Sizing up the outlet on the turbo

[Buzadero]

Ok. If I'm seeking to get more flow through these motors, the limiter is obviously the choke-points as the air moves through the overall system, right?

I'm new to the whole turbo concept, having done all my wrenching on gas offroad vehicles my whole life. So bear with me.

Am I correct in thinking that the use of a larger diamter exhaust needs to ideally happen beginning at the back of the turbo housing? If I currently have a stock 1st gen turbo, can I get my hands on a replacement that uses a larger outlet?

Thanks

[flashgordon]

Ok. If I'm seeking to get more flow through these motors, the limiter is obviously the choke-points as the air moves through the overall system, right?

I'm new to the whole turbo concept, having done all my wrenching on gas offroad vehicles my whole life. So bear with me.

Am I correct in thinking that the use of a larger diamter exhaust needs to ideally happen beginning at the back of the turbo housing? If I currently have a stock 1st gen turbo, can I get my hands on a replacement that uses a larger outlet?

Thanks

A smaller turbine or ex housing would be much better as it would make the turbo respond much quicler.................Or are you taking about the exhaust housing were the exhaust pipe mounds?

What year is your truck?
the 1st gen have a 18-21cm exhaust housing..........For comparison.......the 2nt gen trucks had a 12cm housing and has a waste gate to keep the turbo from over spooling

Flash

[ford69557ci]

you are correct the key to making power with any engine is flow. there are several turbos that have a 4" outlet vs our stock 3". the most common ones are the holset hx 40 or the schwitzer s300 series. if you are wantin to build an all out high rpm pull motor something like a k-31 with a 1.10 ar ex housing is great and that puts you with a 5" outlet but requires alot of fuel and rpm to spool it

[Buzadero]

I guess I am talking about the exhaust housing.

Essentially, I'm trying to get a 4inch downpipe on with the least amount of restrictions. I'm currently away from home on one of my jobs. I've diligently ordered plenty of upstream gizmos (fuel pin, 3200 spring, Tubez by Timmy, etc), ordered an array of gauges, and a KDP retention kit. My assumption is to now get the back end breathing freely.

I called Rip Rook and was informed that to get his 4" downpipe installed, I'm looking at both a tight fit as well as a closer-tahn-desirable tolerance to the firewall. In my limited reasoning ability, I'm looking at the outlet on what has been correctly termed the "exhaust housing", and it is pretty obvious that it would probably be easier to get the 4" downpipe mated to it if it were already 4".

So, still keeping in mind that my knowledge of turbo operation and subtleties is just about nada, can someone give me some enlightenment on which direction to head next?

By the way, this truck has a manufacture date of 4/92, manual tranny.

[PToombs]

Tubez by Timmy

Now that's funny right there!

[ford69557ci]

well on in intercooled truck your goin to need some bigger injectors before your goin to spool a turbo with a 4" outlet. but the cheaper side of the turbo spectrum is goin to be a used hx40 the higher side is goin to be a s300 probly a 62-71 with a 14cm housing or a 62-65 with a 14 cm housing.

[Philip]

The 4" system from Stan's does not have problems with the firewall clearence. Here is a pic of my 4" downpipe. The only thing I had to do was move the trans cooler lines about 1" towards the engine for clearence.

[ford69557ci]

that fits vey good i dont see why with that kinda setup people say that a 5" wont clear without mods to the trans dipstick?

[Buzadero]

Perhaps I'm beginning to understand a little better. But, the turbo theory still is confusing to me.

So, if I get the 4inch downpipe from Stan's, it will probably fit? But, the current turbo needs to either be replaced with something that moves more airmass? Is this close?

Do I need a different turbo, or a different sized housing?

[Philip]

The 3" exhaust housing is a restriction. But you have to be in a higher HP band than you are right now. Steping up to the 4" system will get you by for a while. Going from a 3" system minus the muffler to Stan's 4" system was good for a 100 degree drop in EGT's.

Ford a 5" down pipe will not clear the frame/bell housing area. If the truck is 4X4 it will not clear the transfercase area eather. The only way would be to drop it straight down below the frame. Then it would still be tight.

Here is a pic of the clearence between the 4" pipe and the cross member by the engine.



Here is a pic of the clearence around the transfer case with the 4". On this pic you have the same amount of clearence between the inside of the frame rail also.

[ford69557ci]

i must have a wierd truck my 5" fits fine. i just took the little brace off that runs between the frame and crossmember. your 4" is as tight as my 5" thats crazy

[eyoung429]

Pics of that 5in are going to be required now ford69557ci. My 4in fits almost as tightly as the one posted above by Philip and mine is only a 2wd.

[MunK]

looking at mine.... a new cross-member would make room for a 5" ...what do you folks with 4" already think............sound reasoning?

NoRM

[ford69557ci]

you just give the floorboard a little tp witha hammer and take the little cross brace out and it fits good

[PToombs]

Yeah, you don't need that crossbrace. It only helps hold the torque of the Cummins.