Dyno Day

[GOLDCYLON]

Dom start looking for those ZO6 flappers

http://www.ebay.com/itm/Corvette-C6-...item4ab0349789

heres the wireless controller

[XfireZ51]

I thought you guys would be interested in whether or not I could verify my SOTP on idle quality w the SW Xpipe in place of the MFlow Xpipe/resonator combo.
I did some datalogging this morning to tweak the tune a bit. There are some spots needing additional fuel, but overall nothing major.
I had felt that idle quality was better now than before and I am posting a before and after datalog of the idle. You'll see that the motor is now idling at about 3-4kPa lower than previous. That translates to about an increase of 1" Hg vacuum. That will make the difference between using the 50kPa-800rpm cell or 55kPa-800. Can idle a bit leaner since velocity will be better.

[XfireZ51]

Returned to Speed Inc. after removing the perceived restriction of the MFlow resonator and replaced it w SW Xpipe (sans baffles, thank you Al).
The first jpg attached is from the final run of he previous tuning session.
The second jpg is of one of last three runs and I was still adding timing here with change showing up in torque. Nothing else was done to the tune in the interim. I also added the airbridge insert to keep it from collapsing. I didn't need to retighten any band clamps with the insert in place. You can see there was no significant difference between the two runs. Now whether the SW Xpipe allowed me to improve on that performance would be speculation at this point. I'd need to reinstall the MFlow resonator and run with the tune I now have. The last jpg shows the change in performance from adding some more fuel and reducing timing at WOT. Paul W and I were on the dyno for about 2.5hrs. I probably can coax it to about 430rwhp with a bit more tweaking but I decided I'll leave that for a spring run. The torque is the real improvement so far.
Remember this setup is using GVD ported heads. Our sense around the pizza table last night was that there was more to be had by re-doing the heads ala "the Greek spec". It would be interesting to get Dave Johnson's AB turtle on the dyno and see what difference there is if any. I'll post some other graphs with layovers of runs once I can get the files from Speed Inc. These graphs really don't tell the full story The layovers will show the change in the "area under the curve". The torque is increased and never less than 10rwtq difference from 4500rpm through 7000 with a peak differential of nearly 25rwtq around 5300rpm. Let me just say you can feel that.

[Pete]

So with intake cams and heads you gained 25 RWHP from your previous no heads and cams.
Differance in the heads might be 10 hp not worth the expense.

I know your looking at Paul's #'s but i would've loved to seen Paul's Z on the same Dyno yesterday,that would've been real comparison.

Lean does not make power feul does,you ever wonder why the factory ran them at 12.6-12.8 AFR
Pete

[XfireZ51]

Originally Posted by Pete

So with intake cams and heads you gained 25 RWHP from your previous no heads and cams.

I know your looking at Paul's #'s but i would've loved to seen Paul's Z on the same Dyno yesterday,that would've been real comparison.

Lean does not make power feul does,you ever wonder why the factory ran them at 12.6-12.8 AFR
Pete

I agree Pete. That would be the real compare and would also agree that with some added tweaking in the direction your talking about, I'm pretty sure it'd be about 430rwhp. Too bad because Paul did have his car there. I don't recall tho what Paul's rwtq was and where peaks occurred. I asked Marc if he thought there would be any diff between the D&M dyno and Speed Inc.
I'm posting the final run of the motor from last year. The numbers are using a smoothing of 5 which lops off about 4-5 peak hp from the graph but compares apples to apples.

[XfireZ51]

So what we can state with certainty is that with GVD ported heads annd Pete's intake cams we got 30rwhp/35chp, and 26rwtq/31ctq using a 15% driveline loss factor. Same motor, same dyno. That's the only way we can really compare. By using 0 smoothing, the graph would show 430rwhp. Actually not too shabby for a 350. From there I think some additional tweaking mostly of fuel would give another 5-7rwhp and that would really put us at about where we think it should be. And that's really the only thing we can judge unless we get other cars on the same dyno same day.

P.S. Personally I think LT-5 owners are spoiled rotten on hp numbers. We poo poo numbers under 400rwhp. I would have killed for 300rwhp in my Xfire!!!

[sammy]

i think your numbers are great and the best bang for the buck .430 rwhp will allow you to have alot of fun with the car without frying your tires in the first 3 gears .jmho

[XfireZ51]

Originally Posted by sammy

i think your numbers are great and the best bang for the buck .430 rwhp will allow you to have alot of fun with the car without frying your tires in the first 3 gears .jmho

Brad,

Thanks. It certainly gets up and goes. With street tires I'm keeping the ASR on.
In reviewing the results w Pete yesterday there was another thing to note. the car made the same hp on the first run as it had made on the last run of the previous day at Speed Inc. However, it ran leaner in this first run due to the
SW Xpipe. Where I had gotten AFR down to 13.1 in the previous set of runs,
that same calibration was showing up at a 13.4+ this time. So some of the lack of change in the hp could have been leaning of the mixture due to the Xpipe better scavenging and less restriction. When I started richening it up,
it started to pick up power.

[Paul Workman]

Disclaimer: Keeping in mind it is different (DynoJet) dynos on different (tho similar) days (conditions), its always interesting to compare general characteristics, even if absolute value comparisons have a % of ambiguity.

If I'm not mistaken Dom's specs are (Dom, correct me where I'm wrong and I'll edit this..)

Stock bottom 350
Pete's spec regrind "stage one" intake cam w/ Pete's timing
Stock exhaust cam
Watson 1-7/8" headers
plenum and IH ported by Dom
secondary throttle plates and rods removed
heads ported to Greg V's spec
3" exhaust with SW X pipe
Magnaflow (2.5" in, dual exits) muffs

Dom's final run...



Equipment comparison (my car):

Stock bottom
Stock cams
secondaries removed
SW 2" headers, X=pipe, MF muffs (same as Dom's)
Plenum ported to 37mm, septum (knife edged) and length reduced by 13%
'90 IHs ported to ~36.5mm
Heads ported and relieved by me, incorporating taper along with nuance of designs by Marc Haibeck and Pete P, aka the "FBI" patterns.
cam timing by Pete,
final tuning by Marc

My sheet from a year ago...



Of special interest is the torque curve comparisons, which leads me to believe Dom's car is leaving some hp on the table - more even than A/F/timing might buy. I have my hypothesis, y'll can develop your own.

Interesting stuff. Too bad dyno time is so pricy for us mortals (except apparently those mortals owning pizza joints!) But, kidding aside, it would be interesting to take Pete up on his offer to slap his heads on Dom's motor to ferret out the head variance. There is expense involved with pulling Dom's motor and swapping heads and dyno time. I wonder if the Registry would be interested in sponsoring such an experiment, if the porting specs were revealed. That would be between the Registry, Dom, and Pete. (I'm just playing devil's advocate)

P.

[LGAFF]

Might come down to the valve relief being the difference or the coolant injection on Pauls