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AFR too high; how much more fuel pressure is needed?

The PEFI muffler isnt THAT restrictive. My experience is the 3” viney fab needs about .7 grams more weight in daltons to turn same rpm as 2.5 td super quiet and precision trail is a smidge less than td super quiet, very very close. The problem is the tune! Posts about engine jobs followed by posts about out of whack afrs.High fuel pressure is a patch job to cover messed up tuning or some other issue with that sled. I dont care how well designed the dd muffler is, it does not flow more than a 3” straight through muffler or a straight pipe , it simply does not! There is an underlying problem there guaranteed
 

KnappAttack said:
Still makes no sense to me that it can possibly be that lean on that muffler, and needing that much fuel pressure. Something seems off in the tune to me. Hillbilly had the different D&D 2.5" muffler on that 280 tune at Dynotech when he was there as I remember, and no way it was as lean as you're seeing here. IMO the added fuel pressure is a band aid for a corrupt tune.
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Sorry for my nearly duplicate post haha, I was typing and you were posting but obviously I agree 100%………makes no sense
 
When I'm back from my trip w these guys I'll get tune re-flashed in that sled to see if it makes any difference.
When I talked to PEFI Monday this week, they looked up the VIN on this sled and verified it was flashed w Stage 3 in fall of 2017 at Speedwerx. They told me the last thing the download sequence does is check the flash to make sure it's not corrupt. They said if the flash was bad, the sled will not even start.
I don't know if that whole story is BS or not. The sled runs great and plug color and piston color looks good w my fiber camera.
Anyway, I'm not saying anyone is wrong. I'll just have to check it out once we're back.
Maybe the FPR gage is wrong? It is vented per KA. It's the one TD sent in the kit. About 1" round. IDK.
 
When I'm back from my trip w these guys I'll get tune re-flashed in that sled to see if it makes any difference.
Turboflash said:
When I talked to PEFI Monday this week, they looked up the VIN on this sled and verified it was flashed w Stage 3 in fall of 2017 at Speedwerx. They told me the last thing the download sequence does is check the flash to make sure it's not corrupt. They said if the flash was bad, the sled will not even start.
I don't know if that whole story is BS or not. The sled runs great and plug color and piston color looks good w my fiber camera.
Anyway, I'm not saying anyone is wrong. I'll just have to check it out once we're back.
Maybe the FPR gage is wrong? It is vented per KA. It's the one TD sent in the kit. About 1" round. IDK.
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Verify gauge accuracy with a known fuel pressure qauge teed in.
 
The fuel pressure number really doesn't matter. He had a static fuel pressure regulator prior (preset, non-adjustable), he added an adjustable regulator and adjusted it until his AFR numbers were in a safe area.

43.5 psi to 52 psi = 19.5% jump in fuel

AFR adjusted from 14:1 down to 11.8:1 would be a 18.6% change in AFR

Bottom line is this, datalogging is super important, look at using a tune that offers it. There are many of these sleds running into preignition or detonation, not necessarily just 1 company, fuel pumps slowly dying, bad fuel from the pump, etc etc etc. I've fixed motors from every major tune supplier, some were worse then others, didn't matter if they had knock detection or not because some guys just squeeze the trigger and ride and don't pay attention to the dash. All of them try to tout that they have the perfect tune and that's not true! Customers call daily and want 300 horsepower on pump gas and that won't happen without a splash of race gas or octane booster and with the intake air temps of the stock turbo, it won't happen on back to back or lengthy wide open runs either!
 
