Looking for opinions and input on exhaust housing sizes for the 250

[Corb@CorbinShipping]

OK, current setup

fuel- _110 Elite nozzles, Elite dual pumps, airdog 165
air- _HP non VFT 62mm double Batmowheel, .90 exhaust housing
_LP 75mm single Batmowheel, 1.30 exhaust housing
_Gated between stages, pushing the atmo
_6.0 manifolds, custom up pipes from Rudy's
_No Limit cold side pipe,


Last year, with no gate, this thing spooled like a rocket ship, and once moving, she cleaned up very nicely.... However.... The 62 was doing some serious work, around 30 Lbs (vs the 12-14 on the atmo) and 98-100 EBP...

Now, with our WG setup, at max boost, we are only seeing 50 boost, and 51-52 EBP, and spoolup is a good bit slower, and she is smoky...

Horse power (ignoring my dyno #s from this weekend... LOL) is way up from the 725 or so that she made last year, but I would like it to come on a bit sooner...

So, my question is, change the exhaust housing on the HP, the LP, or both, and what size would be recommended?

I also understand that this will likely mean running a second WG, as Shane and I have already spoken about it. If I could get the spoolup that we had last year, without the EBP hitting 100.... that would be sweet! As long as I could get the atmo working a bit harder.

What I was considering is this:
Only changing the Atmo (so as to see #s vs Change) and dropping down a small amount. Like going to a 1.10:1 housing as opposed to the 1.30:1 that it currently has in her. I think that would get it hitting a bit sooner, and not have retarded high EBPs... As long as spoolup is improved, smoke clears up a bit better, and EBP doesnt blow the heads apart, I am sure that will make me smile even more than I already am.

What do you guys think about that?

 

[Dzchey21]

So nothing changed on the high pressure between last year and this year other than now there is a gate?

 

[Dzchey21]

Spool up shouldn't have changed much if im reading correctly that nothing on the high pressure changed. The larger housing on the low pressure seams to be the reason your back pressure has dropped total. What I would personally do first is tighten down the gate to open later (unsure of where it's opening now I.would say in the 60 psi range of back pressure) or install roughly 1.2- 1.4 bar springs in the gate and let the spring pressure do all the work. If the thing spools better that's great if not then you need to downsize the Lp exhaust housing (which honestly the 62 should spool plenty fast no matter what)

Sounds to me like the gate is opening a little too fast... Without the truck in front of me tho it's hard telling.

 

[kyle43335]

i would do as above stated and put a 1.10 housing on the atmo.

 

[Corb@CorbinShipping]

Spool up shouldn't have changed much if im reading correctly that nothing on the high pressure changed. The larger housing on the low pressure seams to be the reason your back pressure has dropped total. What I would personally do first is tighten down the gate to open later (unsure of where it's opening now I.would say in the 60 psi range of back pressure) or install roughly 1.2- 1.4 bar springs in the gate and let the spring pressure do all the work. If the thing spools better that's great if not then you need to downsize the Lp exhaust housing (which honestly the 62 should spool plenty fast no matter what)

Sounds to me like the gate is opening a little too fast... Without the truck in front of me tho it's hard telling.

Correct, the only change, mechanically, is the addition of the gate. So EBP is def WAY under control, but spoolup is slow, but when it comes on, it is like a big single, and it slams you back in the seat pretty well.

Next question, how do I adjust the gate?

 

[Dzchey21]

Sounds to me almost like the gate is opening way too fast and almost bypassing the high pressure.

How is the gate set up? Full boost to the bottom? Regulated to the top?

 

[bigrpowr]

Make a bit more Bp ... It'll spool quicker and be just fine. Go for 55/65 prolly be an animal there.

 

[Corb@CorbinShipping]

So nothing changed on the high pressure between last year and this year other than now there is a gate?

Sounds to me almost like the gate is opening way too fast and almost bypassing the high pressure.

How is the gate set up? Full boost to the bottom? Regulated to the top?

ehhhh..... I have no idea. It is on the up pipe, leadin ginto the HP, then gated over to the LP

on take off, the BP shoots up to around 50, and levels off. It will hit 50, when the Boost is at 12-15, then at 40 the EBP is still around 50


We talking 1/4 turn and see what she does? or more than that? Less than that?

 

[forcefed6.4ford]

I think 1 full turn equals 0.5psi. THINK

 

[Dzchey21]

A full turn is more than that.

But do a full turn either way and see what happens big changes so you can figure out how it acts. After that small.changes. Also be careful the first time you hit it to be sure the back pressure doesn't shoot way too high

 

[forcefed6.4ford]

Write down your turn too so you don't get lost.

 

[madman1234509]

I agree with it being not properly adjusted. You shouldn't need to go to a smaller housing on that small of a low pressure turbo on that compound set up. There are guys running that same ratio or 1.32 on 80-90mm turbos. As stated sounds like it's possibly not driving your hp turbo hard enough down low.


Worse comes to worse, since you did have no gate before. Completely close off your gate ( to simulate it not being installed) . Drive it and see if it ran as it did before, then slowly adjust it to open a little at a time to get it to open where you want.

 

[Dzchey21]

I agree with it being not properly adjusted. You shouldn't need to go to a smaller housing on that small of a low pressure turbo on that compound set up. There are guys running that same ratio or 1.32 on 80-90mm turbos. As stated sounds like it's possibly not driving your hp turbo hard enough down low.


Worse comes to worse, since you did have no gate before. Completely close off your gate ( to simulate it not being installed) . Drive it and see if it ran as it did before, then slowly adjust it to open a little at a time to get it to open where you want.

I agree with you 100%

I agree it is a good idea to write all changes down and results of the changes

 

[Corb@CorbinShipping]

Cool. Thanks guys. 1 full turn, and I'll see what's happening.

 

[Corb@CorbinShipping]

Big Allen head bolt on top, center of Tial Wastegate, right?

 

[Dzchey21]

No there should be a manual regulator some where, take a picture of the gate if you can. where do the air lines run to?

 

[FaSSt9602]

Should look something similar to this:

 

[Motostroker]

Knowing Rudy he prob mounted next to the master cylinder. I agree with what they said. Fully close it to simulate no gate. Then open accordingly to find the sweet spot.

On a separate note, doesn't it sound like the problem mike@hallers was having with boomersoomer (I think that's his screen name) truck he built? Gate was opening up to quickly and dumping off drive psi?

 

[Motostroker]

Corb, here's a better understanding of the gate installed. I'm pretty sure he prob put this one on.

 

[Corb@CorbinShipping]

Holy chit, that thing is hard to turn... Is it supposed to be that tight? Is there a lock/release tab or something that I can't see? And in the middle of a bunch of crap too... I can't get my hands around the other crap back there, so I am gonna have to get something else to use. Small vice grip with rubber jaws so I dont mess it up.