Low dyno numbers

[46addict]

Hey guys,

Before I get to my questions I'm going to do a quick introduction of myself as this is my first post on the forums. I'm not new to Mustangs as this is my second S197 and my third Mustang. My main focus right now is getting quarter mile times down and also being able to hold my own on mountain roads. Bascially building a car I can race on Friday night and drive to work on Monday so I can enjoy it as much as I can.

I bought a 2007 GT/CS earlier this year and the car had a good list of bolt ons. I picked up where the previous owner left off and installed a Procharger p1sc in my driveway. I then brought it to a reputable tuner (who shall remain unnamed for now) who tuned the car and I came home with a lackluster 429/378 dyno sheet from a Dynojet.

Though there was no boost gauge installed in the car at the time, the tuner confirmed the car made 9psi. After comparing similar setups and reading numbers on members' sigs, I should have made more power. Especially with having hot rod cams and a full O/R exhaust with straight through mufflers.

I realize all dynos have a variance and I should probably pass judgement until I get some track times, but I want to get some feedback on my setup if this is a mechanical issue. If we conclude this is all in the tune, I will be going to a different tuner when I move on to the next phase.

Thanks in advance!

 

[redfirepearlgt]

why didn't you take the time to get a baseline pull before doing the mods? that was your first mistake. few dynos produce the same numbers. had you done the baseline you would have then known the yield improvement and could have compared that to what procharger claims in HP improvements.

Take the car to the track and see what it does. Have the tuner tell you what to datalog and get him some data to review. It may be something he missed, or it may more likely be his dyno is more conservative. its a comparison device for before and after, not National weights and measures calibrated standard.

 

[Wes06]

Is this on a stock block?
If so I wouldn't be trying to push to much more hp out of it.

Rods are good for 450-500 and if that dunno reads low your pushing it

 

[46addict]

why didn't you take the time to get a baseline pull before doing the mods? that was your first mistake. few dynos produce the same numbers. had you done the baseline you would have then known the yield improvement and could have compared that to what procharger claims in HP improvements.

Take the car to the track and see what it does. Have the tuner tell you what to datalog and get him some data to review. It may be something he missed, or it may more likely be his dyno is more conservative. its a comparison device for before and after, not National weights and measures calibrated standard.

Numbers before the Procharger were 340/325. But that was done at a different dyno so I didn't use that for comparison.

Tuner believes my mileage (76k miles) and the 93 degree air played a factor. My engine is pulling 20+ inches of vacuum while coasting so it's not like my rings are shot. I think I'll chalk this up to a conservative tune.

Is this on a stock block?
If so I wouldn't be trying to push to much more hp out of it.

Rods are good for 450-500 and if that dunno reads low your pushing it

Yes. Stock block and stock trans minus the Exedy clutch.

 

[Department Of Boost]

Hey guys,

Before I get to my questions I'm going to do a quick introduction of myself as this is my first post on the forums. I'm not new to Mustangs as this is my second S197 and my third Mustang. My main focus right now is getting quarter mile times down and also being able to hold my own on mountain roads. Bascially building a car I can race on Friday night and drive to work on Monday so I can enjoy it as much as I can.

I bought a 2007 GT/CS earlier this year and the car had a good list of bolt ons. I picked up where the previous owner left off and installed a Procharger p1sc in my driveway. I then brought it to a reputable tuner (who shall remain unnamed for now) who tuned the car and I came home with a lackluster 429/378 dyno sheet from a Dynojet.

Though there was no boost gauge installed in the car at the time, the tuner confirmed the car made 9psi. After comparing similar setups and reading numbers on members' sigs, I should have made more power. Especially with having hot rod cams and a full O/R exhaust with straight through mufflers.

I realize all dynos have a variance and I should probably pass judgement until I get some track times, but I want to get some feedback on my setup if this is a mechanical issue. If we conclude this is all in the tune, I will be going to a different tuner when I move on to the next phase.

Thanks in advance!

Those numbers are 100% normal. What did you expect?

 

[mac10chap]

I've got the same mods as you minus the cams and mind made 498/445....but it was also making close to 12# of boost. That was with 100K miles on the car and in about 98 degree texas heat.

 

[07 Boss]

Yeah, your numbers seem pretty reasonable for 9 psi. Your cams are hurting you a bit though. I'm not sure why folks want to run a big sounding cam without the big cam benefits, but to each their own. I run 10.3 psi with conservative timing and am at 465 rwhp. With the timing turned up it ran another 17 hp higher. So you're running about 30 hp less with shitty cams (for running boost) and 1.3 psi less boost. That sounds about right. Dyno numbers don't mean squat anyways. Et's is where you can make comparisons in performance. Dynos are for tuning.

 

[BruceH]

More than likely the belt is slipping. The procharger belt needs to be super tight or else it just won't make boost. It's a well known issue with Prochargers, even with the separate 8 rib belt. Without a boost gauge you will never know.

