Dyno Results, 275rwhp and 323rwtq

[Afshin]

Nice to see the two runs with the AFRs, very informative. I'd love to see the second dyno run when you play with the timming.

Also curious, what octane were you using for the high boost runs?

[Guest bastaad525]

At 180 kpa' date=' the timing is set at 21-22 degrees

At 200 kpa, the timing is set at 18 degrees

At 225 kpa, the timing is set at 16 degrees

 

During the runs, we NEVER heard any detonation. We attempted one time to up the timing and got a wierd dip in the power curve, so we changed the timing back.

 

We had our hands full getting the A/F straightened out and most of the two hours of dyno time was spent getting a smooth 12.5 to 11.5/1 curve. We'll try timing on the next go around.

 

I am dissappointed now in the numbers, thought I had really done something to get that kind of power out of a T3 on an L28. Guess I am gonna have to turn some screws![/quote']

 

 

Nah I wouldn't be dissapointed... really those are great numbers for the stock T3... at that boost level you're not gonna get a whole lot more out of it, it's SO far out of it's efficiency range, well past the point of diminishing returns. Again, about comparing to say, Garrett 76's numbers, he seems to be more the exception than the rule.

 

Case in point, there were at least TWO other members here who dynoed recently, with much more efficient T3/04 turbos, both running about 15psi of boost I believe, and both of THEM put down about that same amount of HP (275 ish).

 

A weird dip in the power curve after advancing the timing might well have been detonation, even if you couldn't hear it.

 

Also, your curve looks REALLY nice for a stock T3... most stock T3's I've seen dynos of up til now (like mine) torque starts falling off sharply at 4000rpm, whereas yours carries on nice and flat to just past 4500. That right there is probably one of the benefits of you running MS.

 

With my current setup, just judging from the last few times I dyno tested, I was estimating just about 250rwhp at 15psi if I'd decided to turn it up. I think that's a pretty average number for that amount of boost... so it makes perfect sense to see 275 at 18.

 

About what Sleeper said... I agree you're living on borrowed time at that boost.... though there are a few daredevils here who've been running 18 or even 20psi for quite a while (Jersey and others).... I know *I* wouldn't do it, max I'd run mine at would be 15psi, and even that isn't really doing it any favors. That's why I turned mine back down to 13... I don't feel like replacing the turbo any time soon.

 

So what I'm saying is... don't be dissapointed, those are actually really good numbers, MS or not, and anyways, you can be sure you are getting much better driveability and gas mileage out of the MS, even if it's not making all kinds of extra power. Your tune is probably fine as is, the 'rest' of the power might just be hidden in things like a bigger throttle body or full mandrel exhuast.

 

 

 

EDIT: Question - couldn't you lean out the high RPM range a bit? It's my understanding that you only need it to be on the rich side when the torque, and hence cylinder pressures, are at their highest. So once torque starts to fall off I would think you could lean it out a tad w/o fear of detonation, and should be able to gain a little bit of power there from that. My fuel curve works like that... it's at about 10:1 in the 3000-4000rpm range, where torque peaks, and then slowly leans out to a mid 12:1 by 6000rpm, by which torque has fallen off by about 100 lb ft. I've never had any problems with detonation with it set up like this.

[Guest Loose_Screws]

Good info 525, I think we'll give that a try, leaning it out in higher rpms. I do like the fact I have good torque down low and I think with a little work, I can get some more HP down there (get faster spool up with timing).

[Guest SBD]

Question - couldn't you lean out the high RPM range a bit? It's my understanding that you only need it to be on the rich side when the torque, and hence cylinder pressures, are at their highest. So once torque starts to fall off I would think you could lean it out a tad w/o fear of detonation, and should be able to gain a little bit of power there from that. My fuel curve works like that... it's at about 10:1 in the 3000-4000rpm range, where torque peaks, and then slowly leans out to a mid 12:1 by 6000rpm, by which torque has fallen off by about 100 lb ft. I've never had any problems with detonation with it set up like this.

 

Hey guys... I was the one behind the laptop so to speak.

 

I don't know if I told Loose_Screws, but actually, one of the reasons I left it rich like that in the high RPM's was because I know this was high boost + stock turbo, and that this car see's A LOT of autocross time... and I wanted to try to cool the EGT's in the upper RPM. This tune is far from perfect, as stated we had a booger of a time getting a/f right for the time that we spent on it. We had literally 1 run and 5 minutes to mess with timing. I've been looking over the file and graphs and I'm pretty sure we'll mess with timing. I REALLY don't like the bumpyness after max-hp. I've still got a bunch to look at though.

 

I would really like to see what timing graphs you guys use with this head design (which is new to me).

 

[Guest bastaad525]

so the uh... 'pessimistic' of us were right, there is definately some more power to be unlocked there, at that boost level. I always feel like the 'bad guy' when I come into one of these dyno threads and say that same line "well I'd think you should be getting more power at that boost" but usually in the end it seems I'm pretty spot on with that thought *ends tooting his own horn*.

 

 

My oppinion though, still goes along with sleeper Z... turn the boost down a bit, then fine tune the MS to get that same amount of power + a much happier longer living turbo and engine

 

With boost turned down a bit you should easily be able to run some more advance AND a bit more lean especially on top, but then again if you're doing autocrossing then SBD might have the right idea about keeping temps down. For autocrossing being a little 'down on power' isn't SO bad anyways, as you don't get to put that power to real use anyways.

[Guest Loose_Screws]

SBD (Joe) went for a ride around at AutoX. Power is NOT an issue! I really, really, really need an LSD to harness the power. I was told Nissan Comp. has a direct drop in LSD for ~$680.

 

We'll get some more dyno time soon, but need to do some 'road' tweaks first, like getting throttle enrichment adjusted, etc.

 

Thanks Joe for all your help!