DirtyDaveW

If everything stays as it is, I should be racing next Friday night at Lebanon Valley. This will be my first time on the track with this new turbo and the SD tune.

blkchevyz

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good luck at the track.

blkchevyz

did you make it to the track?

DirtyDaveW

Yes. Several friends, enthusiasts and I rented the local track for the day. There were around 30 racers. I think it was Redline that got the whole thing going. There was a late model Cadillac SUV that was running an E85 turbo assisted 10 sec runs. Wicked.

On my setup...
I have some things to iron out. My sixties were still in 2.xx land and it was lazy out of the hole, but my 'butt dyno' thought it was still trapping well. It certainly was running flawlessly in terms of AFR but the boost would not get above 12 psi no matter what fiddling I did with the boost controller. I was watching the boost gauge after each shift and it seemed to be locked to 12 psi. Normally I'm running 15+ with the old kit. I bought some plugs for the cold side today so I can try to see if I have a leak somewhere.

Next, this particular tune has much less total timing when in full boost. My MAF tune still had no less that 21 degrees of advance at 80 KPA and above where my tune that night was running Dookies (as low as) 15 degrees.
I’m loading some timing from my MAF based tune for max KPA (8o kpa +) to see if that helps.

One other thing that I think is hampering performance. Due to the configuration of the kit and the consequent turbo inlet location, I have the smallest Air filter of any I've seen for a 4".
I *think* that may be restricting my power. This filter is right on the turbo w/o any tubing.

My old kit had the largest K&N (same size as that red Spectre in the back of the picture) I could fit in there. I’m going to pull off that filter and see if I can either adapt my old ‘cobra’ turbo/air elbow to this setup or perhaps make a Fiberglass one from scratch(no pun intended) so I can get a full size filter on it.


I only made two passes though I could have stayed and hotlapped 20 races. But I thought, “what's the point if the car is not running right?” Both passes were near identical. When I made the passes, I thought it was really running well but I was shocked that the MPH was almost 5mph slower than my old setup. Pressing the history button on the AEM True Boost helped make me feel better in that I was only getting 12 psi

60 foot: 2.xx
1/4 ET: 11.9x first pass, 11.8x second pass
1/4 MPH: 125 first pass, 126 second pass.

Another frustration was that, due to my last minute preparation (Isn't that an oxymoron of sorts?) I couldn't get my 2 step configured. I *think* I have it conceptually setup now but I have to go out and test it.

Now that I'm between jobs, I hope I can take out the T56 and put the TH350 and 4,000 stall Vigilante before trying the track again.

DirtyDaveW

Went to the track again with the 2 bar SD tune and the 2 step configured correctly. I did set it up in a way that I *thought* would benefit me but I now believe it may have slowed my performance a bit.

I got a window switch ("Reed style") and put the rod magnet on the clutch pedal arm up high. The sensor portion, I put on the 'under dash'. In this way, anytime I had the clutch pressed, the rev limit (4,400 rpm) would be activated. I had reasoned that this would be good

• I could have the RPM locked at a consistent point for the launch
• I could 'speed' shift by keeping the gas pedal planted since the rev limiter would keep the motor from over rev'ing during the shifts, thus (I thought) making the car quicker.

Watching the video, I realized there's actually a fair lag between gears now and when the shift from 3rd to 4th occurred the fuel accumulation resulted in quite the backfire. The track announcer thought I'd activated a N2O kit and it had backfired. They even had a track Marshall at the end of the track check my engine for leaking fluids, suspecting I might have popped the motor. All was well though.

Another thing I'd done prior to attending the track was to take off my manual boost controller and hook up my old AEM Tru Boost electronic controller. This allowed the PSI to rise to 14.x

What *was* suprising, in a good way, was I ran 2 back to back passes(Only ran two time trials and redlighted in the actual eliminations of 'street' class)

• Sixty foots: 1.9x
• 1/4 mile ET's: 11.7
• 1/4 mile MPH's: 125

This straight off the highway, onto the track, full body weight/interior, daily driver tires.

At any rate, I'm putting my 2 bar SD tune out there for anyone that wants to look at it/use it as a baseline.

