06-05-2020, 02:11 PM | #1 |
Drives: 2010 Camaro 2SS Join Date: Aug 2016
Location: Orlando, FL
Posts: 294
|
How gear affects dyno numbers
So I put a gpi ss3 cam and head setup on my car 2 years ago, had it dyno tuned and it made 450/415 which I always thought was low compared to the other numbers I see online with the same setup so I thought I’d have it dynod again at a different shop but this time around I have 3.91 gears in the differential and it made 475/467. Now while the first numbers are lower, the hp/tq split looks pretty average and now they look way to close together. Does anyone have experience with dynoing different gears on the same setup? I feel like the HP is normal but the Tq should be more like 430-440.
|
06-05-2020, 02:26 PM | #2 |
I.AM.
Drives: 2011 2SS/RS/A6 cammed-n-whippled Join Date: Oct 2008
Location: NY
Posts: 2,638
|
Don't worry so much about the dyno #'s...different dynos and weather conditions will give you different numbers, as well as different gear ratios...they can result in a different amount of "driveline loss" in HP.
__________________
NY5thgen.com
|
06-05-2020, 02:38 PM | #3 |
Drives: 2010 Camaro 2SS Join Date: Aug 2016
Location: Orlando, FL
Posts: 294
|
I’m not super caught up in numbers, but I got it tuned by a guy I found out afterwards is a questionable tuner, so I was unsure if his tune was bad or the dyno read low. But now I feel like my numbers are a little out of whack on the torque side so I’m kinda just curious how much the gear affects the numbers. I’m not worried cause I know how my car performs against other cars
|
06-05-2020, 02:56 PM | #4 |
Drives: 2011 Camaro 2SS LS3 Whipple Join Date: May 2019
Location: Connecticut
Posts: 1,925
|
Well did the second shop dynotune it or just run it on the dyno? You would see if it was a tune that made a difference if they ran a baseline pull first. going from dyno to dyno you can see very large sweep in numbers but I believe a lower gear will make for a lower dyno number if run on the same dyno same day no changes. They are just numbers and mean almost nothing by themselves especially in those small margins. It's just a good tuning tool and I guess bragging rights. My car last year was dynotuned at JRE 575whp then I did a dyno day on a mustang dyno and it was 595whp, no changes were made. Its a ballpark number. Numbers that matter are at the track
__________________
Whipple 2.9 CAI ID1050x injectors ZL1 Pump JRE FPCM JMS Voltage booster JRE Rough Idle blower cam BTR .660 springs CHE trunnion kit 1 7/8 Speed Engineering Borla Atak JRE scoop 1.5" lowering springs BMR trailing arms and toe links Cradle inserts 704WHP 603WTQ 93 octane
|
06-05-2020, 03:10 PM | #5 |
Drives: 2010 Camaro 2SS Join Date: Aug 2016
Location: Orlando, FL
Posts: 294
|
No tune change just dynod today on the old tune. I care a lot more about trap speed than dyno numbers. Only reason I’m bringing this up is because I thought if one dyno reads higher or lower than the other, the hp/tq split would stay the name. I went from low numbers and average split, to average hp number but abnormal high torque
|
06-05-2020, 03:52 PM | #6 |
Drives: 2010 CGM 2SS/RS LS3 Swapped A6 Join Date: Sep 2016
Location: Spring Hill, FL
Posts: 4,570
|
Shouldn't 3.91s cause a slightly lower trap than stock gears? How would the gears affect dyno numbers...Would they?
__________________
2010 CGM Camaro 2SS LS3 Swapped A6 - GPI LS3 SS1 .647/.638, (224/237, 112 +4, 7º overlap) on CamMotion 8620 core, BTR Platinum .660" Dual Spring kit w/titanium retainers, CHE bronze trunnion upgrade, stock heads milled @ .015, Melling HV 10296 oil pump, TSP 1-7/8" long tube headers (W/Catless Off-road Pipes), Corsa Xtreme 3" Catback, GPI Ported/Rod Mod Intake, Stage 2 Ported Throttle Body, Vararam OTR CAI, Mike Norris Gen 2 catch can + GM 1LE clean side separator, 160º thermostat - Megan Racing adjustable coilovers (lowered 1.75"), MRR M017 10/11" wheels-Tuned by Ryan @ GPI
|
06-05-2020, 04:01 PM | #7 |
Drives: 2010 Camaro 2SS Join Date: Aug 2016
Location: Orlando, FL
Posts: 294
|
I’ve only seen people gain mph and lose ET with gears but I haven’t been to the track to say from experience. I’m also not really sure why gears change dyno numbers either but I’ve heard people say it
|
06-05-2020, 05:51 PM | #8 |
Drives: Camaro Join Date: Oct 2018
Location: Alabama
Posts: 673
|
Who did the previous tune? Lot of “tuners” in that part of Florida.
