2018 GT. What mods to make the Coyote crank out more torque down low?

[WildHorse]

calculates the temp

Well how far off can the 'calculated' be from actual ? I wouldn't think it'd be much considering the modern electronics, and calculations based on various parameters. I mean, the Apollo missions in the 60's did that and it was pretty accurate. Yay math !

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[GregO]

 

[engineermike]

@WildHorse I don’t think I’m explaining this very well. When the car is stock I believe the cat temp calculation to be very accurate. When the calculated temp gets over 1650 iirc then it goes in cat temp lambda control and richens it up to cool the cats. It also advances the timing because the knock threshold changes due to lambda. If you gut the cats and make no changes to the tune, the pcm has no way to immediately know the cats aren’t there and has no feedback mechanism other than lambda, so it will still go into COT. If it went into COT 5 seconds into wot stock then it will do exactly the same with gutted cats. You have to turn it off in the tune if you don’t want this to happen. Even once the pcm recognizes a cat efficiency fault it will still go into COT.

@GregO I have a pair of those in my shop right now, along with the bungs needed to install them and the hptuners pro feature set to log actual cat temp vs calculated. You see, while I believe the stock cat temp calc is accurate, I believe the Whipple cat temp model to be a SWAG. I’ve copied some stuff from the gt500 cat temp model into mine but really don’t know if it’s accurate. I don’t have transmitters for the thermocouples yet, so it’ll be a minute before I get log data. And besides, I’m currently using the pro feature set to log exhaust pressure before and after my cats and it only has 2 analog inputs.

 

[GregO]

I have a pair of those in my shop right now,

I wouldn’t expect anything less of you Engineermike !
The small details matter.

 

[WildHorse]

I don’t think I’m explaining this very well

Your explaining it very well. Now never mind stock, functional cats. With my gutted cats I look at my logs every time I do 1/8 mile or 1/4 mile runs. Never seen Lambda go below targeted. The COT hasn't been touched, which leads me to believe my cat temps never reach the threshold. With boosted apps all bets are off.

 

[engineermike]

Your explaining it very well. Now never mind stock, functional cats. With my gutted cats I look at my logs every time I do 1/8 mile or 1/4 mile runs. Never seen Lambda go below targeted. The COT hasn't been touched, which leads me to believe my cat temps never reach the threshold. With boosted apps all bets are off.

If you saw 1100 C in your log then it most certainly was in COT unless COT was disabled or limited in the tune.

 

[WildHorse]

If you saw 1100 C in your log then it most certainly was in COT unless COT was disabled or limited in the tune.

Then I'd see .70λ . I did not.

 

[engineermike]

Then I'd see .70λ . I did not.

So you say you saw 1100 c (>2000 deg f) in a log, and you also know that COT turns on at 1650 F. But you say it wasn’t in COT, and that it’s also not disabled in your tune. So which is it?

It doesn’t automatically go straight to .7 lambda when in COT. You have to log fuel source to know for sure, because it modulates lambda to achieve the target cat temp.

 

[WildHorse]

So you say you saw 1100 c (>2000 deg f) in a log, and you also know that COT turns on at 1650 F. But you say it wasn’t in COT, and that it’s also not disabled in your tune. So which is it?

It doesn’t automatically go straight to .7 lambda when in COT. You have to log fuel source to know for sure, because it modulates lambda to achieve the target cat temp.

Whoops 1100f. And ok you win. Congrats.

 

[engineermike]

Fresh backpressure data using stock cats:

Exhaust Pressure Testing | Page 11 | 2015+ S550 Mustang Forum (GT, EcoBoost, GT350, GT500, Bullitt, Mach 1) - Mustang6G.com

 

[5speed]

Back on the topic of torque down low is it possible to change the cams and get more low-end torque? I realize a supercharger would be a big help but I’m not ready to go that extreme at this point

 

[K4fxd]

You could put truck cams in it.

Mike has the best answer, gen 3 truck manifold and long tube headers.

 

[GregO]

Back on the topic of torque down low is it possible to change the cams and get more low-end torque? I realize a supercharger would be a big help but I’m not ready to go that extreme at this point

So you’ll entertain changing cams but not rear gears.

 

[5speed]

I would because I know how the gears affect the car and the overall ratio change.

 

[WildHorse]

K.. this whole thread is just stupid . Not a little stupid.. but like mind boggling stupid. Truck intake ? Now truck cams ? Jesus man just put a Cummins diesel in it and call it a decade.

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