RJF

u did better than me i only managed a nice 105 mph with a 12.51 run and a 1.71 60ft

RJF

what i dont like is the mph isnt there on mine but i think im going to cal tsp and talk with them tomorrow i think i might end up maybe taking this cam out and going with a t-rex cam and ask a ton more questions before i buy it

RJF

also thinking about trying a 99 up computer will it work?

silverZ98

iTrader: (6)

i have a 98z with this cam and it has the samething i have a m6 though and before my 4:10s broke it wasnt that bad but wit hth e stock gear it really bad, but i like it runs good other than that alittle saveing up for a rear that will hold and then see what happens

foff667

iTrader: (2)

no offense but with a 60' & mph like that it sounds like the cam is the least of your worries...in my instance i have problems launching because the car just falls on its face for a split second and then having to rely on the gearing(2.73) to pull it through the powerband instead of sitting on the converter...so the first 330' is useless for me...the last time out i was cutting 2.20 60 foots bogging with my hoosiers set at like 30psi lol whereas before the heads/cam/tuning i was cutting mid 1.8's with them spinning @18psi. Now I know I lost a good amount of tow end tq under 3800rpms so my combination is far from matched but hearing from some others with similar issues both stick & auto's leads me to believe matching my combo is only a crutch for this problem.

lata
Bill

samz28

You just stabbing the gas as launch? Or you brake-standing the car to a given rpm then stabbing and steering? and it bogs on both?

you got your idle up to 1000~'ish right?

Very odd indeed man.

foff667

iTrader: (2)

my car idles around 850-900 when hot...ive tried both launching off the stall up to around 2800rpms & stabbing it off idle and a little of both 1500+stab and it bogs everytime unless i severely roll into the throttle...i did about 4 runs the last time out all producing about the same 2.2 60' times bogging with a shitload of air in my rears. I probably couldve gone out on my street tires and run damn near the same times lol.

crainholio

iTrader: (2)

On the older 1990-1992 TPI software, there were two variables you could tune to correct tip-in stumbling. Acceleration Enrichment features in the software allowed you to add some temporary injector pulsewidth as the throttle was moving, similar to a carb's accelerator pump squirt. When I upgraded my old TPI engine to a TPIS Mini Ram intake, it stumbled badly on tip-in until I added fuel to the AE table.

It's hard to believe the '98 PCM doesn't have this, I checked my '01 LS1-Edit last night and couldn't find anything resembling Acceleration Enrichment there either. Very likely it's buried in the code and Ken hasn't found it yet.

crainholio

iTrader: (2)

...I just posted the question to the LS1-Edit mailing list, we'll see what we get back...

Slowhawk

iTrader: (12)

Read some of this post and think you might have another problem rather than the computer. I just tuned a 98 A4 with 3600 stall and 231/237 cam last week.We found no problems with tip in.Car runs great all around.I'm sure you'll find what's holding you back.

foff667

iTrader: (2)

that makes me feel a little better, any ideas on what it COULD be?

crainholio

iTrader: (2)

Best next step is getting some data, do you have access to a laptop and EFILive or AutoTap?

foff667

iTrader: (2)

autotap, but what do i look for? Im no tuner so im going blind here & dont feel like getting raped by any fbody shop to even attempt to find my problem. I had noticed I had multiple missfires on each cylinder but would just assume this is because of such a large cam, before the heads/cam I had no such hesitation & I seemingly hasnt effected teh top end because i mph'd about where i thought i would give or take because of bogging out of the hole im sure I lost some mph.

crainholio

iTrader: (2)

Do some normal driving around with it capturing, save the data as comma separated text, so we can open it in Excel. Do mostly normal driving varying speeds, but with a few iterations of these three processes:

-3000 to ~4500 rpm low load, like holding 1st or 2nd gear at a fairly steady speed.

-WOT launch from dead stop. Just get to ~50mph or so, don't need a full 1/4mi pass, WOT thru 1st gear and a bit into 2nd is plenty.

-WOT stab from rolling start, again don't need high speed, just roll to ~20mph or so and then nail it until it upshifts.

Email me a copy of it.

Be sure to capture the following PIDs:
-rpm
-fuel trim cell#
-long term fuel trim 1
-long term fuel trim 2
-MAP KPa
-knock retard degrees
-O2 sensor 1 voltage
-O2 sensor 2 voltage
-coolant temp

When I'm looking at the data, I take three passes at it in Excel:

First pass, I sort by RPM, subsort by MAP. See what LTFT values you're getting at the various RPM/KPa coordinates, and what fuel trim cell the PCM is operating in. Looking for zero % trims or slightly negative as a good thing. Also looking for severely imbalanced LTFT numbers between the two banks as a bad thing.

Second pass I'm looking for knock retard.

Third pass I'm looking at the data sequentially as it was captured, looking at the O2 sensor outputs as you tip into the gas. Looking for a big dip into low voltages and staying there for more than a few frames (assuming 10 frames/second capture rate).

foff667

iTrader: (2)

whats your email kevin?

Scoggin Dickey

iTrader: (34)

If you haven't already, give us a call! Jason has more experience tuning this cam than ANY other tuner out there. He knows exactly what it takes to get your car running right, and we are very affordable as stated earlier. You said you spoke to Mike from New York about his tune. He also had it tuned at another shop and even though they swore the tune was perfect, Jason was able to fix alot in it...and from what I've heard Mike is alot happier with it now!

Give us a call and we'll do whatever we can to help you out with this. Also for the low end bog, some of that is to be expected with 2.73's and that verter. 4.10's will be a BIG improvement still! Hope to talk to you soon!

-Matt-

Slowhawk

iTrader: (12)

I would think the tune is off in the low end area as you say it ALWAYS bogs.

crainholio

iTrader: (2)

We'll see what's going on in his PCM this afternoon...nice thing about OBD-2 is all that extra diagnostic checking makes for much easier troubleshooting than the old stuff.

Could be the tune, could be something mechanical/electrical. We'll take a shot at finding out.

foff667

iTrader: (2)

yah im goin to see kevin later today so hopefully we'll figure out whats going on...i dont know if its the tune or what at this point, though its the last thing i want to completely revamp at this point seeing as I'd have to go back up to cartek to get it unlocked to either play with it myself or have a mail tune or whatever done at this point.

foff667

iTrader: (2)

ttt with this one with some new findings first off I'd like to say thanks to kevin(crainholio) for his time and help today. We used efi live and found some things maybe you guys can help me out with.

1. my car runs in open loop the whole time, never goes to closed loop

2. one of my 02's is dead...will get that fixed asap

3. very little vaccum at idle ...~71KPa anyone know how much they pull?

4. car runs way lean in the low RPM/KPa ranges, based on the one
O2 sensor that is working

5. my WOT fueling looks dead on perfect from the one working O2
sensor. Granted a narrow-band O2 sensor isn't as accurate as a wide-
band, but 890mV is generally the sweet spot and you're there.

6. my injectors are hitting 91% duty cycle at 6000rpm. Not a problem
now, but a longevity concern. Should i seriously look into larger injectors? Right now ive got stock 98 injectors...i think 28lb?

Any info, help, concerns or questions? Let me know Im all ears