24* of timing on an upper only???

[b_dike]

Ok so I finally made it out to "House of Boost" to have the car dyno'd, and found out that the tune loaded on the car is running 24* of timing on a 93oct tune. I don't have 93oct in my area so I've been using 91oct instead. Which is probably why my a/f ratio is 12.5.

Is this safe at all or is this a ticking time bomb. I've always been under the impression 21* of timing was the max you'd wanna run with pump gas on an upper only cobra.:??:

Any thoughts?

 

[oldmodman]

On 91 octane you might have to pull even more timing for a safe tune. Plus AF should be closer to 11.5 - 11.8
But an even more important question is how much boost are you running.
13 psi, you might be OK with 24 degrees.
17-18 psi, your are looking at a set of damaged pistons. Due to detonation and heat. Especially with an AF of 12.5

 

[Ironhand]

Typically unported upper only eatons are set at 23 degrees of timing on 93 octane
Ported eatons are usually around the 20-21 degree of timing on 93 octane.

With 91 octane then you would want to drop about 2 degrees of timing to be safe.

 

[snakerider]

typically unported upper only eatons are set at 23 degrees of timing on 93 octane
ported eatons are usually around the 20-21 degree of timing on 93 octane.

With 91 octane then you would want to drop about 2 degrees of timing to be safe.

+1 ^^^^^. We have 91 octane here in Cali.. My timing was set at 18 degrees for 91 octane. And 21-22 with 100 octane racetune.

 

[03_termi]

im on 21* with a ported eaton upper and lower at 15psi on 93 octane 11.8ish afr

 

[b_dike]

I have a 2.76 so the chart says I'm making 15.2 lbs, but real world conditions I think it's closer to 13lbs. So would that be ok or am I still in trouble here? The tech there said I could probably run 21* on 91oct and stil make the same amount of power, and ad a lil more fuel up top also.

Regaurdless I'm gonna have it dyno tuned so I don't have to worry about it.

Also I thought 501rwtq was pretty high for a upper only cobra. Any thoughts on that? Maybe because of the aggressive tune?

Thanks for the input guys.

 

[Ontariomystic]

12.5 A/F is not safe.

 

[66fastbackmusta]

Ok so I finally made it out to "House of Boost" to have the car dyno'd, and found out that the tune loaded on the car is running 24* of timing on a 93oct tune. I don't have 93oct in my area so I've been using 91oct instead. Which is probably why my a/f ratio is 12.5.

Is this safe at all or is this a ticking time bomb. I've always been under the impression 21* of timing was the max you'd wanna run with pump gas on an upper only cobra.:??:

Any thoughts?

This is a little worrisome. I live in Kansas City and was wanting to have my car re-tuned and was thinking of House of Boost. I might go by and talk to them tomorrow. I have way to much $$$ in my build to have a tuner that does not know what he is doing blow up my engine.

What are your thought about the tuner's knowledge?

 

[Emwun Garand]

Holy shit @ 12.5

I had my car dyno'ed by Manny Alvarez @ HPP, he knows his shit with these cars and he shut mine down when it hit 12.2 at WOT.

Somewhere in the 11's is where you want to be.

 

[b_dike]

The guys at house of Boost are NOT the ones who tuned my car. All they did is run it on the dyno. The tech that ran my car seamed very knowledgeable and I'm planning on returning to have my car dyno tuned by him personally.

Just to clear up any confusion regaurding "house of boost". They DID NOT tune my car. I bought this in April from a guy in Tulsa who claimed all work was done to the car before he bought it. All the H of B staff did is make me aware of the impending damage that could be done.

I still would highly recommend these guys to anyone, and especially if you own a terminator. The tech (can't remember his name) I worked with specializes in Fords and had tuned several 03/04 cobras.