Hot Rod cams go pretty well with a centri blower, I wouldn't go changing them out any time soon for fear that they are holding you back too much, especially with a stock motor. Your pre blower numbers were spot on for Hot Rods and headers.

 

[46addict]

Those numbers are 100% normal. What did you expect?

I guess I expected a bit more seeing I've added boost to a full bolt on car. If I can finagle an 11 second timeslip from this setup I'll be more than happy. Will be ordering tires when funds allow.

 

[46addict]

I've got the same mods as you minus the cams and mind made 498/445....but it was also making close to 12# of boost. That was with 100K miles on the car and in about 98 degree texas heat.

What size pulley are you running?

 

[Grabber]

Seems normal to me. Hot Rod cams are not big power cams. NSR's would have been a better option compared to hot Rods.

My 05 made 446 RWHP / 394 RWTQ @ 8 PSI with a Vortech V2 (Stock pulley the S/C comes with) Shorty Headers, O/R H, Roush Cat-back, GT500 TB and 93 Octane. I had it dyno'd in about 90 degrees on a very humid day (Chicago is known for it's Humidity) and it did not have an intercooler. The blower was also on the car for about 40K miles

Every car is different. I can bet most guys making close to 500 RWHP would probably dyno less on any other dyno.

Dyno numbers are a tool, that's about it. Sure, it's cool to know how much power your car makes and to some, dyno numbers matter more than what it does at a track. The track is not for everyone and it's the same for those that believe dyno numbers are poo poo.

Toss up a data log, maybe drop in some 100 Octane and see what happens.

 

[Department Of Boost]

I guess I expected a bit more seeing I've added boost to a full bolt on car. If I can finagle an 11 second timeslip from this setup I'll be more than happy. Will be ordering tires when funds allow.

At your boost level with those bolt one the blower really doesn't care what mods the car has.

 

[redfirepearlgt]

ON 429 RWHP @ 368T with street tires I will go liberal and say 12.30's. if you can cut a 1.8X. On DR's picking up .2 on the 60ft I would speculate 11.99...with some nice air. Hope you get it. Good luck. I went 12.32 on a 1.88 60ft (that's right on factory tires...don't ask me how) on factory 235's with 426/407T in a 2005GT running a Saleen Twin Screw tuned at that time by Brenspeed in decent air.

 

[46addict]

Wouldn't it take a 5k+ rpm launch on DRs to cut a sub 1.8 60 foot? I would think at that point my stock axles are the weak link. I'm excited and nervous at the same time about taking the new setup to the track.

 

[Candy10]

I can't crack into 11's, consistent 12.0-12.3sec/117-119mph range. My dyno numbers are 476/410. Thats on 305/40R18 555Rs with 4.10s. (on the street, should be better with prep)

FWIW, it blows the tires off launching at 3k rpm. Any less and it bogs down.

 

[46addict]

FWIW, it blows the tires off launching at 3k rpm. Any less and it bogs down.

I have 555Rs as well and this is why I'm getting rid of them for real DRs. I see 555s as street compliant tires that are slightly stickier than normal radials.

 

[Grabber]

FWIW - my 07 GT with a non-ic vortech, stock headers, stock 3.31 gears, in 100+ degrees went 12.2@113 with 407 RWHP on street tires launching off idle.

You can get into the 11's with cool weather and good tires.


Sent from my iPhone using Tapatalk

 

[Candy10]

I have 555Rs as well and this is why I'm getting rid of them for real DRs. I see 555s as street compliant tires that are slightly stickier than normal radials.

Exactly. I think they are a better tire for road course/autox than the strip.

 

[redfirepearlgt]

Wouldn't it take a 5k+ rpm launch on DRs to cut a sub 1.8 60 foot? I would think at that point my stock axles are the weak link. I'm excited and nervous at the same time about taking the new setup to the track.

Stock axles are 31 spline. They are capable IMO opinion of handling 1.5's truthfully. I just cut a 1.62, 1.64, and 1.67 on mine tonight on MT ET street R series. No issues at all. The rear axles were beefed up on the 05+ cars unlike the 04 and down which had 28 splines from the factory. You'll be fine. I ran 1.69-1.75 on my 13 Gt manual setup on ET Street II series and was leavign on 4500 RPM as well with no issues.

 

[jam07GT]

Wouldn't it take a 5k+ rpm launch on DRs to cut a sub 1.8 60 foot? I would think at that point my stock axles are the weak link. I'm excited and nervous at the same time about taking the new setup to the track.

Drag radials don't work very well with a stick car. Cars with even as much power as you have at the track run slipper clutches. I'd go straight to a DOT bias slick if you plan on running much at the track. The MT drag radial SS work great on an auto car; might be tough going with a manual. IDK, I only have about 330 to the wheels, LOL, and it's probably a less than that due to the elevation I race at.

Thoughts from those who have run MT SS drag radials and a stick in an s197?