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View Full Version : Dyno Help!! Do my numbers seem lower than they should?



SixSpeedSleuth
01-15-2007, 07:48 PM
Mods are GT2871R.64 Trim, JWT S4's, Greddy Intake Manifold, plus the usual dp,exhaust manifold, turbo elbow, exhaust. Tune is with Enthalpy and the Injectors are Deatschwerks 660s. Several people have complained that this dyno reads low, but i'm not sure. It was a DynoJet.
http://i76.photobucket.com/albums/j15/StopTheExcuses/NissanDyno-1.jpg
That was at 18.5 PSI. The lowest run of the day was 330whp at 15PSI. Suggestions anybody? Also, what gives with the late spool up? On the street it reaches peak boost around 3900 to 4100.

codyace
01-15-2007, 08:08 PM
The S4 cams will push the spool back just a tad, but they should help/create alot more torque than your are....especially at 18 psi!

Have you checked your timing correctly (and not just by restabbing the cas) and or checked fuel pressure? With similar mods to my setup, you should be at 300 ftlbs from 4000rpm to redline

gsracer
01-15-2007, 08:14 PM
+1000 on the timing

SixSpeedSleuth
01-15-2007, 08:17 PM
The S4 cams will push the spool back just a tad, but they should help/create alot more torque than your are....especially at 18 psi!

Have you checked your timing correctly (and not just by restabbing the cas) and or checked fuel pressure? With similar mods to my setup, you should be at 300 ftlbs from 4000rpm to redline

Hmmm, I have not as of recently. What exactly should I have it set at, I've seen several articles that have different opinions? Any other suggestions, I notice that you and I have similar setups. Yes, I thought the torque was a little low as well. But other than that, I like how it peaks and then stays flat until redline, plus, HP pulls to redline. Would it be advisable to build my head and run to 8000rpm? About Fuel pressure, no, I have not checked it, but it's the stock FPR. I bought the Nismo FPR, but they sent me the wrong one and I never ordered a new one.

TS4l
01-15-2007, 09:32 PM
You need to set your timing with your CAS to 15 degrees like stock. Your spool seems late. My Gt30R spools quiker than. You should be more around 3600-3800 rpm's. Good luck.

SixSpeedSleuth
01-15-2007, 09:34 PM
You need to set your timing with your CAS to 15 degrees like stock. Your spool seems late. My Gt30R spools quiker than. You should be more around 3600-3800 rpm's. Good luck.

Cool, thanks for the info. I'll try that out first thing tommorow and hopefully that fixes it. What Cams are you running?

codyace
01-15-2007, 10:02 PM
Hmmm, I have not as of recently. What exactly should I have it set at, I've seen several articles that have different opinions? Any other suggestions, I notice that you and I have similar setups. Yes, I thought the torque was a little low as well. But other than that, I like how it peaks and then stays flat until redline, plus, HP pulls to redline.

Setting timing should be done by locking the car in timing mod, and then hitting it with a timing gun. I've always used a Nprobe to lock the ecu into timing mode, but most people do not have that ability (and I'd venture to say about 5% of us on this forum even have a consult port wired in)...but to do it manually, you need to let the car warm up, unhook the TPS sensor, and the do 3-4 WOT blips in succession...but even then it's a ***** to get it to 'kick down' into timing mode.

Once there, you just attach your timing gun either to the entire coilpack wires on Cyl1, use the loop (be aware of which direction you have it clipped on) in the back, or take a regular spark plug wire, stick the one end on the spark plug, and year apart the other end, and stick it into the coilpack (and then clip the gun around that wire)....everyone has their preference, and gun type makes a difference as well. I actually tried all 3, and had the same reading at each location...we even called JWT to see how they prefer to set timing, and had the same basic conclusion we did.

Once ready to go, just loosen the two bolts on the cas, and slide it until you're reading 15 degrees, and you're set. Tighten the bolts down, plug the TPS back in, and you're good to go.

(Do ensure you set the engine to TDC and restab the CAS first, before doing all of this though! Just helps elimate any possible problems...)

You'd be surprized how many cars are out of timing, as most people simply stab, and go....


Would it be advisable to build my head and run to 8000rpm?
Unless you're running a solid valvetrain, it would not be advisable IMO to run any higher than 7850 (normal rev limit on rom tunes from JWT and Enthalpy). SR's are not Hondas, and really don't need to be revved way out to make power on a solid 'stockish' setup...now if you've got the dough to drop on the right valvetrain, and have a big turbo, it may be an idea, but I really think your car has the right setup now.


About Fuel pressure, no, I have not checked it, but it's the stock FPR. I bought the Nismo FPR, but they sent me the wrong one and I never ordered a new one.

A Nismo FPR will help as well, especially under boost! Get a little 20 dollar liquid filled jegs FPR gauge, and ensure you're set to go :D

Enthalpy
01-15-2007, 10:02 PM
what gear was the car dynoed in?

what model dynojet is it? 248c or 224x? the smaller dynojets (224x) do not provide as much load and thus turbo spoolup occurs later.

do you have another boost gauge? you may not be running the boost you think. that Tq number on that setup looks like 16.5-17.5 psi. Hp is looking good though. they should have spun it up a bit higher.

EDIT - If you go back to this dyno please ask them to not lug your engine on the dyno. they started the pull around 1500 rpm. this is totally un-necessary. WOT should be applied around 2500 not 1500.

codyace
01-15-2007, 10:06 PM
what gear was the car dynoed in?

what model dynojet is it? 248c or 224x? the smaller dynojets (224x) do not provide as much load and thus turbo spoolup occurs later.

