[Perdieu]

Last week we tuned my car on the dyno peak power was made at 12.6 across the board… for the number crowd 436/392. Went to the track and ran .45 and 6 mph SLOWER. So I decided to see what’s up and ordered a LC-1 WB and started doing some street logging. The first thing I noticed was the WOT A/F was at 10.01 at 1800 to 10.20 at 6500 can we say rich rich

So here are my questions:
How much power do you think I was down by it being so rich?
Has any one else noticed this much difference between dyno and street A/F’s

 

[radkon]

Hard to say how much power it was down but something seems really off. Either your wideband or your tuner's wideband may be going or were just calibrated incorrectly. I'd start there before making changes to the tune.

 

[Steel Chicken]

Agreed, one or the other were not calibrated. Judging by your slower track times, Id say theirs was off. What do your plugs look like after a 1/4mile run? Black?

 

[Perdieu]

Hard to say how much power it was down but something seems really off. Either your wideband or your tuner's wideband may be going or were just calibrated incorrectly. I'd start there before making changes to the tune.

we used the dyno's W/B on the dyno not the LC-1 so were thinking it's was off..we are 100% sure it was rich because of the extra gas being blown out the tail pipes on WOT passes..

I've leaned it out a little (12.2's) and boy does it pick up and move better, plus it sounds crisper. I'm going to finish dialing it in at the track this weekend.

 

[Perdieu]

Agreed, one or the other were not calibrated. Judging by your slower track times, Id say theirs was off. What do your plugs look like after a 1/4mile run? Black?

this was after last nights street stuff..12.2's from 1800 to 6800 WOT then killed it and costed into the drive and pulled them..

(big pic)http://purposebuilt.org/images/plugs.jpg

 

[Steel Chicken]

those look good, but those are after *you* leaned it out using your wideband right?

 

[Perdieu]

those look good, but those are after *you* leaned it out using your wideband right?

correct. I didn't pull any after the track passes on the rich set up. I decided to last night just to make me feel better that we were headed in the right direction and not getting a false A/F reading..

I just talked with someone else that dyno at the same place. He's having the same issue so it's looking like there W/B is off..

I still wonder how much power it was down..I'm thinking at least 40hp..

 

[Steel Chicken]

No way to guess that really. Depending on how well you get along with the dyno guy, you might want to call him and let him know what you've discovered. The wideband sensors on the dynos CAN be more accurate, if they are properly maintained. Maybe he slacked off.

 

[Perdieu]

No way to guess that really. Depending on how well you get along with the dyno guy, you might want to call him and let him know what you've discovered. The wideband sensors on the dynos CAN be more accurate, if they are properly maintained. Maybe he slacked off.

We get along real good my website helps promote his drag racing series so we have a great working relationship. I’ve already talked to him about needed to check his W/B.

I guess I'll find out saturday how much a difference it make's...still chasing my 11 sec N/A. Best has been 12.11 at 115 in 100* heat and a 4000+ DA then last week after switching tunes it slowed to 12.5's at 110 in 80* 3100 DA

 

[jdo6696]

well at least it was error to the rich side as opposed to making it too lean . You going to the track tomorrow? I have a few things I wanted to ask ya.

 

[radkon]

I still wonder how much power it was down..I'm thinking at least 40hp..

I'd be surprised if its that much. When they tuned mine we tried 12.8 to 13.2 and only saw a 5 HP diff. Granted your swing is much higher but I wouldn't expect much more than 25 hp. Anyone taking bets?

 

[Perdieu]

I'd be surprised if its that much. When they tuned mine we tried 12.8 to 13.2 and only saw a 5 HP diff. Granted your swing is much higher but I wouldn't expect much more than 25 hp. Anyone taking bets?

Hmm I'll bet (hope) your wrong..
lets use your math.. you say your .4 change was only worth 5 HP.. mine was off 2.8 so if .4 =5 then 2.8 should be 35hp :drink: I 'm thinking it's a little more...(that's why I asked the question )

well at least it was error to the rich side as opposed to making it too lean . You going to the track tomorrow? I have a few things I wanted to ask ya.

I'm not going till the VAMP race this weekend. I'll spend the next few nights on my "test track" getting it dailed in a little better. Drop me a PM on PB

 

[Steel Chicken]

dont fall into the trap of ricer math!

:drink: :fawkdance

 

[foff667]

ricer math FTL lol

 

[Perdieu]

dont fall into the trap of ricer math!

:drink: :fawkdance

My wife said the same thing, then I pointed out "it is an import" :gears:

 

[Perdieu]

So it looks like no one really knows the answer or has a guess because each car reacts different. Ricer math won’t work either because each point of A/F affects things differently.

So to sum it up I’ve learned nothing today that I didn’t already know. My car ran like shit in better weather on a rich tune, now that I’ve leaned it out it “should” run better the next time out.

Anyone want to guess on an ET….

 

[radkon]

Hmm I'll bet (hope) your wrong..
lets use your math.. you say your .4 change was only worth 5 HP.. mine was off 2.8 so if .4 =5 then 2.8 should be 35hp :drink: I 'm thinking it's a little more...(that's why I asked the question )

I won't call it ricer math but its not a linear equation either. More of a logarithmic equation. I'm sticking with my original bet, but for your sake I hope I'm wrong.

 

[Bone]

I took away 2% fuel at one time in my car and picked up close to 40hp and a good bunch of Tq.Why are you so stinking rich even in the 12 range. I was running around 14.2 range and was safe and made the most power.
Anthony

 

[Perdieu]

I took away 2% fuel at one time in my car and picked up close to 40hp and a good bunch of Tq.Why are you so stinking rich even in the 12 range. I was running around 14.2 range and was safe and made the most power.
Anthony

well it's in the 12.9 range (my W/B) at WOT now and damn does it pull like a bitch.. it has never been able to bust them lose at 50 mph in 3rd till now so i'm leaving it till saturday (if it dont rain i'll hit the track)

log another car that was on the same dyno and his A/F was off 2.5pt also..Talked to the owner and he ordered a new W/B..


Bone there is NO WAY you were running WOT at 14.2 if so your a brave man :drink:

 

[GoatChs]

Although mine is a 408, currently running 10.2 AF (break in tune) and the tuner is expecting at least a 40rwhp increase with final tuning (including timing tweaks). And, yeah, I haven't heard of anyone intentionally running over 13.8 WOT and considering it "safe"...Bone's got skillz.