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Discussion Starter #1 (Edited)
people have been asking me a lot to do some basic tunes for silly things like EGR deletes, or whatever, so i've decided to create a robotic auto-tuning service that generates a bin based on your particular needs.

this should be good for people that aren't comfortable tuning their own cars.

here it is: http://fbodytech.com/autotune.html

the tunes generated are nothing special, just the dead basic tunes to make your car run right. it's likely paying for a tune-by-mail tune may gain you a bit of performance over these, and for cammed out hopped up nos monster track queens, they definitely are not the tune you're looking for.

.. but that's what you get for zero dollars, so enjoy.

i will add more tuning options in my free time or as requested.
 

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This is cool. Keep em coming. I know the Auto shift points make a big difference.
 

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Discussion Starter #4
someone teach me about improving shift points and line pressure on a stock-ish car, and i'll do it, then. i know nothing about automatic tuning.

this is getting scrapped anyway.

i have a better plan in store:devil:
 

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Discussion Starter #8
if anyone has some decent proven shift tables they can donate from a fairly stock-ish car, and maybe some for a mild torque converter upgrades, or any tips on that, i'm all ears.
 

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Discussion Starter #9
other requests for tuning features will also be entertained (more is planned, injector sizing, maybe a few alternate timing tables...)
 

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Awesome job Steveo. Keep up the great work.
 

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I tuned my car shift points based on my own tire size, gear ratio, and speed. So basically I used a gearing calculator, figuresd out at what speed I'm at my desired rpm, and shifted about 3mph sooner than the table said. So of I'm at 6100rpm at 70mph in 2nd, I'll shift at 67. It's proven right so far. If I hit the limiter, I back it off 1 mph. If I don't I try moving closer. It's trial and error.

There may be better ways but I was comfortable doing it this way.
 

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Discussion Starter #12
that makes sense. it seems shift points are a bit mathematical based on gear ratio or whatever, since they're vs. mph. i think if i had a few examples of tunes that work well; i could probably extrapolate a safe formula to tune transmission settings across the board so they're "a bit better" which is all im aiming for with this tool.
 

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If you want I'll post up my current tune. I've been working on it recently and the car has responded pretty well considering the time I ran for bolt ons with stock 3.23's.
 

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Someone requested my latest tune so I'll post it here as I couldn't figure out how to attach it to a PM.

Here's my latest tune.

LE2 Heads
355 LT1
Stock Intake Manifold
Stock Throttle Body
1-3/4" LT Headers
3" ORY
! Emissions
3" Magnaflow Catback w/2.75" over axle pipe
Lunati 230/238 @0.050" (284/288 @ .006") 110+6 LSA .565/.565 Lift
1.6: Harland Sharp RR
K&N CAI w/ homemade elbow
255 Fuel Pump
36# Injectors
Stock Fuel Pressure
 

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i bet you have a lot of power left on the table there; have you checked your AFR with a wideband?
AFR is 12.2 to 12.9.

What makes you say that? Just curious.

I know my exhaust is pretty restrictive (a single 2.75" pipe over the axle is a hell of a choke point for my car). And my TB and Intake Manifold are untouched. But where in the tune do you see potential for more. I'm all for making more power!:devil:
 

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Discussion Starter #18
What makes you say that? Just curious.
your timing map is bone stock where it matters (heavy load, wot.)

for that kind of cam, WOT timing should look way different than a stock cam ...

AFR is 12.2 to 12.9.
max power on fast burning aluminum heads like this is found more high 12s to low 13s. you should head a bit leaner and see how it behaves.

a single 2.75" pipe over the axle is a hell of a choke point for my car
why is that? you're only 1/4" under a 3" exhaust. a single 2.75" isn't actually that bad for this kind of car, in fact it can promote velocity of exhaust gasses within the operating range of the engine to create more useable power in normal driving ranges. it might choke it out at very high rpm, but not much.
 

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your timing map is bone stock where it matters (heavy load, wot.)

for that kind of cam, WOT timing should look way different than a stock cam ...
This is what the build liked. As you can see this is the 16th Tune file for my car, and each file has been adjusted multiple times. I've done less timing and more timing. This is where it ended up. It is close to stock, but it's where it ended up. My dyno tuner isn't what I would call well versed on LT1's. LOL.



steveo said:
max power on fast burning aluminum heads like this is found more high 12s to low 13s. you should head a bit leaner and see how it behaves.
It could use a little more leaning out. But, at 12.9:1 AFR at max VE and a little richer down low I'm o.k with it. Here's my last dyno chart. The AFR line is at the bottom and peaks at 12.9:1 at about 5400RPMs.

I did find a place 5 minutes from my house that will rent me their Mustang Dyno for $100/hr. But, I want to get some other mods (like the exhaust) done before I dyno tune it again. I can play with AFR and Spark timing (I want to play with injector timing too) more then.



steveo said:
why is that? you're only 1/4" under a 3" exhaust. a single 2.75" isn't actually that bad for this kind of car, in fact it can promote velocity of exhaust gasses within the operating range of the engine to create more useable power in normal driving ranges. it might choke it out at very high rpm, but not much.
I understand exhaust gas velocities, but at my power level a 2.75" pipe (and a single 3") is a pretty good restriction to power. Optimally I should be at about 3.5" single at my dyno powered. But, that will go up as I open the exhaust. And it'll rise more with future mods too.