To put this in perspective when I lived in Tampa. Shop A mustang Dyno (who did tune) showed me a graph with 430ish rwhp. Shop B with a dynojet (went for dyno day) had me at 403 rwhp. Was it weather conditions or did the first shop fudge the numbers to make it Look better? |
06-05-2020, 06:00 PM | #9 |
Drives: 2011 Camaro 2SS LS3 Whipple Join Date: May 2019
Location: Connecticut
Posts: 1,925
|
They affect dyno numbers if it's not calibrated for those gears same way running in 3rd would be different than running in 4th. In the 1/4 if he's getting out of the hole better he'll trap higher with the 3.91s is what he means not speed on the dyno
__________________
Whipple 2.9 CAI ID1050x injectors ZL1 Pump JRE FPCM JMS Voltage booster JRE Rough Idle blower cam BTR .660 springs CHE trunnion kit 1 7/8 Speed Engineering Borla Atak JRE scoop 1.5" lowering springs BMR trailing arms and toe links Cradle inserts 704WHP 603WTQ 93 octane
|
06-05-2020, 06:04 PM | #10 |
I.AM.
Drives: 2011 2SS/RS/A6 cammed-n-whippled Join Date: Oct 2008
Location: NY
Posts: 2,638
|
from what I understand, different gear ratios will cause different amounts of "parasitic loss" (crank hp vs rwhp). It shouldn't make a huge difference, but results may vary. Different types of transmissions, differentials, driveshafts/axles etc...will also change the #'s.
__________________
NY5thgen.com
|
06-07-2020, 10:24 AM | #11 |
Drives: 2010 Camaro 2SS Join Date: Aug 2016
Location: Orlando, FL
Posts: 294
|
Yeah I guess the new gear ratio tricks the dyno into thinking it has more torque, but the gear also has More parasitic loss so the torque is a little high and hp a little low. Idk just thinking out loud, either way I’m happy with the car and it beats the cars that it should.
|
06-11-2020, 12:24 PM | #12 |
Drives: 2014 2SS/RS Join Date: Jan 2018
Location: Washington
Posts: 848
|
I would agree that the parasitic loss would be less and the drivetrain as a whole would be more efficient allowing for more WHP. Other than that, I dont think the gears can do anything more or less.
__________________
2014 2SS/RS LS3/M6
|
06-13-2020, 02:10 PM | #13 | |
GPI Sales Consultant
|
Quote:
With the cam, I can't imagine not having the 4.10s. I'd run a 4.56 if we could get it.
__________________
GPI Max Package 2.0: Brodix BR7 heads/GPI porting, MAX3 cam, ST2116LSR, BSR Max Lift rockers, LS7 LSXR with 103mm TB, Vararam OTR, Mcleod RXT, G-Force/Strange 9" IRS setup with 4.63 gear. 551whp, 11.1@124mph.
Got a question about a GPI product? Feel free to shoot me a message! |
|
06-13-2020, 04:41 PM | #14 |
old school chevy rodder
Drives: 2013 2SS/RS Manual,DM exhaust,CRT Join Date: Jul 2012
Location: Oregon
Posts: 5,587
|
Reading up you would usually find that higher gear ratios usually cause numbers to go down on the same dyno....( it has to be programmed in when changing them to the equation), anyway its formulated off the torque and your working it higher RPMs with the gears and that makes it feel more in the seat of the pants. Different dynos can be way different, mustangs are the "heart breaker"; they do load bearing as in actual driving, others mainly are not load bearing and give higher numbers.....and it can vary a lot so don't sweat it ; that's what you would find and most likely if aggressively cammed well you should be around 450 torque to the rear with a manual; and less for a automatic, the GPW cams spec out good and generally you should look at what others show for the similar with similar mods....Good Day
__________________
2021 Wild Cherry ZL1 A10, Sunroof, Data, Carbon, Nav, RotoFab Dry CAI, Elite x2, Borla ATK, Driveshaft shop
|
|
|
|
|