Cummins Diesel Forum banner

I think the dyno was wrong.

4.2K views 39 replies 14 participants last post by  CumminsBeast  
#1 ·
Well I finally got to dyno today and I think it was off. From what I understand they never even loaded it. My first pull was 569hp and 1080Tq. I ran the ADR comp1 pl10, no smarty and sprayed a 60-70hp shot of nitrous. Then the guy said My tire was hanging half way off on one side and I couldnt make another pull with those tires. that initially gave me hope that it was dragging but it looked like it had spun on the roller. I pulled off and ended up putting stock tires on since I drove almost 3 hours to go. The next three pulls were all right above 540hp with nitrous then the last was only like 471Hp with no spray. Call me crazy but wouldnt it take more than 471Hp tp propel my truck to a 12.85 1/4 mile on fuel only? I was really expecting to be over 600 on spray.
 
#3 ·
Definetly not a first timer bud. I've been well into 500 for a long time now. I seriously doubt I lost HP going to twins bigger sticks and spray.
 
#5 ·
Yeah I know, it just sucks I was over 500hp for so long with a small single and smaller injectors and now this. I would have swallowed 500 even on fuel but 475 is hard. I think some tuning and I'll be back up there no problem I just changed way to much stuff all at once.
 
#9 ·
Yeah it should be 530-550 but without the bottle.
 
#12 ·
yes, it was a dyno jet... they had needless to say not set up the best... i thought tommy was goingg to come off of it once..

That makes 2 of us. the dude snugged the straps after that pull.

Pete the cal. # sound right, most of the time mine are 50 hp off to the lower.
TOMMY
 
#38 ·
That guy in the backgroudn with the shrieking laugh is hilarious!
 
#23 ·
I've made up my mind that the dyno was wrong Pete not sure what reason it just was. A truck doin 12.85's in the 1/4 should be way high 500's or low 600's. It also didnt help that you had guys who were sorta new to it running the dyno.
 
#24 ·
Let's see here.
Was on a dyno last weekend.
Width of rollers at outside edge, 6' 8".
Width of my tire tread at outside edge, 7' 1".
Guess I was hanging over a little.
Yes there is a lip at the edge of the drums, but it's lower than the drums.
If not, you would have a cut around the entire tire tread.
As far as spinning your tires on the drums, yea, 1170 HP might do that.
In Lloyd's video it squealed, but white smoke at the tires, not.
I also never have to worry about doing that.

Brad
 
#26 ·
So there was a cut in his tire?

Brad
 
#27 ·
We assume it spun because half the tire was hanging off. I dont have a locker just an LSD. So if the rear never locked itself and 569 hp went to half of 1 tire that could have been the reason the half that was on was all gummy when I pulled off.
 
#28 ·
Well I think I have figured it out partially. After talking to Tommy I only used 1lb of nitrous out of the bottle. It did have a hissing leah so I'm supposing that that could be where the 1lb went. Looking at the vids on the 475 run that I thought was the only fuel only run the truck down shifted so that could account for the lower # on that run if the solenoid never opened on any of the runs. I ran a 12.71 1/4 mile on fuel only tonight so Either way I think the 475 is bogus.
 
This post has been deleted
#30 ·
That's with just a little tinkering. I still haqve lots of tuning to do. I wanna at least get to 12.50's or 12.60's before I spray at the track again.
 
#33 ·
It looks like I need a nitrous kit first it wasnt working the other day. I think I used Tommy's 1lb of nitrous through that leak it had. But of course that could just be an excuse?
 
#35 ·
For all the pulls I made I would definetly think more than a pound.
 
#39 ·
hell, we had to drop chris's (Lem's) tire pressure down to like 25psi, load up like 6 peopl in his bed and jump up and down while Joe was tightening the rachet-straps. then we aired his tires back up to 30psi......and he STILL spun on the rollers....didn't even make it past 45psi, barely got the second charger to light..... but I dont know what kind of dyno it was on (ASF machine shop's). Only puffed out like 604hp or something like that, smelling rubber the whole time. I'm thinking if he sticked and got to his full 60psi and water meth, he would of been in the mid 700's