Dyno'd today

timk · Dec 20, 2003

i was able to get a couple of pulls today on a dyno-jet dyno.....

2000...100...230
2500...120...240
3000...150...250
3500...180...270
4000...220...280
4500...240...270
5000...245...260
5500...250...240

these are corrected numbers.

the curves are so smooth. the torque curve is nearly dead flat. the hp curve goes upward in such a nice arc.

the sound on the dyno was awesome.

i have some sort of problem, though. the air/fuel ratio was 14.5-1 at 1800rpm, then shot down to less than 10-1 at 2200rpm and was off the charts down there for the entire run. there were some eyebrows raised when the air-fuel was shown on the monitor. i think i should be afraid!

you think that would be taken care of with tuning, or is there another issue that may cause such a rich condition? funny thing is, this is with the STOCK fuel pump! i would've thought the stock fuel pump would've given up by now, but, instead, i'm rich! go figure.

for those who care, here is an exhaustive run-down of the exact mods...

thumper heads (stock valve sizes)
steeda #19 cam
crane 1.7 roller rockers
cobra intake
65mm FMS t-body
stock upper intake tube
75mm Pro-m for 19# injectors, hooked to open air element
underdrive pulleys (not on alternator)

Killercanary · Dec 20, 2003

If those A/F ratio numbers are correct, then there should be more power to be had. That does seem weird that you go from high on the lean side to off the chart on the rich side. I'd check with the dyno operator and see if they think their wideband malfunctioned. With the stock fuel system, it'd be hard to get that rich. Another possibility is that the MAF calibration is messed up badly.

thumper460 · Dec 20, 2003

YOOOoo!! Hey that is about 300-310 At the flywheel with a 15% loss in the 5 speed!! Rocking!! and with a fuel problem!! That is killer!! NOW, go home and have a Merry Christmas, and ask Santa for a fuel pump and reg!! OH yeah.... he's probably setting it up for you now!! LOL!! Have a good weekend and New Year!!

Just me.........................

Thumper

timk · Dec 20, 2003

well, i have a new fuel pump in the garage, and i have a afpr on the car. last time i checked, it was in the 42lb range with no vacuum. think i should back it off?

boy, wouldn't it be a mess if the pro-m was screwy? off the top of my head, i would blame the pro-m, but the car runs so much better, with more power, than with the stock mass air(i have switched them about 10 times). O2's are about a year old, so i sort of doubt it's their fault. that said, any sensor i have bought from NAPA has lasted about half that time, i don't know why i would expect the O2's to be any different....

S/CBlack95GT · Dec 20, 2003

The O2s are ignored during WOT, so most likely your wild A/F ratio is being cause by a faulty FPR or the MAF is not tuned right. Pro-Ms are not perfect, they have had some tuning problems over the years. I have seen some dyno charts that have an A/F ratio that looks like the Rocky Mountains b/c the MAF was calibrated poorly. Usually the problem was with the cheaper Bullet 75mm MAFs.

RIO5.0 · Dec 20, 2003

Ya Baby...Nice work Tim...

timk · Dec 20, 2003

RIO5.0 said:
Ya Baby...Nice work Tim...

thanks, andy. i'm excited to know there is probably more to come by fixing the a/f ratio.

s/cblack95gt, that's good to know about the O2's. check one problem off the list. indeed, my pro-m is a 75mm bullet. it did come with a rather detailed final check printout, showing that it was calibrated and passed inspection, for what its worth.

first and foremost, i'll check the fuel pressure, with and without vacuum. i know it is not under load, but do you guys ever use the fuel pressure gauge while running the rpms up? i didn't know if this was standard practice, or if it's advisable.

thanks for all your comments.

blksn955.o · Dec 20, 2003

Good numbers Tim, I got mine done a little after you left, and my a/f was a bit rich at 11.4-12.4, and Tom was at what his data logger said he was at on his tuner, so I guess that you run rich, better than lean.

5.0Droptop · Dec 20, 2003

i would be looking at your ignition system too. Maybe somethings not firing rght under load.

timk · Dec 20, 2003

well, it appears the wideband was operating properly after talking to others there today. i'm not bummed at the numbers, really, they are what they are. i'm just concerned with the a/f. i don't like the idea of running so far off of optimum.

i'm going to do some tinkering with the afpr. it will only be judged by sotp, though, because i don't get another shot at the dyno. my distributor, cap, rotor, wires, and plugs are new, so i don't imagine it's an ignition issue. stranger things have happened, though.

still have the old valvetrain noise, too. i have new lifters, lifter dogbones, and holddown to install in a few days. that would go a long way towards me liking the car.

