Disappointing Dyno results:(

DennisT · Jun 27, 2005

Went to the dyno on Saturday and damn I'm completed disappointed with the numbers. Given I have a auto and I'm loosing from that alone I really was expecting more with the mods I've done so far. Now I am running a bit rich but from 2 pulls I came up with 210rwhp & 240 ft.lbs torque = not good!! The guy stated that I was running rich and my A/F ratio started out around 15 then went down somewhere around 12 then finished at around 13 or so roughly. Now I know leaning it out a little so the graph reads flat where it should be is going to help out but the thing that troubled me is the tuner (he's a reputable NMRA guy) stated that my MRT H-pipe was probably robbing hp as well I should look at a bigger MAF. He said since I was running the Accufab plenum & TB combo it's probably not getting the flow it should with the stock MAF. He also said he's seen guys running aftermarket H's and then swapping to a X and their gaining back maybe 12-15hp, obviously with a catback as well. What do I need to do here people? When I was at the shop I immediately started thinking about swapping my midpipe but then I thought no way....there's no way I should be losing hp.

DropTopPony · Jun 27, 2005

was this a mustang dyno? they tend to show lower numbers compared to a dyno jet.

ponygirl74 · Jun 27, 2005

I got 229rwhp and 242rwtq and we have similar mods except you have a tb/plenum and I have a catback. You should have more rwhp w/ your mods so I think an X pipe and catback would be bring you back up, but I'm sure someone with more experience than me can help you. From what I've read the x pipe gives more power vs. an h pipe. I just though I would post my dyno #'s so you could compare.

BTW - mine was a Mustang dyno

DropTopPony · Jun 27, 2005

ponygirl74 said:
I got 229rwhp and 242rwtq and we have similar mods except you have a tb/plenum and I have a catback. You should have more rwhp w/ your mods so I think an X pipe and catback would be bring you back up, but I'm sure someone with more experience than me can help you. From what I've read the x pipe gives more power vs. an h pipe. I just though I would post my dyno #'s so you could compare.

BTW - mine was a Mustang dyno

so he's not really off too much then. you got 19 more hp then him but he has an automatic and he's running rich. So iff thats taken care of he should pickup a couple and be 10 -12 hp behing a 5 sp....it could be worse, i dyno'd at 182hp with my npi auto when i first got it. I haven't re-dyno'd yet after my pi swap to see the new numbers.

jstreet0204 · Jun 27, 2005

1) if you went down around 12 then back up to 13, you are not running that rich. Stock calibration shoots for 12:1

2) if he is telling you that you should get a bigger MAF, he's not that reputable.

Is it a catted H-pipe? I doubt it is costing you any hp. You should see some gains going to an offroad pipe though. Besides being an auto, the deep dish wheels and 315 tires are costing you power also. Not only are they heavier, but you have more weight at the outer part of the wheel, so it takes more to turn them.

96WhiteNight · Jun 27, 2005

jstreet0204 said:
1) if you went down around 12 then back up to 13, you are not running that rich. Stock calibration shoots for 12:1

2) if he is telling you that you should get a bigger MAF, he's not that reputable.

Is it a catted H-pipe? I doubt it is costing you any hp. You should see some gains going to an offroad pipe though. Besides being an auto, the deep dish wheels and 315 tires are costing you power also. Not only are they heavier, but you have more weight at the outer part of the wheel, so it takes more to turn them.

I agree you don't need a bigger MAF untill you got some serious mods like heads and cams or a charger or turbo.

300bhp/ton · Jun 27, 2005

DennisT said:
Went to the dyno on Saturday and damn I'm completed disappointed with the numbers. Given I have a auto and I'm loosing from that alone I really was expecting more with the mods I've done so far. Now I am running a bit rich but from 2 pulls I came up with 210rwhp & 240 ft.lbs torque = not good!! The guy stated that I was running rich and my A/F ratio started out around 15 then went down somewhere around 12 then finished at around 13 or so roughly. Now I know leaning it out a little so the graph reads flat where it should be is going to help out but the thing that troubled me is the tuner (he's a reputable NMRA guy) stated that my MRT H-pipe was probably robbing hp as well I should look at a bigger MAF. He said since I was running the Accufab plenum & TB combo it's probably not getting the flow it should with the stock MAF. He also said he's seen guys running aftermarket H's and then swapping to a X and their gaining back maybe 12-15hp, obviously with a catback as well. What do I need to do here people? When I was at the shop I immediately started thinking about swapping my midpipe but then I thought no way....there's no way I should be losing hp.

I wouldn't worry too much. The numbers probably arn't that far off in all reality when ALL factors are considered.

How does the car run? What sort of ET's does it get and more importantly the trap speed. If you know the speed at the 1/4 mile and the full up weight of the car with you in it you should be able to approximate your hp.

This is only a guess but if it coincides with the dyno readings then there is probebly something in it.

Remember if it had dyno'd 260rwhp it won't have actually made the car any faster or more powerful just an alternative reading. How the car actually runs and performs is far more import than a peak claim from a dyno.

Have you got a copy of the graph? And did you get a base line dyno before any mods where on the car so you can compare how its running. If its producing more power over 80-90% of the rpm range with just a lower increase in PEAK then its probably not all bad.

Ps

One more thing, remember BHP is a calculation of torgue and engine rpms. If 2 cars produce the same PEAK torque but one of them is 1000rpm higher in the rpms the calcualation will also give it the higher BHP number.

Your torque number is about bang on with ponygirl74 but if they are making it a bit higher in the rpms due to their setup/tune and gear box they should be producing more BHP, which they are.

