14 on3 twin turbo dyno graphs - valve float?

[InTrikit 5.0]

So I finally got my car running and tuned on on3 TT kit. Car is showing major power loss after 6800rpm. Looking for some thoughts….tuner says possible valve float or restriction of stock mani??
Mods.
14 Mustang GT
On3 tt kit 60mm bb turbos
Tial gates 5.8psi springs controlled by ebc
Return fuel system id1000 & twin hellcat pumps
Catless xpipe, resonator delete, Corsa extreme.
OPG & crank sprocket.
Stock heads/internals
https://photos.app.goo.gl/v6VHFFifohJvUzGz9

 

[Riddick]

Kevin is very knowledgeable, I would definitely listen to him on what he thinks the issue is.

The power does seem to drop off rather quickly, even if you are running the stock IM. Here are the first things that come to mind I would look into:
What was your boost doing when power dropped. Did it hold 5.8psi all the way up?

Any knock or fueling issues, what kind of timing are you running? Im assuming Kevin already ruled this out but just throwing it out there.

I dont think your having a valve spring issue at this power/boost level. What size exhaust housings are you running? If they are small it could be a restriction causing a power loss.

 

[InTrikit 5.0]

The power drop was barely there in the 5-6 psi range. It starts to occur above 9psi. The 600whp is 9psi.. The graph with the largest drop was just under 12 psi. Fueling, afr, and boost stayed flat. The link has boost logged. They are supposed to be .96ar. Wondering now if on3 shipped me wrong hotside…they have .68ar option. Although I think it would spool sooner if that was the case…


Correction- I found photos of when I got the hotside ceramic coated. Hotside is .68ar

 

[gimmie11s]

"Stock" manifolds? I thought On3 used their own manifold. If it is the same ones i had on my '14 TT on3 car several years ago, those flow just fine. I'd rule that out.

What about the rest of the exhaust after the turbos... What size piping?

 

[InTrikit 5.0]

"Stock" manifolds? I thought On3 used their own manifold. If it is the same ones i had on my '14 TT on3 car several years ago, those flow just fine. I'd rule that out.

What about the rest of the exhaust after the turbos... What size piping?

Sorry should have been more clear. Manifold meaning stock intake manifold. I have the upgraded cast turbo manifolds from on3. I have all 3” after turbo. Catless xpipe, lth ota pipes, Corsa extremes axle back.

 

[gimmie11s]

The x pipe "could" be a problem.

I also had what i thought was valve float on my 2018 TT car at bout 8 psi and was running an x pipe but with stock mufflers.

I removed the x, installed true dual 3" pipes into 3" magnaflow straight through mufflers and now can hit 14psi no problem at all.

What are the hot sides on your turbos? .82?

 

[InTrikit 5.0]

I did change to the magnaflow straight through axle backs thinking it might have been the Corsa extremes. I guess I could try an h pipe.

The turbos are .68ar

 

[gimmie11s]

That's a problem... Need to go .82's or larger for sure.

 

[InTrikit 5.0]

That's a problem... Need to go .82's or larger for sure.

I thought so too until I browsed through install pics of the on3 kit and found they are all .68 AR. You can find it stamped on the hotside. You wouldn’t happen to have old pics of the hotside from your on3 kit would you??? Lol. I’m still contemplating changing the turbos though.

 

[gimmie11s]

I thought so too until I browsed through install pics of the on3 kit and found they are all .68 AR. You can find it stamped on the hotside. You wouldn’t happen to have old pics of the hotside from your on3 kit would you??? Lol. I’m still contemplating changing the turbos though.

Im sure i do.. i'll have to dig them up but im darn near certain they were .82's. I'll see what i can find.

 

[Riddick]

Based on what your posting above you have a back pressure problem. As stated above you can try to free up your exhaust which may help a little. The main issue is your exhaust housings arent flowing near enough.

For testing purposes take off your exhaust and see if it improves.

 

[GNBRETT]

Its not gonna valve float at 6 psi. They start floating at 15 psi. I experience tons of back pressure without an electric dump. I also opt for the biggest waste gate I can get (66mm) as that helps with back pressure as well.

U sure ur 2nd fuel pump is working properly when activated? I had a similar issue on the dyno last year and my 3rd fuel pump was failing at the higher RPM's and had to abort. That was at 19psi. I have a FORE triples.

 

[gimmie11s]

Its not gonna valve float at 6 psi. They start floating at 15 psi. I experience tons of back pressure without an electric dump. I also opt for the biggest waste gate I can get (66mm) as that helps with back pressure as well.

U sure ur 2nd fuel pump is working properly when activated? I had a similar issue on the dyno last year and my 3rd fuel pump was failing at the higher RPM's and had to abort. That was at 19psi. I have a FORE triples.View attachment 1711855

Not at all apples to apples brotha. CPR kits far and away flow the best on the exhaust side of just about any coyote turbo kit.

He has a hot side problem that starts with those small turbine housings.

 

[InTrikit 5.0]

Its not gonna valve float at 6 psi. They start floating at 15 psi. I experience tons of back pressure without an electric dump. I also opt for the biggest waste gate I can get (66mm) as that helps with back pressure as well.

U sure ur 2nd fuel pump is working properly when activated? I had a similar issue on the dyno last year and my 3rd fuel pump was failing at the higher RPM's and had to abort. That was at 19psi. I have a FORE triples.View attachment 1711855

The problem starts to appear above 9psi. I’ve thought about adding electric cutouts before the xpipe and try that.
My dual pumps are always on I’m not running a pressure switch for the 2nd. AFR seems unaffected when the power loss occurs


Who tuned your car at shopct?
I used to bring my subarus up there back in the day

 

[GNBRETT]

I had PBD tune it a while back but I have a new combo now thats almost done and Lund will tune it. U should see "The Shop" now! Freaking place has like 5 dyno's there now it crazy how big they have grown.

They since moved to Stratford tho. Much bigger place.

The problem starts to appear above 9psi. I’ve thought about adding electric cutouts before the xpipe and try that.
My dual pumps are always on I’m not running a pressure switch for the 2nd. AFR seems unaffected when the power loss occurs


Who tuned your car at shopct?
I used to bring my subarus up there back in the day