justinator said:
TD asks you what exhaust you are running but the tunes are not muffler specific. Same tune for 3" exhaust as 2.5". I asked them because I have the pefi muffler, td sq 2.5" and recently got a 3" viney fab. They recommend 48psi with key on with closed loop because that way the system is mostly pulling fuel rather than adding it and if the sensor or module fails you are safer if you happen to be running some wacky hardware. If you dont have adjustable regulator you are all still fine.The regulator was required for header before they had header specific tunes. Now that they have have header specific tunes you are only required to have big fuel pump for all header tunes....
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Justinator, this made my head perk up. Talked to Mike at TD this morning about it. They recommend running an adjustable FPR with their freer-flowing mufflers (like the 3" Intimidator, which is basically straight through). They also recommend running the FPR with the 3" Super Quiet (what I run on both of mine) because the flow with that muffler basically maxes out the stock regulator. Most importantly, Mike recommended running the adjustable FPR regardless because it's a fail-safe. If an O2 sensor fails and the closed loop tune stops working, and therefore stops adding fuel, and reverts to a non-closed loop tune, the risk of running lean increases--and you won't know it unless you're datalogging. So, while I wish we didn't have to run the adjustable FPR with the header tunes, there's no way I'm not going to. It's cheap insurance against a failed O2 sensor, running lean, and puking an engine.
 
the fpr is a must with the header tune and 3 inch exhaust , my a/f were in the high 12 with out the fpr, now running the fpr at 48 psi key on. my a/f r in the low 12 , I have now updated to the td waste gate and fine tuning with closed loop , this is a game changer which allows more boost and fine tuning all at your finger tips ,
 
snowcaine said:
Justinator, this made my head perk up. Talked to Mike at TD this morning about it. They recommend running an adjustable FPR with their freer-flowing mufflers (like the 3" Intimidator, which is basically straight through). They also recommend running the FPR with the 3" Super Quiet (what I run on both of mine) because the flow with that muffler basically maxes out the stock regulator. Most importantly, Mike recommended running the adjustable FPR regardless because it's a fail-safe. If an O2 sensor fails and the closed loop tune stops working, and therefore stops adding fuel, and reverts to a non-closed loop tune, the risk of running lean increases--and you won't know it unless you're datalogging. So, while I wish we didn't have to run the adjustable FPR with the header tunes, there's no way I'm not going to. It's cheap insurance against a failed O2 sensor, running lean, and puking an engine.
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Maybe they changed their requirements as they gained test and run time on the tunes but I have emails from last winter back and forth with Mike and while they recomended the adjustable fpr for the exact reasons I listed above, (safer afrs in the event of afr module/sensor failure not knowing exactly what hardware each sled may be running)it was not required for header specific tunes. Maybe with more run time and cold weather/ big mufflers they decided to require it. Ive decided to not run a header anyway so my tunes are fine with whatever muffler I choose......afrs are plenty safe even with 3" viney fab which has a noticably larger, higher flowing inlet bellow then their current offering in the 3"sq. The adjustable fpr is a nice add on anyway as you can fine tune and being adjustable it has some troubleshooting benefits right at your fingertips.
 
justinator said:
Maybe they changed their requirements as they gained test and run time on the tunes but I have emails from last winter back and forth with Mike and while they recomended the adjustable fpr for the exact reasons I listed above, (safer afrs in the event of afr module/sensor failure not knowing exactly what hardware each sled may be running)it was not required for header specific tunes. Maybe with more run time and cold weather/ big mufflers they decided to require it. Ive decided to not run a header anyway so my tunes are fine with whatever muffler I choose......afrs are plenty safe even with 3" viney fab which has a noticably larger, higher flowing inlet bellow then their current offering in the 3"sq. The adjustable fpr is a nice add on anyway as you can fine tune and being adjustable it has some troubleshooting benefits right at your fingertips.
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Bought my TD SQ 2.5” last spring which came with a free upgrade tune, from MS16 to MS17. I was told then that a high flow fuel pump and FPR was not needed for any muffler, even the 3”. But add the header and it would be needed!

The other way they put it was, anything over 290hp you needed it which is their claim for the 17 tune with 3”, CAI, 3 bar and BOV.

