So lets talk AFR's

[TC]

So I got this App for my Ipod that is a HoneyWell Turbo selector. Basically the first screen asks you how much HP you want to make, how many Liters the motor is and if it is a single of twin turbo application. Then the next screen asks for fuel type, but this is where things get interesting, if I pick pump gas, it automatically sets the AFR's to 11.5:1 but if I select Race Gas it automatically sets the AFR's the 12.5:1.

So my question is, can running a richer AFR with pump gas give you the same detonation resistance that the higher octane of race fuel does??

[SpiderGearsMan]

go with iron
'
nobody can keep valve seats and guides in aluminum heads
seeing it on stock ecotec , 5 cylinder and 6 cylinder atlas engine , even an ls7 in a z06

brodix is having a hard time with guides

[TC]

go with iron
'
nobody can keep valve seats and guides in aluminum heads
seeing it on stock ecotec , 5 cylinder and 6 cylinder atlas engine , even an ls7 in a z06

brodix is having a hard time with guides

You know Spidey I think they are giving you way better drugs than I'm getting....... Dude AFR's, as in Air Fuel Ratio, NOT the AFR aluminum heads, your just being silly........

[A/Fuel]

You know Spidey I think they are giving you way better drugs than I'm getting....... Dude AFR's, as in Air Fuel Ratio, NOT the AFR aluminum heads, your just being silly........

And you have a turbo app for your Ipod? WTF?

Are you asking if you can prevent detonation by increasing the air fuel ratio? Sort of an intresting concept but since you are talking pump gas, I'd say no.
I don't think going from 11:1 - 12:1 is going to do that much on a gas engine except be rich. It might keep you busy on your Ipod at the grocery store though while you wife is taking the stuff out of the cart and putting it on the coveayer belt.

I applied that same concept to a nitro engine a few years ago, and when I poped the pistons out the rings looked like slinkies.

[TC]

And you have a turbo app for your Ipod? WTF?

Are you asking if you can prevent detonation by increasing the air fuel ratio? Sort of an intresting concept but since you are talking pump gas, I'd say no.
I don't think going from 11:1 - 12:1 is going to do that much on a gas engine except be rich. It might keep you busy on your Ipod at the grocery store though while you wife is taking the stuff out of the cart and putting it on the coveayer belt.

I applied that same concept to a nitro engine a few years ago, and when I poped the pistons out the rings looked like slinkies.

Ya it's called the Boost Adviser and it is put out by Garrett(Honeywell) for the Ipod/Iphone.........

Basically fill in the fields and it will recommend which Garrett Turbo(s) to use for your application........

As for the AFR's for Pump Gas and Race Gas, you just pick whichever and it fills in the fields for you, but what I don't get is why the pump gas AFR's are so much richer than the race gas AFR's........And are they trying to say you can make 1400hp with pump gas by running a richer fuel mixture.

I do see where a richer mixture would cool the intake charge more.............

[A/Fuel]

So it's a spread sheet?
I wish it was that easy!

[CDMBill]

This is the same situation as with any general guideline spreadsheet, application etc. They are going to give a safe tune and the recommendations that flow from that safe tune. Sounds like a fun app none the less. I went ahead and downloaded the calculator as my next project will be a large single turbo deal. The calculator allows you to adjust AFR's but does default to the settings you mentioned as it does for a number of things i'd to guess at anyway, intercooler efficiency and such. It say in the disclaimer that it looks at impeller sizing only not the inducer and says its only an guesstimate in so many words. Never the less its a good free what if tool. It said I can make 1502 HP at 10.50 PSI using a single GT6041, 141mm 1.05 A/R. Wheeeee! Changing to race gas only all other settings the same required 10.25 PSI. Kinda makes me want to get greedy with a bit more boost.

I have a buddy who worked at Garrett and built a 55 Chevy with a pretty mild aluminum headed 468 BBC. It looks like a show car and has run 10.33 at 135 on its first outing with the waste gates set at 9 PSI. He also just did the CC Anti Tour with almost no issues at all. Turbos rule. Dammit.

[TheSilverBuick]

So my question is, can running a richer AFR with pump gas give you the same detonation resistance that the higher octane of race fuel does??

Theory aside, unless I'm missing something, my experiences says yes. I've had a pinging issue in 5th gear running up the steep hills between Vegas and So. Cal. until this last trip. I richen the mixture up to 12.5 on the hill climbs and I don't hear any audible pinging now. That is to say, if detonation is occuring, I can't tell....

[dieselgeek]

From a tuner's perspective, I always run pump gas just as rich as we can get away with when turning up the boost, and most engines have around a 16-20psi limit on pump gas no matter how rich it is. That's usually in the mid 11s AFR.

IATs are a big concern on pump gas (inlet air temp) - 180 degrees is enough to provoke detonation, that's why lots of guys run supplemental methanol injection when they're trying to make big power on pump gas, or good intercoolers.

Another big problem with pump gas is inconsistency. You don't really know what you're getting when you top off with that 93 octane BP fuel, as compared to filling up with race fuel (whose quality is better controlled). I had customer who topped off with "mom and pop shop" gas and after his first WOT blast broke all 8 ringlands.

On better gas, we run leaner. Full boost on Gary Hart's studebaker (20psi) we'd run C16 fuel and couldn't run any richer than high 12s AFR without having misfire.

Hubers run C16, 40psi of manifold pressure, also has to run mid twelves or leaner. They've also had issues where C16 doesn't burn well if your intake temps are below 50 degrees F.

[SpiderGearsMan]

You know Spidey I think they are giving you way better drugs than I'm getting....... Dude AFR's, as in Air Fuel Ratio, NOT the AFR aluminum heads, your just being silly........

oops sorry , I just hopped on the title
I could have engineered a real slick answer off the google