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

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5speed

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Sounds good
Get hptuners and I’ll make you a tune to boost the low-end torque and response if you want. If you want more, consider LTH and F150 manifold. Otherwise you’re limited by the displacement.

 

DougS550

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So I ordered this;
Soler Prf. DLX Bluetooth Throttle Controller for $135.00 Shipped. If it smooths it out that will be good, and I already did the clutch spring but drive by wire throttles pretty much arent my thing.
I was always told Long tube headers are for top end, which is not what I want, I feel like it needs some shorty headers. Will have to research....
Let people know what you think of the Soler for I bought one and should have my car on the road in a couple of weeks. If it does what it says it will do then that would be great. Right now I don't want a $500+ Tuner and Tune and then have to contact tuner to make the changes I want day to day. When I go boosted, absolutely, but only because it's a necessity when building boost. Don't let the HP Tuner Only Cheerleaders change your mind on what you want for your car right now. Good Luck
 

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In regards to what ?
Power, and especially low-end torque.

I’ve spent a lot of effort measuring exhaust pressures. The collector backpressure increase due to the cat has never added up to much and it’s s basically nil at low rpm. I’m currently flowing 90 lb/min (15 psi boost) of air and the stock cat is only adding about 3 psi backpressure at 7000 rpm.
 

Basspro302

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Power, and especially low-end torque.

I’ve spent a lot of effort measuring exhaust pressures. The collector backpressure increase due to the cat has never added up to much and it’s s basically nil at low rpm. I’m currently flowing 90 lb/min (15 psi boost) of air and the stock cat is only adding about 3 psi backpressure at 7000 rpm.
So no dyno numbers?
 


WildHorse

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Really. Well I must have a unicorn cause I picked up .25 seconds after gutting the cats. Hence why I'm now building 3" head pipes for it.
 

engineermike

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The closer to the source you can measure something, the more accurate the assessment will be. Exhaust components add collector pressure. I have pressure data before and after the stock cats running 15 psi boost and they just aren’t adding much. Based on what I know about the stock engine flow rate, they’re adding less than 1 psi at the collector. I have dynod the effects of backpressure and once you get under 5 psi total, there isn’t much power left to gain. Oh, and that 1 psi i mentioned is at 7000+, so at the 3000 rpm range the OP is concerned with, the 1 psi turns to 1/4 psi. In total, the low-end effect will consist of more noise and gasoline smell.

I trust actual pressure data over quarter mile times because of the number of variables involved. In your track test, did you disable COT? Refill the fuel tank? Ensure identical weight? Identical atmospheric conditions? Disable FOASC? None of that matters when measuring exhaust pressure directly.
 

Basspro302

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The closer to the source you can measure something, the more accurate the assessment will be. Exhaust components add collector pressure. I have pressure data before and after the stock cats running 15 psi boost and they just aren’t adding much. Based on what I know about the stock engine flow rate, they’re adding less than 1 psi at the collector. I have dynod the effects of backpressure and once you get under 5 psi total, there isn’t much power left to gain. Oh, and that 1 psi i mentioned is at 7000+, so at the 3000 rpm range the OP is concerned with, the 1 psi turns to 1/4 psi. In total, the low-end effect will consist of more noise and gasoline smell.

I trust actual pressure data over quarter mile times because of the number of variables involved. In your track test, did you disable COT? Refill the fuel tank? Ensure identical weight? Identical atmospheric conditions? Disable FOASC? None of that matters when measuring exhaust pressure directly.
So how many psi equal what hp? So at 6500 a reduction of 1 psi = what gain in hp?
 

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I trust actual pressure data over quarter mile times because of the number of variables involved. In your track test, did you disable COT? Refill the fuel tank? Ensure identical weight? Identical atmospheric conditions? Disable FOASC? None of that matters when measuring exhaust pressure directly.
Consistent .25 faster. Full tank. Half tank. Hot ambient. Cold ambient. High humidity. Low humidity. .25 consistent is .25 consistent.
 

engineermike

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So how many psi equal what hp? So at 6500 a reduction of 1 psi = what gain in hp?
That's a big question. The answer is; it depends a number of factors. It helps power in 3 ways - 1) reduced pumping losses, 2) increased airflow, and 3) increased knock margin.