My tune should be around 285hp.
 
justinator said:
Maybe they changed their requirements as they gained test and run time on the tunes but I have emails from last winter back and forth with Mike and while they recomended the adjustable fpr for the exact reasons I listed above, (safer afrs in the event of afr module/sensor failure not knowing exactly what hardware each sled may be running)it was not required for header specific tunes. Maybe with more run time and cold weather/ big mufflers they decided to require it. Ive decided to not run a header anyway so my tunes are fine with whatever muffler I choose......afrs are plenty safe even with 3" viney fab which has a noticably larger, higher flowing inlet bellow then their current offering in the 3"sq. The adjustable fpr is a nice add on anyway as you can fine tune and being adjustable it has some troubleshooting benefits right at your fingertips.
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That’s what I took away from my conversation—they did some more testing/tuning and thought adding the fpr was the safer recommendation for header tunes. Props to Turbo Dynamics for continuing to invest the time and effort in perfecting their product. This is why I “sell” TD to everyone I meet on the trail. Good service and great products.
 
Back from 5 day trip. TCat I worked on went with. Sled ran great whole time.
Still going to get tune verified/re-flashed even though it ran good.
Ended up at 49-50 psi to maintain AFR at high 11's. Richest at WOT. Probably could tweak it down to low 12's with the good gas he's running. That might mean FP ends up sitting at 48, maybe even 47.
IMO cannot run stock FP on this tune w this muffler to keep AFR safe. Maybe with PEFI muffler would be ok?
Owner is happy we got to bottom of why motor got hurt (even though it took over 4 years to happen).
 
Turboflash said:
Back from 5 day trip. TCat I worked on went with. Sled ran great whole time.
Still going to get tune verified/re-flashed even though it ran good.
Ended up at 49-50 psi to maintain AFR at high 11's. Richest at WOT. Probably could tweak it down to low 12's with the good gas he's running. That might mean FP ends up sitting at 48, maybe even 47.
IMO cannot run stock FP on this tune w this muffler to keep AFR safe. Maybe with PEFI muffler would be ok?
Owner is happy we got to bottom of why motor got hurt (even though it took over 4 years to happen).
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The motor got hurt because of a crappy tune, no offense. These sleds don’t really lose power running rich, so it’s much safer to be closer to 11:1 vs 12:1
 
Turboflash said:
Back from 5 day trip. TCat I worked on went with. Sled ran great whole time.
Still going to get tune verified/re-flashed even though it ran good.
Ended up at 49-50 psi to maintain AFR at high 11's. Richest at WOT. Probably could tweak it down to low 12's with the good gas he's running. That might mean FP ends up sitting at 48, maybe even 47.
IMO cannot run stock FP on this tune w this muffler to keep AFR safe. Maybe with PEFI muffler would be ok?
Owner is happy we got to bottom of why motor got hurt (even though it took over 4 years to happen).
Click to expand...

Looks like Sebastien added some notes on the tunes. Dont recall seeing this earlier this winter.
CAC4589B-6FCC-4695-B68D-42C4B0033E6E.jpeg
 
ill give all you guys a strong piece of advice,,, change your fuel line if you are increasing pressure for any long runs.... the stock fuel line is a SIMPLE plastic shrink wrap over the quick connect with no clamp!! it is only 4" from ALOT of heat.... on a long haul that heat in that area will get up to 200+ deg and the fuel tube softens and next thing you know..... pop goes the line with the extra pressure.... and the rest is history when high octane fuel goes on the red hot turbo!!! either cover the tube with high heat wire loom or chaneg to a high presure fuel injction line from tank to fuel rail quick connect. trust me i know some are going to say "ive gone 4000 mile no issues" but ... it doesnt mean to say it still wont go. im just trying to save a life here. i tested my line ... put line in vice and used a heat gun a foot away and it took maybe 10 second while i pulled on the fitting with about 10lbs force and the fitting poped right off.

the other comment that i want to ask about was how did your increasing fuel pressure increase you afr at idle?? Knapp and i have had same issue, mine for some reason at idle runs 14 AFR, i cannot get it lower, but sled runs right on everywhere else with auto tune 13.7 low speed, 13.5 mid and wot 11.9 with FP @47
 
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