Max EBP before needing a wastegate

Newstroker · May 6, 2012

First off, I want to say hi since this is my first post and say I could not be happier to be in a 6.4!

I have a 2009 ford F350 with a few mods:
spartan tuner
dpf delete
egr delete - no wastegate
h11 studs
upgraded valve springs
upgraded pushrods
CAC pipe
Aftermarket downpipe
71mm towpower turbo
15% over tips
cai
ad165

On the 275 tune i am seeing around 83-84psi on the dd at wot on a long pull. When I roll into the throttle it will hit approx 76-78psi and continue to build. All psi readings are on the DD so it is 14.7 higher than gauge.

So I am wondering at what pressure should I install a gate? My boost pressure is approximately 58psi...I was mainly watching ebp. I will be drag racing and sled pulling on the weekends with this truck, and it is my daily driver.

Thank you,

Paul

forcefed6.4ford · May 6, 2012

I think most are gating around 60psi.

powerlifter405 · May 6, 2012

Contact Jeff direct for tuning advise. EBP should be 1:1 from what I see from WOP and others who began working on good setups for the 7.3 back in the day as the windowed 7.3 became staple for those not watching CP and EBP.
You should get plenty of internet bench racing ideas but you might be better served by calling a 6.4 engine builder to see what they say. Rudys would be the 1st off the top of my head to suggest calling/emailling.

Doing one sooner than later, would not hurt reliability.

Good luck.

Newstroker · May 6, 2012

Wow this site is great! I appreciate the information. I plan on calling spartan and rudys tomorrow morning. Rudys is where I got most of the my parts and they were great to deal with! I searched a decent bit before posting this and saw a lot of different figures about EBP...some said they tried to keep it 1:1 and other said like 10psi above their max boost.

Jeff@Spartan · May 6, 2012

Whatever you see on the DashDAQ is going to be back pressure + barometric pressure.

I see 66-69 psi max with my setup and I don't see the need for a wastegate. Even if I had a wastegate, I'd probably have it set to open around 68-70 psi of actual back pressure. The stock valvetrain can handle that much no problem.

Newstroker · May 6, 2012

SPARTAN said:
Whatever you see on the DashDAQ is going to be back pressure + barometric pressure.

I see 66-69 psi max with my setup and I don't see the need for a wastegate. Even if I had a wastegate, I'd probably have it set to open around 68-70 psi of actual back pressure. The stock valvetrain can handle that much no problem.

Jeff,

Thank you for chiming in! I think I will let it go and log EBP during a hook and a 1/4 mile run and see what happens. Do you know the limit of the stock ebp sensor?

I guess if I start pushing alot over 70psi of gauge EBP then I should start looking for a gate?

I have had issues with wastegate fouling on previous trucks and only want to put one on if I need to.

By the way, I love your tuning! I cannot wait to load up the 310 tune! I might wait till I build the trans though!

Paul

switchmode · May 6, 2012

He has upgraded valvesprings and pushrods so he doesn't have to be worried about valve float due to high backpressure. The one problem you could run into is overspeeding your turbos by driving them to hard and putting them out of their efficent range possible causing failure of a turbo or turbos.

mike@haller's · May 6, 2012

on stock fuel trucks usually a waste gate isnt needed like jeff is saying. Ive found every setup ive done so far that 71psi absolute back pressure seems to make the most power on the dyno, with no gains in power by going above that. (Some setups may be a little different) So 71psi is where i set most gates up to hold. The factory ebp sensor will only read 86psi absolute.

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Ipkyss · May 6, 2012

switchmode said:
He has upgraded valvesprings and pushrods so he doesn't have to be worried about valve float due to high backpressure. The one problem you could run into is overspeeding your turbos by driving them to hard and putting them out of their efficent range possible causing failure of a turbo or turbos.

That would be my biggest concern.

My next would be why your backpressure is almost 20lbs more than mine and Jeffs? Is it just from injectors? Thats enough to make me not touch mine right there.

switchmode · May 6, 2012

Exactly he is running the equivalent of 60hp nozzles.

Newstroker · May 6, 2012

I am not sure if Jeff was saying 66-69 gauge or absolute. I am thinking gauge... but I could just be trying to make myself feel better LOL.

I have a theory in addition to the injectors. What if my valve springs are also adding to the increased EBP? For instace say the stockers start to compress a bit (not enough to create problems) where mine are holding the exhaust valves fully shut. No clue, but throwing it out there as an idea.

Newstroker · May 6, 2012

Ipkyss said:
That would be my biggest concern.

My next would be why your backpressure is almost 20lbs more than mine and Jeffs? Is it just from injectors? Thats enough to make me not touch mine right there.

How much EBP are you seeing on your DD if I may ask?

forcefed6.4ford · May 6, 2012

72-75psi backpressure absolute or 59-62psi desired is ideal. You are a little high so you may want to think about getting a gate to lower it a bit. Not the end of the world.

Your pressures are higher because of the added fuel and larger atmosphere turbo.

78f100 · May 6, 2012

Good info here, I have a similar set up but stock springs with a wg. I am tring to figure out the best setup for my gate, I have never tuned one before.

Ipkyss · May 6, 2012

I am 1-1 at WOT with the Spartan 310. So 53 psi boost. 53.5 psi EBP+14 (67.5). The dashdaq will read both absolute and actual ebp. I believe the ebp sensor stops reading at 85.7 Atleast that is the highest reading I saw when I was having tune issues last year.

Does the 71 clean up the 15% injectors?

Newstroker · May 6, 2012

Ipkyss said:
I am 1-1 at WOT with the Spartan 310. So 53 psi boost. 53.5 psi EBP+14 (67.5). The dashdaq will read both absolute and actual ebp. I believe the ebp sensor stops reading at 85.7 Atleast that is the highest reading I saw when I was having tune issues last year.

Does the 71 clean up the 15% injectors?

The highest tune I have run is the 275EL and yes it cleans up great. It def rolls some coal down low but cleans it up pretty fast.

What tuning issue were you having if I may ask?

Thanks for your help!

Ipkyss · May 6, 2012

It was a cold weather issue with one of the old 310 tunes. I was seeing 85 psi ebp at 30 psi boost part throttle. I was one of only a few people that had the issue. It seems if there is an odd issue to have, my truck will have it :doh:

B585Ford · May 6, 2012

Does the Spartan DD/Phalanx allow you to set the defuel based on EBP? I know H&S can be set to defuel based on the boost, but not EBP.

B585Ford · May 6, 2012

Newstroker said:
I am not sure if Jeff was saying 66-69 gauge or absolute. I am thinking gauge... but I could just be trying to make myself feel better LOL.

I have a theory in addition to the injectors. What if my valve springs are also adding to the increased EBP? For instace say the stockers start to compress a bit (not enough to create problems) where mine are holding the exhaust valves fully shut. No clue, but throwing it out there as an idea.

That is an interesting question...I never really thought of it before...I'm interested to see what some of the experts think.