Byron Today

[LGAFF]

Well did not get may runs in, too many cars breaking including a new C6. I changed the secondary injectors after my last trip

First run, missed 2nd had to completely let off......13.4@111

Second run.......12.78@114.14

For the third run I dropped in one of Dominic's tunes into the car. This tune kept the initial tune from my generic Doug Rippie chip, but increased fuel over 5Krpm. When I ran on the Dyno eariler this year, it showed lean above this range.

Ran 12.42@116.47, although it is not my best MPH(117.25) It topped my prior best time of 12.54.

All times were on GSCs, we tried to get in another run but too many cars breaking. I''l let Dominic and Hans give their own updates.

It was interesting there was an 06 Viper there running 12.9s, and a C5 z06 running 12.8-13.0 range. I guess that shows the importance of a good driver. Which makes me wonder what my car is capable of in the right hands.

LGAFF
92 ZR1
#234

[-=Jeff=-]

Ah I see you figured out where to put gas in it so it would make it there and home huh
:sign10:

[LGAFF]

Jeff,
Dominic told me that somtimes running alittle lean produces more power, so I thought if running alittle lean is good running with no gas at all would be better.

LGAFF
92 ZR1
#234
:iamwithst

[WB9MCW]

Jeff,
Dominic told me that somtimes running alittle lean produces more power, so I thought if running alittle lean is good running with no gas at all would be better.

LGAFF
92 ZR1
#234
:iamwithst

Now that is funny!!! :sign10:

[XfireZ51]

Only was able to get 3 good runs in today. Pretty nice out at Byron with 60F+ temp and pretty clear skies. Brought out 300 cars and several of them "broke" including 1 C6 at the line. Rear axle AGAIN!
I was there to test my idea of gaining more power at top end with a
plug and tune change. In all runs, I have had a tough time with tire slip when I hit 2nd gear. Tires just spin on gear change. Its forces me to get off throttle until tires grab again. These are BFGs running at 34psi.
First run was a 13.2 @ 113.9.
Second run using same calibration ends up at 13.2 @ 115.83.
Took about 3% fuel out at top end and ran a 12.9 @116.48

That's my highest trap speed to date by about 1mph. Its more in line with what I have been expecting. Definitely need tires!

I may try one more trip to strip for the year to see if any leaner gains anything. ;)

[jonszr1]

dominic . did you ever try that prom i sent you without any of your changes ?

[jonszr1]

thats the prom i am using to go 118.5-120 in the quarter

[Paul Workman]

Nice trap, Dom! Mebby when I get my P&P/headers/cat back done you could show me how to tune her up. (I've always wanted to do what your doing w/ the on-board computer, but just ain't got 'round to it yet.:rolleyes:)

Anywayz, sounds like you're on the right track. Mebby time for some drag radials, huh? I'm not in a hurry to burn up my GY F1 D3s, so at some point I'm going to be looking for a spare set of wheels to mount some DRs for such shenanigans.;) You 2?

P.

[Paul Workman]

thats the prom i am using to go 118.5-120 in the quarter

What other mods have you done, if I may ask?

P.

[Pete]

What other mods have you done, if I may ask?

P.

Paul,with a good ported top end (plenum & IH's) headers and good flowing exhaust our Z's run 118-120 MPH.
Even with ported heads and stock cams i would not mess with the feul tables.

Pete

[LGAFF]

Pete,

When you say 118-120...is that one Drag radials or Street tires?


LGAFF
92 ZR1
#234

[jonszr1]

pete , so you are running the stk fueling.? after porting myinj housings and plenum, my air fuel on the dyno went to 13.9 to 1. how do you combat the lean condition/ my car detonated like crazy on the first dyno run. which was why corey took 2 deg of timming out over 4500 and added fuel to get the air fuel down to 12.8-12-9 to 1.

[jonszr1]

paul , my modds are as follows , jeal headers ,fidanza flywheel, corey henderson ported inj housings and plenum, as well as prom tune , 410 gears, z industries reverse air cleaner,flowmaster exhaust .car trapped 117.5 best with this set up , them had spin tec custom do a exhaust for me and it now trapps 118.5-120

[Paul Workman]

Paul,with a good ported top end (plenum & IH's) headers and good flowing exhaust our Z's run 118-120 MPH.
Even with ported heads and stock cams i would not mess with the feul tables.

Pete

Interesting. You are a Z guru, so I weigh your words heavily. However, being our Zs use derived AF (via MAP sensor) vs. a direct reading visa vis MAF sensors, the ECMs don't know exactly what the change in air flow is after porting, etc. It still determines it by indirect method; calculates air volume based on the MAP, temp, etc, etc and then refers to the on-board tables. So, if a particular LT5 (mine) was on the edge of lean w/o the added air provided by porting, etc, then the additional flow could be trouble...or at least I'm concerned (in my case - see AF graph from recent dyno run (below)).

http://i185.photobucket.com/albums/x220/6PPC_bucket/Vettes/Basecase-DynoZR-19-20-08LargeMedium.jpg

Soooo..... Among other things, I would like to veer away from that 14.0:1 A/F ratio before doing the top end and headers. :( After looking at the graph, what thoughts come to mind?

