I was hoping to make 300 hp, but apparently that was too much to ask with a 2.25" b-pipe and stock muffler.

A couple of comments.

I told the dyno operator to take it to fuel cut. He thought I meant redline according to the tach, so he shut off at 6500 rpm. It looks like I might have made 300 hp at 7000 rpm if he had kept going.

I saw 10 psi on the boost gauge. My bov leaks air above that because of the soft spring I have in it.

AFR was at 13.5:1 during the first two runs. I was very surprised, since JWT told me that they would tune to 11.5:1. I used the safc to drop down to 12.5 for the last run and gained 5 hp. I'm not sure what the problem is, I haven't found any air leak between the maf and the blower inlet, which would be the only possible source of leanness due to an air leak. I'm going to call JWT and see what they have to say about it.

The runs were made in 3rd gear.

Blue traces are from a year ago, NA with prcai, y-pipe and HKS exhaust.

 

good number...get a 2.5" cat-back and you will be in the 300whp rank.

your hp reading starts to drop after 5000. do you have MEVI? or the drop is caused by the lean-mixture. what does your AF curve look like? is it more flat when you dont use an FMU?

for the leanness.....you can always switch back to a boost referenced FMU just for now until the problem solved.

 

I have a MEVI, which I assumed was working when I dynoed, but yesterday the Harlan switch flaked out. Then when I checked it last night it worked fine. So I dunno. I think it was working during the dyno and the power curve started to nose over because of exhaust choking.

The AFR was very flat and didn't change much at all with rpm. Same after I lowered it with the safc.

 

13.5? Wow...that's way off. I'd be interested to hear what JWT has to say about it.

Good numbers though! I gotta dyno.

 

I just got off the phone talking to Ben at JWT. He thinks the high afr is due to an exhaust leak, which is something I was suspecting myself. I have a slip joint at the segmented Stillen b-pipe which definitely leaks and can throw the afr reading off.

Also, the fact that I was not getting any detonation at high rpm suggests that the afr is not as high as 13.5.

 

So do you think you now tuned it down to like 10.5?

 

Yep, probably so. I'm going to try to more effectively seal that exhaust leak and dyno again and see if it changes things.

 

how's your EGT reading? it should be below 800c. since you dont have boost refernce FMU anymore....I think the EGT will be very stable and you shouldnt see the EGT drops when you go WOT.

another way to check lean mixture is to pull the O2 sensor at the ehxaust manifold....mine was really white and my AFR is 14:1 from last dyno.

 

Wow that's one FLAT torque curve. NICE!

You should have dropped the exhaust on the dyno to see what happened. Easy way to see what you "could" be making.

It would be nice to overlay your dyno with other SC 4th gens. to see the mid-range bump in power from the JWT vs. FMU PLUS your 3" elbow mod.

What kind of duty cycle are you seeing at 10psi(370cc injectors, 43psi, JWT, etc.)?

 

oops...I read your torque curve as your power curve

 

Is a 3inch exhuast too much, will you lose to much low-end torque? You might get good gains up top with the MEVI.

 

Nice numbers

and yeah 13.5 is too high..

and man if you would have gone to 7000..

300whp would be yours

 

at 10PSI with that MEVI. Interesting runs but definitely need a different exhaust your missing about 20LBS of torque and quite a few horses. You should surpass 325HP easily with that 7K RPM cut off.

 

I'm seeing 75-80% duty cycle, which corresponds well with 340 hp at the engine.


Here's an overlay of my run with Jaime's (Jaime, I hope you don't mind, let me know if you do). Both runs are at 10 psi of boost. I'm making about 25 ft-lbs of torque more at 4000 rpm, but about where the MEVI opens I start losing. Whether that is due to the MEVI not opening or due to a choked exhaust, I'm not absolutely sure, but I think the MEVI did open.

 

I just saw Requin's dyno. He's making 20 ft-lbs of torque more than me, and he has a stock exhaust from the y back. Looks like he could have easily made 300 hp at 6400 rpm.

 

He's pulling less psi on a 3.125" pulley also.

Either your V1 is getting tired or the JWT program is retarding the timing considerably?

 

Blowers don't get tired. They may leak boost, like Ian's, but my boost gauge was showing 10 psi, so that's what I was getting. (Well, okay, my boost gauge is a little off, too. I've checked against a test calibration gauge we have at work and it did indeed read about .5 psi high. So I was making 9.5 psi.)

Could be the timing, in which case I need to increase boost to take advantage of it.

 

Cool...didn't know that.

More boost =

You don't need to go past 7000rpm anyways. Just nice to have a buffer to stay away from the pesky/dangerous fuel-cut.

 

Speaking of timing....have you considered one of Techtoms' MDM-100s to monitor it? Pretty pricey though.

http://www.technosquareinc.com/mdmnis.htm

 

Not that particular instrument, but Apexi used to make an instrument specifically for Nissans that I've seen on ebay. It monitors timing among other things. I've bid on a couple but they seem to go for about $50 more than I'm willing to spend.

 

Any of you guys can use my dyno charts. Ill post the other five from my turbo runs. Use them as you please I dont care. Believe me is not like that. If I have a issue or problem I may come and ask for your help/assistance one day. Thats what this forum is for to help each other. Thats the way I feel. I dont withhold any info period and you guys should know that by now. I ll look closer at your chart since I hate browsing pics at my work computer which sucks a bit.