Dyno d the car today interesting results

[SNK3BIT]

2013 Viper GTS with ARH long tubes, hi flow cats, Corsa catback exhaust, underdrive pulley, and Arrow PCM. Car made 552 WHP and 517 WTQ.


Same shop had a bone stock 2014 Viper TA in a few months ago and showed me the file on it....the stock TA made 475whp. Go figure......




https://youtu.be/yC5xV8tvJqM

[ViperGeorge]

With a 15% loss that would be 649 at the crank. I would have thought with those mods it would have been higher.

[uberpube]

It would make a gazillion horsepower on a Dynojet.... Oh it is a Dynojet, you'd make a 127 rwhp on a Dyno dynamics..

[SNK3BIT]

With a 15% loss that would be 649 at the crank. I would have thought with those mods it would have been higher.

I agree....however a stock 2014 Viper TA made 475 at the wheels.....either Dodge is lying about 640HP factory output or the dyno reads low.

Tuner said that cars that make 550ish at the wheels at his shop run mid/high 10s at 130-132.

[Rare Snake]

Damn. I'm hitting the dyno this Saturday, I was really hoping to see 530-540 on my stock '14 GTS, but maybe not if these are the numbers with mods. :/

Also SNK3BIT, I haven't ignored your request for more pics...I'm always on the forums at work and I have no pics here. lol

[edc]

Damn. I'm hitting the dyno this Saturday, I was really hoping to see 530-540 on my stock '14 GTS, but maybe not if these are the numbers with mods. :/

Also SNK3BIT, I haven't ignored your request for more pics...I'm always on the forums at work and I have no pics here. lol

I think his stock numbers are the lowest ever posted? But if you ignore the low numbers and just compare the differences, 77rwhp for those mods isn't too far out of line... 60rwhp for headers and Arrow + ~10 for the pulley...etc

[Steve M]

What were the temps in the shop? Did you note the IATs during the pulls?

[uberpube]

What were the temps in the shop? Did you note the IATs during the pulls?

That doesn't matter with SAE correction on the dyno.

[Steve M]

That doesn't matter with SAE correction on the dyno.

SAE correction won't factor in how much timing the PCM may be pulling if the temps were high.

[1.8t]

It most certainly does as the ECU pulls timing as IAT's climb. SAE corrections account for atmospheric conditions, but not for the influence of those atmospheric conditions on the ECU.

[uberpube]

If you are looking for 50 rwhp in intake air temp correction timing, not gonna happen.

[Steve M]

If you are looking for 50 rwhp in intake air temp correction timing, not gonna happen.

You sure? http://driveviper.com/forums/threads...ght=arrow+dyno

[uberpube]

Are you trying to say all they changed was the IAT vs Timing table to achieve the gains? I'd like to see what the factory IAT vs timing adjustments are if you have them. Its actually an interesting discussion as to what the dyno sees for correction, we have to assume the the IAT vs timing table to set to achieve a cylinder pressure supported by the fuel.

[LmeaViper]

I agree....however a stock 2014 Viper TA made 475 at the wheels.....either Dodge is lying about 640HP factory output or the dyno reads low.

Tuner said that cars that make 550ish at the wheels at his shop run mid/high 10s at 130-132.

I seriously wouldn't worry about the you should have gotten X numbers, as dyno's numbers vary a lot for a number of reasons. For starters, tell us about how the additional power feels and then see if anyone has a stock one around you to compare against. If you are around me, I am game for a comparison.

[Stealth]

1/4 mile trap speed would also be good to know.

[racegate]

I would not worry about the dyno numbers. 475whp on the stock TA --> 550whp on your car is what I would focus on.

Get the car to a track or run it on a PBOX and I'm sure you'll find its performing well.

[98intrigue]

I would not worry about the dyno numbers. 475whp on the stock TA --> 550whp on your car is what I would focus on.

Get the car to a track or run it on a PBOX and I'm sure you'll find its performing well.

100%. All dynos are different. My car made 508whp stock and 571whp with UD pulley, Belanger headers and exhaust, and Arrow PCM. I'll be racing the car at FL2K to see how it does.

[Jack B]

You really have to use the search function before making misleading comments, the stock PCM kills the hp when the IAT's get into the 90's. Even the Arrow PCM pulls significant timing, an HPT tuned car can do better.

If you are looking for 50 rwhp in intake air temp correction timing, not gonna happen.

[Steve M]

Are you trying to say all they changed was the IAT vs Timing table to achieve the gains? I'd like to see what the factory IAT vs timing adjustments are if you have them. Its actually an interesting discussion as to what the dyno sees for correction, we have to assume the the IAT vs timing table to set to achieve a cylinder pressure supported by the fuel.