P.

[-=Jeff=-]

I have a comment..

on that dyno run where was the Wideband O2 placed? I will assume tail pipe, if that is the case, don't you also have Cats? I am pretty sure the Wideband may not be as accurate as you think after the exhaust goes through the cats..

[jonszr1]

Pete,

When you say 118-120...is that one Drag radials or Street tires?


LGAFF
92 ZR1
#234 mine was done on et street drag radials run at 22 lbs .

[jonszr1]

videos on u tube that show some of the actual runs are under bradley taylors zr1 at famoso

[XfireZ51]

...Even with ported heads and stock cams i would not mess with the feul tables.

Pete

:confused:

I found the need to modify both the VE and SA tables.

[XfireZ51]

Originally Posted by Pete
Paul,with a good ported top end (plenum & IH's) headers and good flowing exhaust our Z's run 118-120 MPH.
Even with ported heads and stock cams i would not mess with the feul tables.

Pete:confused:

I found the need to modify both the VE and SA tables.

I have a comment..

on that dyno run where was the Wideband O2 placed? I will assume tail pipe, if that is the case, don't you also have Cats? I am pretty sure the Wideband may not be as accurate as you think after the exhaust goes through the cats..

Jeff,

That along with the plug cuts I did led me to believe that even tho my dyno run showed a 12.8-.9 AFR at WOT, I decided to try "leaning" out the A/F at the top. The way to check AFR is to have the WB located at the collector and prior to the cats.

[Pete]

Paul,definately something wrong there,i would put the WB before the CATS and take it from there,also the some dyno WB's could be way off.
Most all stock LT5's get a little fat around peak torque and leanout at the top but your #'s are way off.
I would try another dyno or WB.

Recently i dyno'd with tailpipe WB and collector WB between both WB's there was .5-.7 differance at the collector it was showing me
12.3-12.8 at the tailpipe it was showing higher 12.8-13.5
Now which one do i believe?
I chose a happy medium.
I played with AFR's and to my suprise anywhere between 12.5-13.2 i did not see any gains, believe me i tried.
I like to be a little fat 12.5 at around peak torque a bit leaner 13.1 at the top.

I will have to dig up some of my old dyno sheets.

I was running 118-120MPH on GS-C's (ported intake,headers,old B&B) but would need a clutch after a day at the track.:cry:
I notice if you get good traction MPH goes up.

If you guys are going to the track with street radials and are looking to run consistent ET's/MPH you'll be pulling your hair out.

I know of a 350ci ported everything,headers good flowing exhaust,stock cams making good power with stock VE tables running 122-123 MPH in circles of course on DR's.

I bet if you guys put DR's on your cars they will run more consistent and good MPH.

If i get the time i would love to take on project ZR-1 start from scratch i.e. Jeffs ZR-1 from stock to headers/good flowing exhuast to ported intake then ported heads (stock cams).
Jeff,of course you would have to pay for dyno's gaskets/parts etc.:)
What do you say Jeff,that would make for a good article.


Pete

[Paul Workman]

Paul,definately something wrong there...
Pete

"Way off"...Yeah, that's what the dyno op said too. (WB in the tail pipe after the cats, BTW) How-some-ever, - were it not for other runs made within that same hour, I'd be thinking WB error too. But! Fact is, ALL others seemed to be about what one would expect to see - 12.x to 13.x including another 90 ZR-1 two runs later (with a M Haibeck chip)!

Well, next spring I won't need to worry 'bout the cats...they wont be there. And, if yesterday's little trip to the Mississippi and back is any indication, a new clutch and possible freshing of the tranny will be behind me.:rolleyes: (More on that later...)

P.

[-=Jeff=-]

If i get the time i would love to take on project ZR-1 start from scratch i.e. Jeffs ZR-1 from stock to headers/good flowing exhuast to ported intake then ported heads (stock cams).
Jeff,of course you would have to pay for dyno's gaskets/parts etc.:)
What do you say Jeff,that would make for a good article.


Pete


Yeah we could do that.. would be slow going though, I don't see it happening all on one year

[jonszr1]

thanx for the info pete , guess i will have to weld in a wide band plug to the headers when funds become available . i need another prom for the black car before it will run . i took mine out to try another a friend gave me and it fell on the ground and i like an idiot stepped on it . thankfully he let me use his spare till i got home but had to send it back to him . hopefully dom still has the one i sent him . if not then i need to get one anyone know where i can get one .? i hear from the dealer that they are no longer available