WIP.......work in progress. my middle name.

tmoss · Dec 20, 2003

Tim - I have a good stock FP regulator I'd let you borrow if you want to give that a try - it's free! Any chance we could get you to scan and post your dyno print out? That Steeda cam really likes the rpms doesn't it? I'll have to remember that - it's not a good match for my ported lower.

94GTLaserRC · Dec 20, 2003

The AFR looked like mine, but WITH an FMU...Without boost, As it started, the AFR was high...As soon as it climbed, the FMU was holding back TOO much fuel and I was BELOW 10:1, Resulting in a drop of about 35 RWHP. Now, with the 36# inj, and Tweecer, My AFR is much better, but I still have to Dyno it again.

GOOD LUCK!!
RC

timk · Dec 20, 2003

tom, thanks for the offer. i'm going to do some adjusting, then see what happens. if there is no change, i'll take you up on your offer.

the steeda cam is a bit peaky. i'm using 1.7rr's, too, which may contribute a bit of low end laziness. but, i like the feeling up top. doing it again, i would of course go for a custom cam. live and learn.

i don't have a scanner, but i'll see what i can do. the a/f ratio is hillarious...it just goes down and you can't see the line...it's off the scale.

hey, 94gtlaser....what do you want for those chrome tri bars, anyway?

WhiteDevil · Dec 21, 2003

Not bad numbers thats about what i put accept i have stock heads and cam. It must be the A/F that set u back. Thats all i can think of.

tmoss · Dec 21, 2003

timk said:
tom, thanks for the offer. i'm going to do some adjusting, then see what happens. if there is no change, i'll take you up on your offer.

i don't have a scanner, but i'll see what i can do. the a/f ratio is hillarious...it just goes down and you can't see the line...it's off the scale.

If you come get the regulator, bring your dyno sheet - I'll scan it for you real quick.

Rootus · Dec 21, 2003

timk-- good numbers, nice flat torque curve. I'll be interested to see how much you improve with a better A/F ratio, maybe it's worth it to get a dyno tune even on a N/A combo. I haven't bothered, but I'm pretty lazy .

thumper460 said:
YOOOoo!! Hey that is about 300-310 At the flywheel with a 15% loss in the 5 speed!!

Thumper, you smokin' crack or something? 250/.85 == 294, not 300-310. Calculators are your friend .

Dave

1fstgt · Dec 21, 2003

if the air/ fuel ratio was that rich, it would've ran like complete ****. i think that their machine was messing up. there's no way it could've been off the charts and still run as smooth as you say it did.

timk · Dec 21, 2003

thanks for the offer tom.

i always thought i would get it tuned, but you know how money can be....i really would like to get it right.

1fstgt, i thought the same thing. 20+ people were dyno'd on the same machine, the same day. i was 4th or 5th, so people before and after have had no such reading. maybe it's off a little, but what's a little? sub 10-1 a/f is pretty bad. if the reading was off, maybe it was 10-1, or 10.5, or even 11. that's still bad, and worth looking at.

i'm going to work with the afpr, and see if there is any sotp improvements. then, maybe swap it out for a stocker and see where it puts me. if i end up dynoing again for a tune, they'll be able to let me know if the pro-m is goofy.

between fixing the a/f problem, and a proper tune, i may have a few more horsepower waiting for me.

Redsnk95 · Dec 21, 2003

Seeing that you have a bullet meter, I would try "clocking" it to get it to read the air a little better....try that if the new regulator doesn't help.

Troy

RIO5.0 · Dec 21, 2003

Tim....for what its worth...I did 7-8 pulls in one shot....6 of them were timing alone...up to 20....back to 12....lost power everywhere,,,14 was the magic number...after the best timing we went for FP...I was at 42 when i drove in....all timing pulls were 42 fp....then we dropped 4 lbs to 38....picked up 8 ponies, dialed it down 2 more...lost ponies...38 was the magic number on FP...with a mid 12 to 13 AFR...we stopped right there..all seemed cool..
We have damn near the same set-up so my numbers should put you in the sweet spot...its kinda hard with the MAF thing as you have good S.O.T.P. hit, not like its falling on its face and you can tell whats going on...Troys idea on the MAF clocking is worth trying...the 75s are kinda fussy that way...
Gonna be hard to find that bug without a dyno and widebands to see the spikes...but if its showing rich at WOT...you could always do a blast down some back road, shut it down and do the ole plug check right there....its kinda funky but thats the the old school way we do all our 2 stroke toys... and it does work...
Theres really not alot of tuning to dial em in...timing and FP are bout it...specially if it feels like it pulling hard and not missing a beat....

Onward and upward...little tweaks can drive you nuts....

Dyno'd today

timk

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