1. All combinations benefit from reduced pumping losses, but the power gains are on the order of 1 psi = 2 hp.

2. NA/centrif/turbo can benefit from increased airflow, but PD supercharged does not. I've dyno'd gains of 10 hp/1 psi on an NA setup running around 10 psi backpressure, but on the same combo gained nothing when dropping below 5 psi. The NA airflow benefits diminish once you get below 5 psi due to the minimal differential vs near-zero pressure in the intake port. The entire stock Mustang exhaust imposes barely over 5 psi at max power and much less in the mid-range.

3. Knock margin depends largely on how far from MBT you are and whether or not you're running against knock. At low rpm, the Coyote hasn't had time to feed in the knock advance so you're not against knock yet.

FWIW, if you remove the cats then COT is still active, as is FAOSC. If you tune it to disable COT then you'll definitely pick up power from that. You should also disable FAOSC because it uses rear O2 signal to offset the front O2's, so gutting the cats will affect the actual lambda and power.
 

Basspro302

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That's a big question. The answer is; it depends a number of factors. It helps power in 3 ways - 1) reduced pumping losses, 2) increased airflow, and 3) increased knock margin.

1. All combinations benefit from reduced pumping losses, but the power gains are on the order of 1 psi = 2 hp.

2. NA/centrif/turbo can benefit from increased airflow, but PD supercharged does not. I've dyno'd gains of 10 hp/1 psi on an NA setup running around 10 psi backpressure, but on the same combo gained nothing when dropping below 5 psi. The NA airflow benefits diminish once you get below 5 psi due to the minimal differential vs near-zero pressure in the intake port. The entire stock Mustang exhaust imposes barely over 5 psi at max power and much less in the mid-range.

3. Knock margin depends largely on how far from MBT you are and whether or not you're running against knock. At low rpm, the Coyote hasn't had time to feed in the knock advance so you're not against knock yet.

FWIW, if you remove the cats then COT is still active, as is FAOSC. If you tune it to disable COT then you'll definitely pick up power from that. You should also disable FAOSC because it uses rear O2 signal to offset the front O2's, so gutting the cats will affect the actual lambda and power.
Keeping it out of cot is a huge benefit, ive seen the new gt500 pick up 10-20 hp on delete pipes. But im assuming the cats are different than the 5.0 and already flow excellent.

Ive looked into adding gesi cats but they are extremely expensive.
 

WildHorse

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FWIW, if you remove the cats then COT is still active, as is FAOSC. If you tune it to disable COT then you'll definitely pick up power from that. You should also disable FAOSC because it uses rear O2 signal to offset the front O2's, so gutting the cats will affect the actual lambda and power.
AFAIK if you use rear o2 relocates the COT will never come on for the most part. But I'd be happy to be proven wrong in case I missed it in the logs.
 

engineermike

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The cat temp is calculated as a function of load, rpm, lambda, etc. The pcm doesn’t know the cats aren’t there and calculates the temp just the same. I’d urge you to log the cat temp and see how high it goes.

The gt500 exhaust temp is over the COT trigger point the moment you get to full boost, so I believe they go into COT very soon after going WOT. I would presume deleting cats and disabling COT would be worth it on those.
 

WildHorse

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I’d urge you to log the cat temp and see how high it goes
1100 celsius max IIRC.

Anyways my understanding is COT kicks in at 1.650f & o2 sensor protection at 1,700f. No way a gutted cat will get that hot unless you go WOT for a very long time.
 

engineermike

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1100 celsius max IIRC.

Anyways my understanding is COT kicks in at 1.650f & o2 sensor protection at 1,700f. No way a gutted cat will get that hot unless you go WOT for a very long time.
I’m not saying a gutted cat gets that hot. I’m saying the pcm calculates the temp assuming it’s there, and when the *calculated* temp exceeds 1650 then it goes into COT whether the temp (and cat) is real or not. With cats gutted the car will go into COT under the same conditions as it would have with cats. You have to change it in the tune if you want otherwise.
 

 
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