300bhp/ton · Jun 27, 2005

Also just noticed you have a bigger TB? But not too many other mods.

Have you had the car custom tuned?

I would guess that this may infact be hindering performance rather than increasing more than any other component. The H pipe thing sounds more like a sales ploy to try and flog you an X pipe.

I've read several posts about people adding bigger TB's to cars and getting negative gains. Or people buying cars with bigger TB's and having trouble and eventually swapping back to the original and finding the car runs better and is faster.

Ultimatley it should give BHP, but only if the rest of your setup is supporting what it can offer.

DennisT · Jun 27, 2005

Thanks for the insight everyone. It was a DynoJet and unfortunately I don't have a baseline dyno before the mods. I do have a printout from Saturday's dyno and I am running rich so from everthing I've heard a tune should get me back in the game. I'm still a bit puzzled about him saying that I may be losing hp with my H, it's a catted MRT H-pipe and I just don't get that. My car seems to run fine for the most part and I've never had her on the track. I was just hoping to be in the 230-240hp range...

trinity_gt · Jun 27, 2005

My car gained 8.1rwHP and 6 ft-lbs after going to the MRT catted H. It's not that.

210HP... That ain't right. Any chance you can get to another dyno in the area to compare? Maybe the dyno was out of calibration or something stupid was wrong (i.e. dyno brake dragging...)

At the very least the car should be in the 220s (stock) and with the intake, plenum and MRT pipe you should be 10-15 up on that.

mity2 · Jun 27, 2005

i got 240.8rwhp with just prochamber and side exhuast. Thats befor i got C&L plenum, and running 87oct. I think it was detonating bit up at the top. my car is 5speed tho.. ur car should have gotten something like 220~230 at least
are you sure u didn't dyno on MustangDyno? they do read 10~20% less. but more accurate

jstreet0204 · Jun 27, 2005

DennisT said:
I am running rich so from everthing I've heard a tune should get me back in the game.

Don't expect too much. If the richest you saw was 12:1 you aren't that rich, and the gains to be had by pulling it back up to 13:1 or 13.5:1 are going to be minimal. You should see a some gains from adding timing though. If you have your old wheels try dynoing it with those on I bet you will see a big difference.

DennisT · Jun 27, 2005

I don't have the print out with me now but if I'm remembering right the A/F ratio graph started out at around 15 then dipped to 12 then back at around 13 or so and that was on a DynoJet. I know the goal for the A/F ratio is be flat across the board - as I saw that day from a buddies graph that dyno'd after me. I'm thinking about just getting the SCT X-Calibrator 2 from ModularDepot which comes pre-loaded with two custom tunes when you send them your mod list. The car has never been tuned and this was the first time on the dyno. I didn't think it was unrealistic to be expecting 230-240 rwhp with my mods...

edbo · Jun 27, 2005

DennisT said:
I don't have the print out with me now but if I'm remembering right the A/F ratio graph started out at around 15 then dipped to 12 then back at around 13 or so and that was on a DynoJet. I know the goal for the A/F ratio is be flat across the board - as I saw that day from a buddies graph that dyno'd after me. I'm thinking about just getting the SCT X-Calibrator 2 from ModularDepot which comes pre-loaded with two custom tunes when you send them your mod list. The car has never been tuned and this was the first time on the dyno. I didn't think it was unrealistic to be expecting 230-240 rwhp with my mods...

Yeah, get those tunes loaded, then dyno test again. I'm sure it will be night and day results.

jstreet0204 · Jun 27, 2005

DennisT said:
I don't have the print out with me now but if I'm remembering right the A/F ratio graph started out at around 15 then dipped to 12 then back at around 13 or so and that was on a DynoJet. I know the goal for the A/F ratio is be flat across the board - as I saw that day from a buddies graph that dyno'd after me. I'm thinking about just getting the SCT X-Calibrator 2 from ModularDepot which comes pre-loaded with two custom tunes when you send them your mod list. The car has never been tuned and this was the first time on the dyno. I didn't think it was unrealistic to be expecting 230-240 rwhp with my mods...

Starting at 15 is normal. There is usually a tip-in spike when you step on the gas. The goal is to try to get it as flat as possible around 13-13.2 to be on the safe side. Without a tune your a/f is acting exactly like it should from the factory since the commanded value at 100% load over 2k rpm is 12.014

mity2 · Jun 27, 2005

jstreet0204 said:
Don't expect too much. If the richest you saw was 12:1 you aren't that rich, and the gains to be had by pulling it back up to 13:1 or 13.5:1 are going to be minimal. You should see a some gains from adding timing though. If you have your old wheels try dynoing it with those on I bet you will see a big difference.

yeah on my dyno ran, i think my A/F ratio dipped to something like 11.8:1.
infact, where i made most power, i was at 12.1:1

langod · Jun 27, 2005

I also think it's the 75mm TB. Get it dyno tuned -- it should make a big difference. 210 is WAY too low even without any mods.
For comparison, my 02 GT (30K mi) is bone stock and on a Dynojet a couple of months ago it put out 226hp/269Tq. That's with A/F ranging from about 15 at intial tip-in and then came down to about 12 by 4500rpm and stayed there until shutdown.

DennisT · Jun 27, 2005

I'm assuming that's from an auto as well?

04DarkShadowGT · Jun 27, 2005

Its the horespower gods mad at you because you have an APC fire extinguisher in your list of mods j/k

DennisT · Jun 27, 2005

Hah....just maybe they are It was something I saw and thought it would make a cool interior mod.

Disappointing Dyno results:(

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I like Pro3 and all I got was this crappy CT.

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I like Pro3 and all I got was this crappy CT.

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