Keep in mind this tune is;

• 355 cubes
• Fully ported TFS heads
• Turbo cammed
• 60# mototrons
• 2 bar MAP sensor
• Open loop only
• Ported LT1 intake
• 8.5:1 compression ratio
• MAF sensor in place, just not used (I like using the MAF screen to prevent any particulate from getting into the motor)
• Front mount air to air intercooler

Daily driving with this tune, when fully at operating temperature (1st quarter mark on the gauge no matter whether I'm racing or cruising) runs at 14.x AFR at cruise, has EXCELLENT DFCO behavior(no bucking, etc as it transitions). Under Boost it runs AFR's of 10.x at first, then goes to 11.x and 12.x as the PSI/RPM's increase.
http://www.taekwondoplus.org/z28/Tur...0130924_01.bin

In the search for more PSI from this boost controller, I've laid awake thinking at night and pondered while in the shower, "How can I get this WG to not open till I get 17 or higher psi?!". It has been frustrating to have a better hotside and larger turbo but only get to 14 psi (and typically, much less) with every configuration but one. That *one*, described as 'High boost' configuration, had a tube from the turbo outlet to the top port and a tee off the turbo outlet to the boost controller (set to wide open) that went to the bottom port of the WG. In that configuration, it went to 24psi the first time I stepped on it in 2nd gear before blowing the intercooler pipe clean out from under the car, lol.

So I thought, "there has to be a way to control that configuration (the %u201Chigh boost%u201D one) and I thought of a solution last week. I set it up and I'm testing it now. At this point during initial testing, I've got 17psi anytime I want it and its set to the 'low' range. I want to fully test it before I say what I've done. I wouldn't want someone else to try this and blow their motor.

Thank you all for sharing all the things you guys have tried and then written up here. I'm "standing on the shoulders of giants", benefiting from the great things you've all done.
Thanks,
Dave

POLOVETTE 94

I have a 94 Corvette with a 383, LT4, Vortech Strim, with a 2bar MAP and a speed density tune, making 10+lbs. of boost. I have been trying to get the air/fuel ratio dialed in better, and have a few questions, as to which tables to change. It seems to go way rich at WOT. The wideband is wired into the A/C pressure switch input so I can display it on Datamaster, and it goes to around 10.3:1 at WOT. Should I lower the numbers in the %change to a/f ratio at WOT vs. Coolant temp table, or just take some fuel out at the higher MAP pressures in the VE tables? I have been doing lots of reading on Tunercat, Datamaster, and tuning in general, but every time I feel I get it, more questions come up. Any help would be greatly appreciated.
Thanks,
Darren

blkchevyz

hows everyone doing with this? sad i still havent got my **** running yet, but hope to this springs.

DirtyDaveW

Sold my Turbo LT1 last year to Bryan Fields. He's making it a twin turbo, I think in an Impala SS. I'm still doing turbo in my '96 but it's a built 5.3. Cam, heads ,pistons, Rods, blueprinted block. TH350 w/transbrake and 4000 stall vigilante. Finally got some fats/skinnies on some Weld lightweight wheels too.

POLOVETTE 94

Anyone still here?

DirtyDaveW

I still get email notifications when someone posts in threads to which I've replied.

Sleepy_Z

Darren, i would make little changes on one table at a time to see if that's what you're looking for. I would edit values in the higher MAP pressures in the VE tables.

DirtyDaveW

Sleepy_z is correct. Modify the VE tables. Lets say an intersect of 5000 rpm and 120 KPA is showing rich, ,as you say, and in the tune that cell has a value of 95. To decrease the fuel, decrease the 95 to say 93. Then blend the nearby cells so it's not a stark change. Save that, upload it, drive and scan it and see if the wideband reading is better(leaner).

Dropping the value in the cell, the leaner it runs at that intersection of RPM/KPA.
Increasing the value in the cell, the richer it runs at that intersection of RPM/KPA.

POLOVETTE 94

Thanks guys, for still being alive
I know this is old stuff, and none of us are getting any younger. Like many, I have drifted away, as life seems to get in the way. But I just got this round of mods done (ARH headers and 3" x pipe, water to air intercooler setup, replaced all hoses and belts, replaced heater core, replaced radiator, replaced stereo, Mark Williams chromoly halfshafts, etc.) and I want to get it right and actually drive it before I die! I completely understand the VE tables, raising the number adds fuel at that RPM/MAP value, lowering leans fuel. I have the wideband/ac pressure switch/datamaster thing worked out too, so I can see where it needs to be adjusted. I was just trying to figure out the % change to air fuel ratio table thing. As others have suggested, I have the RPM one zeroed out, but at normal operating temp (80c, 176F), I have 12.1 in the coolant temp table. So if I understand correctly, 14.7 / 1.121 = 13.11. Is it still richer because the numbers in the VE table are high, and they are both working to come up with the low 10.x : 1 AFR? If I change the coolant table to say 25%, then it would target 11.76 AFR, but then I would have to drastically lower the numbers in the VE tables? Thanks in advance.

Darren

Sleepy_Z

I'm not for sure but you can try it to see what it does. Test, test, & test to see what changes what. Good luck