A 16cm housing will get you 2-3psi more than a 18.5 housing and 5-6psi than a 21cm housing.

Its easy to get 30+ psi out of a 89-91.4, 1st gen engine with stock inj's. Its a little harder but very possible to get 30+ psi out of a 91.5-93, 1st gen with stock inj's as long as the engine and pump is healthy.

 

Pulling a steep grade unloaded at WOT I can hit 28psi of boost. I have a 16cm housing, 4" exhaust and the pump is pretty much maxed with gov spring.

 

It's from a diesel engineering reference book I have and it's a "general rule of thumb" for design and application. Book is from the mid to late 80's so it should apply.
I've not taken any measurements to verify the statement. But we all know that elbows, length of piping, etc contribute to pressure losses in fluid transfer depending upon a lot of factors. I think that's more the point.
I have no intention of starting a "boost war".

Jay

 

Is Bully dogs 4 in exhaust from the turbo back?

 

I bought my governor spring at a place called Delco Diesel out of Ok. It was $16 that included shipping and tax. Yes it is worth it. The governor spring works good especially if you get an Old Smokey power pin.
My stock 92 has a 16 CM housing and the fuel screw in some and it gets about 23 PSI boost. Im at 4600 elevation.
Good luck

 

Frostie,
I notice you have a 6 speed, is that the nv5600, what did that set you back?

 

I can get 29-30 at wot, but also have pods, 16cm housing and 4" exhaust, and egt's are only about 1150* at wot, with the 18.5 cm housing, I could get 1450* easy and about 24-26 psi boost.

 

Wouldn' the boost loss across the IC be more closely tied to the cooling of the boost air and not a true "loss" as in leakage or whatever.... or did I just take a seniors nap here....

pb..

 

I think you're right on there, Bob. I'm sure there's some restriction at higher airflows, but I'd bet we "lose" more boost by cooling than because of a restriction.

 

That is correct. PV=nrT, where n & r are constants. So as temperature (T) goes down with volume being held the same (V), then pressure (P) is reduced.

It would be very interesting to run a pre & post cooler pressure and temperature guages . . .

 

Ya, you could put two fittings on the system and tie a big honkin balloon to each one,,, then you watch to see which balloon got the biggest...

pb..