This is the stock IAT timing modifier:



Keep in mind that there is a linear interpolation between points in that table, so anything warmer than 77°F and it will start pulling timing (1° at 80°, 2° at 83°). On the Gen 4 and 5 Vipers, if the PCM pulls timing, it also adds fuel using a multiplier based on load and RPM. Less timing plus more fuel is not a good combo for a high dyno number.

At this point, I'm not trying to say anything about the results in the first post...without the IATs and/or AFR, it's too hard to tell if that dyno just reads low or if the PCM is stepping in due to high IATs. If the conditions were good, the dyno probably reads low.

[Rocket]

Is it the tune/conditions or a low Dynojet reading? My impression has always been that Dynojet's seem to show lower numbers overall?

[SNK3BIT]

You sure? http://driveviper.com/forums/threads...ght=arrow+dyno

UHHH.....HOLY CRAP!!! I MAY BE GOING BACK FOR A CUSTOM TUNE.....LIKE TOMORROW!!!!!!!!!!!

I would not worry about the dyno numbers. 475whp on the stock TA --> 550whp on your car is what I would focus on.

Get the car to a track or run it on a PBOX and I'm sure you'll find its performing well.

AGREED......the massive difference means the mods are working like they should and could just be the dyno.....oh and whats a PBOX?

You really have to use the search function before making misleading comments, the stock PCM kills the hp when the IAT's get into the 90's. Even the Arrow PCM pulls significant timing, an HPT tuned car can do better.

Can the ARROW pcm be tuned or should i reinstall the stock pcm and have them tune it? Does it require unlocking etc?

Damn. I'm hitting the dyno this Saturday, I was really hoping to see 530-540 on my stock '14 GTS, but maybe not if these are the numbers with mods. :/

Also SNK3BIT, I haven't ignored your request for more pics...I'm always on the forums at work and I have no pics here. lol

that color scheme is badass

I think his stock numbers are the lowest ever posted? But if you ignore the low numbers and just compare the differences, 77rwhp for those mods isn't too far out of line... 60rwhp for headers and Arrow + ~10 for the pulley...etc

ditto

What were the temps in the shop? Did you note the IATs during the pulls?

temps in the shop ranged from hot to stupid hot....it was noon in florida if that helps.

[SNK3BIT]

For easier viewing....this guys first runs were almost identical to mine.....after custom tune he picked up a ton of power.

[SSGNRDZ_28]

IAT can be 60+ degrees F over ambient at idle heat soak... Timing is pulled at 77 degrees F. This is why the intake heat shield was developed.

Sheild Results Idle vs 40 mph.jpg

[SNK3BIT]

IAT can be 60+ degrees F over ambient at idle heat soak... Timing is pulled at 77 degrees F. This is why the intake heat shield was developed.

Sheild Results Idle vs 40 mph.jpg

I have a DSE heat shield too....gold foil wrapped

[uberpube]

IAT can be 60+ degrees F over ambient at idle heat soak... Timing is pulled at 77 degrees F. This is why the intake heat shield was developed.

Sheild Results Idle vs 40 mph.jpg

That having that much affect would depend on the dynocell fan setup, or lack of it. OP would have to detail that.

This is the stock IAT timing modifier:



Keep in mind that there is a linear interpolation between points in that table, so anything warmer than 77°F and it will start pulling timing (1° at 80°, 2° at 83°). On the Gen 4 and 5 Vipers, if the PCM pulls timing, it also adds fuel using a multiplier based on load and RPM. Less timing plus more fuel is not a good combo for a high dyno number.

At this point, I'm not trying to say anything about the results in the first post...without the IATs and/or AFR, it's too hard to tell if that dyno just reads low or if the PCM is stepping in due to high IATs. If the conditions were good, the dyno probably reads low.

Also remember the dyno corrects the raw number higher with warmer temperatures, the question is does the correction of the dyno of the raw number upward match the power loss from the reduced timing, which I think it does as the J1349 correction factor is from standard conditions of 77 deg, right where the IAT tables start. I can tell you this with certainty , on a given day, every efi mopar I have dyno'd has registered more power as the vehicle got warmer and then plateaus . I attribute that the fluids warming up and less loss as oil gets hot, you'd think with the engine and then the intake getting hotter with engine temp it would fall, but it doesn't. I found that out playing with the diablo trinity on the jeep, to test its tunes I had to do runs each time till it plateaued continually.
Dynojets are calibrated to the dynojet standard,a dynojet that is reading inconsistent to other dynojets, is a broken dynojet.