The further away from the engine the smaller the pipes need to be due to cooling, but with my engine VE exceeding 100% and pushing 6600 rpm (going to be 7K in the future) the math shows the 2.75" diameter over axle pipe is too small. And to that you should never reduce exhaust size down stream as it introduces a restriction. Even if it's set up to go from 3" to 3.5" to 3" again it's losing power. Once the exhaust pipe goes to a certain size it should stay there or get bigger only, never smaller.

Here the math. A straight pipe will flow ~115 CFM per square inch of cross-sectional flow area.

At 6100 my VE table is maxed out in the tune (tuner pro RT won't let me go any higher than 99.61%) and my AFR is ~12.5:1. Extrapolating the data from my PE AFR correction tables and the data log AFR on the dyno chart I can conclude that at 6100 RPMs my engine is at 106% VE.

At 6100 RPMs and 106% VE the engine is pulling in 664CFM of cool air, but pushing out about 970CFM of burned air and fuel. I need 115CFM per square inch of cross sectional straight pipe to match my 970CFM of exhaust gases. Of course the pipes are not straight, but it doesn't have to be perfect just close. It is a DD after all. My engine at 6100RPMs needs a 3.40" diameter single pipe exhaust, straight (using .060" for wall thickness). At 7K (assuming 100% VE, a 6% drop from 6100RPMs) I need a 3.53" diameter exhaust, straight piped. In either case they are both about 3.5".

At lower RPMs I will lose some scavenging, but it actually won't be too noticeable from where I am at now due to my LT headers and Y-Pipe and VE chart. To that point, my VE tables at my cruising speeds are ~50%, that would mean that optimally a single straight 1.5" exhaust pipe is optimal. I'm well over that, going even larger will have nil an effect at those engine speeds from where I currently sit.

This is all taking into account my engine as it sits. The TB will get done along with the Intake in time. The exhaust right now is about 65% the size it should be, so it's a restriction and a pretty good one at that. My current exhaust flows a max of 624CFM before it represents a restriction (and that's straight with no bends), I need 970CFM or 55% more cross-sectional area.

Most guys go with 2.2CFM per HP and 115CFM per sq inch of exhaust pipe cross section. That's 2.2CFM per flywheel horsepower. That puts me at about 1071CFM needed or just over 3.5" diameter single straight pipe as I sit.

No matter how I cut the math it points to a single 3.5" pipe straight (or 3/4" larger than where I am now). Remember that area grows at double the rate than diameter when it comes to a circles. Doubling the diameter will quadruple the area. The 3.5" exhaust is 27% larger in diameter, but 65% larger in cross-sectional area. A 3" diameter exhaust is only 1/4" (9%) larger than 2.75", but it's 20% larger in cross-sectional area. These numbers seem slightly off because I'm accounting for the .060" wall thickness.

Taking all that into account I've decided to shoot for a 4" Single exhaust with dual bullet mufflers (in series one on the I pipe and one right before the exhaust tip). That should support about 525rwhp without any losses in power, keep the exhaust tone low and at a decent dbl and like running Open headers.

That lets me upgrade the TB and intake manifold and still have room for some juice down the road with out ever having to change my exhaust again. And in the interim it wont effect driveability noticeably either.
 

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Discussion Starter #20
i understand the numbers and how they always push towards giant pipes, but in practice, i think you'll notice very little gain from going larger than 3" exhaust in that ~500hp range.

i betcha if you ran open headers right now with your 'restrictive' 2.75" pipe you'd gain like 8rwhp.

exhaust cfm is one area where the "ideal" math and reality don't quite match well.

guys with cutouts in front of a decent 3" system without a lot of muffler on it have proven that, the gain isn't gigantic.

i've also never heard a 4" single exhaust system with a gas engine sound very good.

not trying to talk you out of it specifically, just don't see the need to go bigger than 3". i dont think your numbers reflect an exhaust system that's robbing you of any power.

It could use a little more leaning out. But, at 12.9:1 AFR at max VE and a little richer down low I'm o.k with it. Here's my last dyno chart. The AFR line is at the bottom and peaks at 12.9:1 at about 5400RPMs.
if it likes that AFR, definitely keep it, especially if it's a street car. safe is good. the difference between ~12.9 and ~13.2 for example is fairly small.

i was about to ask how the hell you ended up at that AFR, but then i realized you're running speed density, so never mind.

This is what the build liked. As you can see this is the 16th Tune file for my car, and each file has been adjusted multiple times. I've done less timing and more timing. This is where it ended up. It is close to stock, but it's where it ended up. My dyno tuner isn't what I would call well versed on LT1's. LOL.
i'd be interested to see what he tried, and why it failed. it's by far the weakest spark table for a cam that size on an lt1 i've ever seen, it's 99% stock.

im also suprised driveability doesn't suck in a lot of areas with a timing map like that. if it's driving good, awesome. most people don't get that lucky.

keep in mind that with a stock cam, the two left hand columns are decel, the next couple are cruising on a flat road. with your cam, the first six columns of your timing map are likely just decel.

the stock timing table is set up for a cam that makes a realistic torque peak of like 2 grand and makes a ton of vacuum, and likes a whole lot of timing at very low rpm cruising range.

your setup is so far off of that. this is not something that will show up on a dyno or matter for a track car, where pretty much only the right hand two columns of the spark table are used, but more so with street tuning and aiming for 'smoothness'.

(I want to play with injector timing too)
now that's something i've never had the chance to play around with, with a cam that size where it'd make much difference. i'd be very interested to see what you come up with for sure; i bet there's quite a bit to be gained.
 
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