427R air to fuel and timing question

[Grabber07']

Alright guys,

Trying to do some research for my buddy. Currently has a 08 427R with the stock Roushcharger, running a smaller pulley (7-8psi of boost), installed aftermarket heat exchanger, and 90mm CAI. Everything else is as it came from Roush...stock block.

He recently ran on a Dynapack dyno with a tuner thats relatively new to the tuning business and had his car dynotuned.

My buddy Pulled 405 RWHP (not sure about the TQ) 11.7 A/F and 28 Deg of timing

We are here in Oklahoma (where it can get HOT) Also 91 octane pump gas is the best we can get...some contains 10% ethenol.

My concern is with that much timing should he be concerned? Most supercharged guys I know are running around 9-10 psi and are in that 15-18 deg of timing range. On pump gas in the oklahoma heat, with a smaller eaton being drivin that hard...should he be worried? Should he be looking for another tuner?

I am no tuning expert here and I know some of you guys are very savy in the subject. Any help would be appreciated.

 

[Dex]

thats a shitload of timing!

 

[Grabber07']

Thats my concern as well.

 

[05yellowgt]

Sounds like that tuner won't be in business long tuning like that.

 

[Dex]

He better not go WOT. KABOOM!

 

[Grabber07']

This is what Im affraid of. What is an optimal timing range he should stay within? With such low boost levels (7-8psi as compared to most on here running higher psi) shouldnt he be able to run a little more timing than others that are in that 10psi+ range?

His A/R of 11.7 seems ok...but that timing does make me wonder what "could" happen.

My buddy said on their initial dyno pass "ROUSH's" tune was at 28*. I find that odd, but Roush tends to run on the rich side and 4psi stock.

Anybody else have anymore opinions?

 

[don_w]

I agree with the 15-18* range.

 

[Grabber07']

Thanks for your input Don.

Wondering if any tuners on here could chime in and give me a little insight to their opinion on the Roushcharger and timing.

 

[Tom]

sounds like he didnt have some of the wires hooked up right on the dyno.. i run 22 to 24 on my drag tune. but thats for running 10s i would never run that on the street. my reg tune has about 18

 

[PNR Welding]

Alright guys,

Trying to do some research for my buddy. Currently has a 08 427R with the stock Roushcharger, running a smaller pulley (7-8psi of boost), installed aftermarket heat exchanger, and 90mm CAI. Everything else is as it came from Roush...stock block.

He recently ran on a Dynapack dyno with a tuner thats relatively new to the tuning business and had his car dynotuned.

My buddy Pulled 405 RWHP (not sure about the TQ) 11.7 A/F and 28 Deg of timing

We are here in Oklahoma (where it can get HOT) Also 91 octane pump gas is the best we can get...some contains 10% ethenol.

My concern is with that much timing should he be concerned? Most supercharged guys I know are running around 9-10 psi and are in that 15-18 deg of timing range. On pump gas in the oklahoma heat, with a smaller eaton being drivin that hard...should he be worried? Should he be looking for another tuner?

I am no tuning expert here and I know some of you guys are very savy in the subject. Any help would be appreciated.

Thats even a little high for C16 fuel.

 

[Grabber07']

So with running 91 octane pump gas....in oklahoma heat, even with an aftermarket heat exchanger; running 28* of timing is not advised and should stick to that 18* give or take mark.

Whats going to happen to the motor possibly...if he continues to run 28* of timing?

KABOOM i take it?

 

[Dex]

surprised it hasnt blown already.

 

[Grabber07']

I sent him a link to this thread. He might chime in here and shed some light on the details.

 

[zBlack08_427R]

Ok.... Here are the facts....

A/F 11.7
Ambient Temp during tune 58 deg
Base timing 28 degs, with auto changes every 10 degrees in temp change
I think it is around 20 degree advanced at 90

I use only 100% real gas, 91 oct. With race tune using 104/105 octane

The stock Roush tune, that I looked at was running 28 degrees adv.... The timing didn't get changed, we played with it... but once the a/f was perfect.... we left it alone. Pulled it to 26 degrees, lost 10 hp, so we went back to 28, car screamed!!!

It hasn't blown up yet at WOT... it pulls hard, no unusual sounds. I think it got into the low 60's today.

Mods include: 2.57 pulley, Steeda CAI, O/R X-pipe (no cats), Afco dual pass heat exchanger and tune

Any thoughts? Comments? Insight? If your a tuner, I don't have a problem sending you a copy of the tune.... let you look at it!

 

[Grabber07']

Hmmm not familiar with the "Auto correct" on the timing. I assume it uses your knock sensors to adjust.

 

[zBlack08_427R]

It actually uses the temp sensor to adjust according to air temp....

I am not a tuner, but I understand the "basics"... have been a mechanic for years now......

Anyways, since there is less air to be pulled in at high temps, the timing is pulled to adjust so there will be no kaboom! If I remember right, every 10 degrees, it gets pulled 2 deg or something like that.... I think it was 8 degs by the time it hits 80, 10 degrees by 90......

I have heard that I should take the charge temp sensor? (or something like that) and move it to the charge tube.... I believe the MAF reads air temp also, I could be wrong... but I see no need to move the temp sensor.

 

[Dex]

Well I cant really comment since Im not a tuner but from what I've picked up from watching and reading I dont think your timing should be that high. Im at 23* on C16 and 16-17lbs of boost.

 

[Dex]

oh, and welcome to the forum

 

[zBlack08_427R]

Thanx for the welcome.....

 

[Grabber07']

Does everyone else also use this "auto correct" feature that adjusts with temperature in their tune? Im no tuner but have only heard of people giving me one timing figure. for example running 11.7 A/F at 18* of timing. I understand pulling of timing if the knock sensors are sensing detonation. But havent heard of a tuner manipulating timing to allow it to adjust itself "safetly" when air temperature increases or decreases.

Per the example above of having 28* at 55 degrees and adjusting 2 deg per 10 deg increase in air temp thus having only 20 deg at 90* temp.

Can anyone shed some light?