dyno pull questions

J

jeremy78233

Registered
which gear should you be in for dyno pull? The guy I've been using is doing a pull in 5th gear but my numbers seem very low, so I was wondering if he should be in another gear? Best as of today 206hp with tire slippage and let off around 10k because is started stumbling. BTW superman and myself are doing our own tuning just using the dyno to see where we are going. So anyway my boost guage reads 10lbs, fuel pressure 90+, timing -5 @ 60-100% throttle from 5k to redline. From what i've been reading, with this much boost shouldn't I be closer to like 280hp?:banghead:
 
I actually use 6th gear for turbo and big nitrous pulls because of the gearing to give me more time to pull than the other gears. Other than that 5th gear.
 
wow, 6th gear, that seems to me like it would take longer to spool up the drum on the dyno and actually hurt your HP numbers. Kinda like doing a car in overdrive is my thinking but I am new to this and this just my opinion not trying say as a matter of fact. If I put my bike on the dyno and did a 3rd or 4th gear pull wouldn't the drum spool up faster thus increasing my HP numbers? Just looking for some clarification???
 
welcome to the world of "dyno wars"

the numbers? mean little... what they excel at is creating a baseline to see if changes help/hurt your setup..

as far as real numbers go? you can go to 10 dynos and get 10 sets of numbers.. go back a week later and even they will change to some extent..

Do not get hung up on the real numbers, worry about the +/- from one engine/tuning change to the next..
 
point taken, so far changes have all been +'s. I was just getting discuraged with the numbers, thank for the info. I'll keep tweaking my map and see if I can't safely squeeze some ponies out of it. BTW I'm running 10lbs on a stock motor with 20k anything I should worry about? So far so good though, haven't heard it knock or lean out on the dyno.
 
jeremy78233 said:
wow, 6th gear, that seems to me like it would take longer to spool up the drum on the dyno and actually hurt your HP numbers. Kinda like doing a car in overdrive is my thinking but I am new to this and this just my opinion not trying say as a matter of fact. If I put my bike on the dyno and did a 3rd or 4th gear pull wouldn't the drum spool up faster thus increasing my HP numbers? Just looking for some clarification???
Click to expand...



Load is what "spools" up the turbo not speed. More load = more boost = more horsepower.
 
You would want to use 1 to 1 ratio which is 4th gear on the dyno. Everyone else is stupid. Its always the 1 to 1 engine to drive ratio to get true hp ratings. Usually 3 gear or 4th gear depending on the transmission.
 
mikev7 said:
You would want to use 1 to 1 ratio which is 4th gear on the dyno. Everyone else is stupid. Its always the 1 to 1 engine to drive ratio to get true hp ratings. Usually 3 gear or 4th gear depending on the transmission.
Click to expand...
1 to 1 with what? final drive? trans ratio? gear ratio? (as all this changes with tires, sprockets etc)

I am probably wrong but my guess is with most of these new dyno's (fully computerized), already have built in the trans/gear ratios and can measure accurately (what ever that is) in any gear you choose..

higher gears would provide a little less abuse on the dyno and probably slightly more stable numbers..

I have seen a few dyno sheets with HP/torque numbers up through the gears...
 
Mr Bogus said:
1 to 1 with what? final drive? trans ratio? gear ratio? (as all this changes with tires, sprockets etc)

I am probably wrong but my guess is with most of these new dyno's (fully computerized), already have built in the trans/gear ratios and can measure accurately (what ever that is) in any gear you choose..

higher gears would provide a little less abuse on the dyno and probably slightly more stable numbers..

I have seen a few dyno sheets with HP/torque numbers up through the gears...
Click to expand...

You sir are correct. You can either input the gearing changes and ratio's yourself or the dyno can calculate them for you.
 
mikev7 said:
You would want to use 1 to 1 ratio which is 4th gear on the dyno. Everyone else is stupid. Its always the 1 to 1 engine to drive ratio to get true hp ratings. Usually 3 gear or 4th gear depending on the transmission.
Click to expand...

To call everyone else stupid is going a little too far don't ya think? Especially when your the one who is truely confused. :rofl:
 
c'mon guys no need to get ugly:beerchug:, I really appriciate all the info. To be honest I really felt like the bike should have been dyno'd in a lower gear (but thats just me). Here's whats interesting to me, the guy thats running the dyno for me never asked me if the bike had stock gearing or if I changed sprockets. Should that be a factor he needs to calculate into the dyno software, because my bike does not have stock gearing.
 
I do 6th gear pulls with turbos to get a good load on motor and makes it spool,na and nos bikes I use 4th gear..Power adders are different and you dyno accordingly...
 
jeremy78233 said:
c'mon guys no need to get ugly:beerchug:, I really appriciate all the info. To be honest I really felt like the bike should have been dyno'd in a lower gear (but thats just me). Here's whats interesting to me, the guy thats running the dyno for me never asked me if the bike had stock gearing or if I changed sprockets. Should that be a factor he needs to calculate into the dyno software, because my bike does not have stock gearing.
Click to expand...



Really don't need to know that. Only if you wanted it noted on your run sheet. Gearing will not affect your hp numbers. You can see what gearing changes do as far as how fast the bike runs up on the dyno as far as speed. You can do a pull in 4th and one in 5th and you will see no change in hp but the speed will be different. If you do pulls in higher gears it gives the A/F monitor more time to get a better picture of how the bike is and that is what really important on the dyno not hp numbers.
 
Im with Goldenchild on this one. 6th for turbos, and 4th for NOS pulls.

Works every time on my Dyno.

Josh

Ryders Connection
 
well thanks guys, from what I'm hearing next time I go back I will ask for a 6th gear pull and watch a\f ratio, I'll try not to concern myself with the horsepower numbers for now, after all it does feel like a beast on the street but a safe tune is what i'm really after.
 
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