and strap the car off to the side and maybe you can get it on some nicer grooves.

Nitto 555r extreme drags on 15" x 10" steel wheels

 

vht does the trick for me.. Street tires can hold around 750-800 with some vht

 

Use the tallest tire you can get in there also treating the tires with some vht a few days before helps alot...

 

We tore up a set of old drag tires on the dyno so we mounted up a set of Hoosier roadracing tires we had sitting around off another car (SCCA GP car). They performed beautifully!

The soft sidewall on the dragtires seemed to "fold" around the dyno rollers but the stiff sidewall of the roadrace tire allowed us to pull the tie-downs considerably tighter.

We were a little over 500 whp on a Dyno Dynamics machine.

 

thanks gonna try to schedule to get back on the dyno next week and try some of these things.. Just sucks making a 4 hr round trip, paying for gas, race fuel and tuner fees and getting no results.. Got everything ready to make 700-800hp and cant get the car to hook up to finish the tune.

 

we use slicks with 20+ passes on them... it tears them up a little but not enough to worry about it. we have done this for years without issues.

edit: big roller dynojet

 

I am lost as to what my problem is then, everyone seems to not have had this problem lol. We tried regular tires, drag radials and slicks.. The slicks have 20ish passes and hook great at the track but spun worse than the street tires or drag radials..

I could feel rubber flying off the slicks when we were making the passes but it didn't really hurt them.. The drag radials were peeling pretty bad, definitely took some layers off. Seems like the harder compound street tires did the best.

 

Open the doors up and Have 4 fat dudes stand in the car. That was the only way we could keep the wheels from not spinning on the dyno after 800whp.

 

Finish it on the track no better Dyno then actual mph...