[danhr]

Originally Posted by Booher

The little difference between the two, is, at least what I think is, he used a correction factor with the stock dyno,(which made it higher)and didnt with the new numbers (which caused them to be low) . I read up a bit on the dyno dynamics unit, and it's common for people to do 1.1 as the multiplier. There is a shop in cali that does 1.3, their argument is so its close to the dynojets surrounding them. If I were do use 1.1 it changes the hp to 485, which is about where it should be I think. Does this sound plausible? You are right though, I really shouldnt worry about numbers, but, it's hard to tell someone I'm nearly all full bolt ons with this number, the people I have told think I'm lying about what parts I put onto the car. I guess, now is a good time to challenge them to a race eh? Lol, I had ted from janetty racing tune it, so I'm sure it was done right, but it never hurts to check. Can hp tuners show a misfiring cylinder? My wideband showes high 13's to low 14's. I had a spark plug wire fall off once while getting a data log and the car had a different idle. It was the rear passenger boot, fixed it and it hasnt ran like that again, doesnt hurt to double check em all again though. Some good ideas, thanks guys

If your second dyno sheet is uncorrected than that's a huge problem.

Correction factors are to be used to "correct" dyno readings for the weather. When it gets hotter in the dyno room, or there is more humidity, your engine makes less power and vice versa. Correction factors are SUPPOSED to be used to try to mathematically correct this and set a standard weather scenario. The most commonly used one is SAE, which is 77ºF, 29.23inHg, pressure, 0% Relative Humidity. So let's say if you make a pull in the summer and its 90* in the dyno room, well your correction factor is going to be higher, because your car will make more power in the standard 77* condition. Also vice versa, if its colder. This is to allow you to compare dyno numbers from say different days/months/years and have them still be an apples to apples comparison.

What a lot of (crapy) shops will do, is fudge around with their correction factors and manually manipulate them, so their dyno reads higher... because no one likes going to a low reading dyno and people like going to a high reading dyno for ego purposes. It's an amateur practice and imo a sign that you shouldnt use that shop, but that's just my opinion.

Fortunately the ambient settings are saved from your pull and if you ask the shop that you want both dyno sheets in SAE, they should be able to supply you with them, without you having to redyno your car. Those two sheets will give you a representation of how much you gained with your mods, instead of now, in which since you have one corrected and one uncorrected, they are kind of pointless.

And yes.. in your scanner you can add channels to log current misfires and the misfire history for each individual cylinder and the total for the entire engine. I have done the same with plug wires and I will pull those channels up after I mess with plugs/plug wires to double check they are all on tight.

[wnta1ss]

Originally Posted by Booher

The little difference between the two, is, at least what I think is, he used a correction factor with the stock dyno,(which made it higher)and didnt with the new numbers (which caused them to be low) .

You can clear up the cf question you have by asking him to print you or email you a dyno sheet with the old run and the new run both ON THE SAME SHEET. This way both curves will be on the same correction factor, at least that is how the Dynojet software works anyway. Your new curve screenshot also has a lower power curve on the same screen, was that an old run before this round of new mods?

[Booher]

Yes the lower line was my stock pull that he overlaid with the most recent pull above it, aka both dynos are on the same second sheet. I remember him asking me if I wanted the numbers to reflect like a dyno jet to multiply it by 1.1, silly me i said no need as I didnt realize what was fully going on. I'll shoot him an email to see what info I can get. Ill also check for misfires after work today, thanks for the info on how to do it.

[wnta1ss]

Originally Posted by Booher

Yes the lower line was my stock pull that he overlaid with the most recent pull above it, aka both dynos are on the same second sheet. I remember him asking me if I wanted the numbers to reflect like a dyno jet to multiply it by 1.1, silly me i said no need as I didnt realize what was fully going on. I'll shoot him an email to see what info I can get. Ill also check for misfires after work today, thanks for the info on how to do it.

What matters is change with your mods (gains/losses) on the same dyno, so the numbers themselves are not important. I see no reason to have him multiply it by 1.1 to make it look better, personally. I do think that the old run of ~420hp with an untuned car just having a CAI and axle-back does not indicate that the dyno was stingy when that pull was done. If he multiplied that run by 1.1 it would give a bs number in other words. The gain shown on the second screenshot is quite noticeably below expectation, so the question is, did something happen to the dyno (recalibration or ???) in the meantime, or is something off with the car.

[Booher]

He said nothing has changed. If you take the original number and divide it by 1.1 it's in the 380's which would explain why the first number was so high?

[Umbriel]

Originally Posted by Booher

He said nothing has changed. If you take the original number and divide it by 1.1 it's in the 380's which would explain why the first number was so high?

Was the second dyno done this way? Honestly 380 stock to 430 modded sound about dead on.

[JCunningham]

Your putting down just about the same as me on a mustang dyno with same mods. Your good.

[Booher]

I'm 99% sure he didnt do it the same, as he told me to multiply it to match dynojets, he said hes usually lower than most people even mustang dynos. Thanks jc, that gives me some good piece of mind. I'm still gonna check the cylinders and make sure all is well. I'd rather see it than not know and think it's ok. Thanks for all the feedback guys, that's why I love this forum!

[wnta1ss]

Looking closer at the second screenshot, it shows a significant gain in low rpm torque at 2500rpm and 3000rpm, then it starts getting closer to the old run as the revs go up. Strange.

[6spdhyperblue]

Did you ever retorque the intake manifold?

[KingLT1]

Originally Posted by Booher

The little difference between the two, is, at least what I think is, he used a correction factor with the stock dyno,(which made it higher)and didnt with the new numbers (which caused them to be low) . I read up a bit on the dyno dynamics unit, and it's common for people to do 1.1 as the multiplier. There is a shop in cali that does 1.3, their argument is so its close to the dynojets surrounding them. If I were do use 1.1 it changes the hp to 485, which is about where it should be I think. Does this sound plausible? You are right though, I really shouldnt worry about numbers, but, it's hard to tell someone I'm nearly all full bolt ons with this number, the people I have told think I'm lying about what parts I put onto the car. I guess, now is a good time to challenge them to a race eh? Lol, I had ted from janetty racing tune it, so I'm sure it was done right, but it never hurts to check. Can hp tuners show a misfiring cylinder? My wideband showes high 13's to low 14's. I had a spark plug wire fall off once while getting a data log and the car had a different idle. It was the rear passenger boot, fixed it and it hasnt ran like that again, doesnt hurt to double check em all again though. Some good ideas, thanks guys

That just confirms what I said in my last post.

[Booher]

No, I never re torqued the screws, I figured the car wouldn't run right if one came loose and caused a vacuum leak. Sounds like we may have our answer then guys, good to know! I'm still gonna dyno again at ls fest to compare to my last one there too, cause why not, lol. That's still quite a few months out though.

[Bohanan23]

I know it's a little old.. But, if it read in the 480-490 range would you believe that either? Take it to the track and see what it traps.. I bet you'll go 11.5's @ low 120's. that's what matters. Sweet car color by the way

[LIVEVIL]

Originally Posted by ssmofo

Damn my LS1 FBO firebird makes that. Something isn't right I'd believe 480 if it displayed it. Turd dyno?

LOL, no way a stock cam stock heads LS1 made 441rwhp

That's HCI territory.