Interesting to note! I never knew that :D


do you have another boost gauge? you may not be running the boost you think. that Tq number on that setup looks like 16.5-17.5 psi. Hp is looking good though. they should have spun it up a bit higher.

Agreed. On my original post in this thread, I didn't address the HP, because even at 18 psi it's not 'that bad' of a HP...just that the torque is way off...I just don't understand why I'm making 330+ft lbs at 20 psi vs his 260 @ 18 (or so we think)

Enthalpy
01-15-2007, 10:17 PM
i would expect around 300-310 ft-lbs at 18 psi with that setup. you will pick up around 10 ft-lbs per lb. of boost on a setup like this and this boost level. so 20 psi should be around 320-330 ft-lbs. bigger turbos wil increase those tq #'s ... but i stated them in reference to .64 a/r t2 turbos w/ NS111 turbine wheel.

i'm betting on autometer boost gauge ;-)

SixSpeedSleuth
01-15-2007, 10:18 PM
what gear was the car dynoed in?

what model dynojet is it? 248c or 224x? the smaller dynojets (224x) do not provide as much load and thus turbo spoolup occurs later.

do you have another boost gauge? you may not be running the boost you think. that Tq number on that setup looks like 16.5-17.5 psi. Hp is looking good though. they should have spun it up a bit higher.

EDIT - If you go back to this dyno please ask them to not lug your engine on the dyno. they started the pull around 1500 rpm. this is totally un-necessary. WOT should be applied around 2500 not 1500.

I'm not exactly sure the model, but I do know it looks very small and they told me it cost around $30,000. So, I would assume it's the small one. Black in color. Thats all I know. My Boost controller was reading 18.8 psi (Pro-spec B), but my actual Autometer boost guage was reading right at 18.

When I go back to the Dyno after checking timing, I'll make sure to tell them not to lug it, and rev it a little higher as it looks like HP was still rising. Thanks Scott!

EDIT. Haha. Yup, Autometer boost guage, must be cheap **** huh? What about the Pro-Spec B boost controller reading 18.8Psi? Also, the car was dynoed in third gear.

Enthalpy
01-15-2007, 10:26 PM
welp we found your spool problem...and possibly some missing hp/tq.

have them dyno it in 4th gear for sure. you loose the least power through the drivetrain in 4th gear.

And 3rd loads the drivetrain less. faster accelerating engine rpm = slower appearing spool on the dyno!

i'd like to see a 4th gear pull before we go any further.

SixSpeedSleuth
01-15-2007, 10:29 PM
welp we found your spool problem...and possibly some missing hp/tq.

have them dyno it in 4th gear for sure. you loose the least power through the drivetrain in 4th gear.

And 3rd loads the drivetrain less. faster accelerating engine rpm = slower appearing spool on the dyno!

i'd like to see a 4th gear pull before we go any further.

Will do, good catch! So, I guess my gauges are crap? Would the Greddy Pro-Spec B show my accurate boost level? I should obviously still check timing right? Thanks for everbodys input!

TS4l
01-15-2007, 11:11 PM
Yes still check your timing with a light, just to make sure. No reason to be on the dyno with it not timed correctly to make sure its running its best.


Quote:
Originally Posted by TS4l
You need to set your timing with your CAS to 15 degrees like stock. Your spool seems late. My Gt30R spools quiker than. You should be more around 3600-3800 rpm's. Good luck.

Cool, thanks for the info. I'll try that out first thing tommorow and hopefully that fixes it. What Cams are you running?

I'm also running S4 cam's. I saw full boost in 4th gear around 4200 rpm's and at 16psi made 300 ft/lbs. Good luck I bet the car is pretty fun to drive. I have tested some autometer gauges before with my labratory gauges and found them to be off a few psi on most of them. Just to let you know.

SixSpeedSleuth
01-15-2007, 11:35 PM
Yes still check your timing with a light, just to make sure. No reason to be on the dyno with it not timed correctly to make sure its running its best.



I'm also running S4 cam's. I saw full boost in 4th gear around 4200 rpm's and at 16psi made 300 ft/lbs. Good luck I bet the car is pretty fun to drive. I have tested some autometer gauges before with my labratory gauges and found them to be off a few psi on most of them. Just to let you know.

Yes, it is fun to drive. 350whp is a great recipe for street/track fun. Damn, I guess it's time to change gauges. I quess thats what I get for trying to save a little money ; ) So, 15*. Will do. Just to confirm, thats the 2nd mark from the left on the crank pully right?

Illegal Fun
01-16-2007, 08:18 AM
No, 15* BTDC is 2nd mark from the RIGHT. TDC is 2nd mark from the left. Just to be absolutely sure, reading the crank pulley from the front of the engine, left to right:
#1 = 5*ATDC
#2 = TDC
#3 = 5*BTDC
#4 = 10*BTDC
#5 = 15*BTDC
#6 = 20*BTDC

Good luck with the car man, can't wait to see a 4th gear pull.

SixSpeedSleuth
01-16-2007, 05:52 PM
Okay, so I went to my buddys work where he had a timing gun and followed Codyace's procedure for checking/setting timing and here is what I found. Before we touched the car, when we checked the timing it was a little past the 20* degree mark on the crank pully. What exactly can this cause?? So, we set it to 15* with the TPS unhooked and called it a day. Car does seem to run better, but I'm not sure of the power change until I get it on the dyno. I'm just curious as to what the timing set that far advanced was causing!