 

[silver93]

yeah you sure dont want to be out making hard pulls on the car with that kind of a/f ratio. i bought my car and about 3 weeks later i fried all eight pistons in the car. so after about 3500 bucks later and thats me pulling and installing the engine i had it retuned at jms and the head tech there that dynoed my car said the tune that was in the car was more of a race gas tune not a pump gas so over time running it lean it eventully fried the pistons.

 

[01cobravortech]

I guarantee that 12.5 A/F number is not the real A/F. Tailpipe sniffer readings are never accurate. Weld 2 bungs into the midpipe before the cats and hook up a good, reputable wideband and I'm confident it will be lower than you think.

 

[01Jes]

I guarantee that 12.5 A/F number is not the real A/F. Tailpipe sniffer readings are never accurate. Weld 2 bungs into the midpipe before the cats and hook up a good, reputable wideband and I'm confident it will be lower than you think.

This is true^^^^

 

[b_dike]

Ok since there is no way I'd be able to weld anything any time soon. Is there another way to get a good accurate reading on my A/F ratio.

There is something else... Don't know if any of you have any experience with the SCT hand held. Because I may be able to patch the problem for now until I can get either bungs welded on or a retune.

I adjusted some options last night with my tuner. Chime-in if you know anything at all about this...

For my spark between 4k-8k rpm's I set to -3 (assuming the value of 0 is 24*) I should be at 21* correct?

For my WOT A/F I selected 2.0 richer (No idea how much or what measurement 2.0 is?)

 

[TVSCobra]

Get an Intercepter and wire in a wideband into it. When my diag failed on my BAP my interceptor and Wideband may have saved my engine. My car wasn't lean because I was on the edge without the BAP anyway but I saw my Fuel Pump Duty hit 98
% at WOT and my cruise was at 41%, I knew something was up. I usually run 30-33% FPDC at criuse and 70-74 at WOT. I played around with the BAP dail and saw the readings change on the interceptor. The rheostat on the BAP was faulty.

 

[Brutal Metal]

I guarantee that 12.5 A/F number is not the real A/F. Tailpipe sniffer readings are never accurate. Weld 2 bungs into the midpipe before the cats and hook up a good, reputable wideband and I'm confident it will be lower than you think.

The difference downstream with a tailpipe sniffer Versus bunged after the exhaust manifold WILL NOT bring a 12.5 down to an 11.5, the upstream reading will be closer to 12.2!

 

[01cobravortech]

The difference downstream with a tailpipe sniffer Versus bunged after the exhaust manifold WILL NOT bring a 12.5 down to an 11.5, the upstream reading will be closer to 12.2!

I don't believe I speculated the A/F would really be as low as 11.5 as that would be overly optimistic. I think under 12.0 though. In my own experience, I've had a tailpipe sniffer read a 12.4 and a wideband show 11.9. I've seen a guy report on ModularFords a while back that the tailpipe sniffer read .8 leaner than what the wideband setup read. I'm not saying we're going to see these kind of variances in every car but they are off some from what a tailpipe sniffer reports.

And that doesn't even factor in how often dyno owners change the 02 sensor on their reader. From what I've come to understand, some of these sensors are about $500 and need to be replaced after a certain number of dyno pulls because their accuracy is affected. So I mean theres a lot of things to consider when relying on a tailpipe sniffer to get an "accurate" reading. I would be curious to see what a good wideband would show hooked up to bungs before the cats.

And I also don't dismiss the good possibility that it is also as lean as you believe. Either way, I'm not a fan of verifying A/F by the dyno. I know you just can't weld on bungs that easily when we buy these cars but I think its a good "mod" to do on these cars for more accurate A/F readings as the setups become wilder and more dependant on very accurate A/F. And there are a lot of good tuners out there that can meet this demand.

 

[Brutal Metal]

FWIW our tailpipe sniffer never read .8 leaner than a bunged wideband!

 

[01cobravortech]

Well that's a good thing and sounds like you guys are running with the right equipment!

 

[Brutal Metal]

Oh yeah and it's monitored on a daily basis to be sure it's doing the job correctly.
My car was about .2 leaner on the tailpipe sniffer