i have all but decided to install a holset turbo off a 5.9 cummins on my 355, after i built the engine i was utterly unsatisfied with its performance, when i sat down and thought up the ideas its all seemed good in my head, but apparantley a 350 hp 1984 z28 just isnt enough to scare the living **** out of me.....so now im lookin to add some boost, ive allready decided if i do this to replace the 58cc heads for somthing alittle more boost freindly, ive been looking at some 76cc patriot aluminuim heads and a to be determined boost cam.......i have a tubing bender and my shop and think i can make the header, and since ill be pulling the engine i can put a oil return hole it while its out, and use an AN fitting off the oil presure guage hole to supply the oil, ive decided not to go with an intercooler due to the fact of my being lazy, and that id have to hack up the car and do a boat load of custom tubing bends to get it to fit, so for now, a big k&n cone filter on the turbo should suffice. now for the kickers, will it matter that: my turbo of choice has no waste gate, im running a carb and not FI.....im just trying to cover my bases and keep my $2500 long block from pushing the pistons out the oil pan, so all comments that can help me tune it are appreciated

i want to do the same setup but i got a holeset hx55 turbo will that work

With no waste gate, the only problem would be too much boost as that is what determines max boost other than actual size or output of the turbo. You could probably get a waste gate for $200 or less. I don't like the idea of no intercooler as the compressed air could easily get to 250 degrees or more which is just the greatest thing for detonation. It can and has been done with carburetors, I used to run one, but it seems to be a science that not a large number of people know about yet. Basically, it's just hard to get a good tune and may take some tweaking from time to time.

u can pickup an ebay wastegate for around 60-80 bucks.

deff do and intercooler it makes a good diff in power output

the hx35 u have what size housing does it have? t3 12cm housing?

You could try a turbo off a 03 -04 dodge I think the exhaust housing is a little smaller and would probably be sized a little better,plus they are cheap I have seen them go for around 300 bucks and it hasa wasteate on them,
Joe

The single HX35 from the 5.9's is to small.You will need 2 of them and transam360 the HX55 will go over 700 hp if you want it to.

Mike is right about the hx35 being too small as a single on a 355. Go twin hx35 or something like a single hx55/hx60.

Already been asked and answered

http://www.thirdgen.org/techboard/po...too-small.html (Holset HX35 too small for a mild 357?)


How fast do you have to go? 500BHP too small for you? Or do you need twins for up around 1000 BHP?
The HX55 larger wheel will flow enough for around 800-900 BHP.
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Which HX55? The HX55 comes with different wheels.

im still a little lost on how the hx35 can support nearly 500hp on my truck 5.9l 12v cummins, yet is insufficient for a 5.7l gasser?

They are available in a few different flavors (12-21cm2 housings) which will make or break the ammount of hp the hx35 is capable of. I am currently limiting my 12cm hx35 to 35-40psi (by pedaling) as the exhaust housing is much too restrictive and kills my EGTs and i dont even want to know what kind of drive pressure is behind it!

im just sayin, i have like 4 of em layin on the shelves of my shop (my loggin skidders have the same engine as a dodge truck).........if your sayin its not worth the time to install one and you can make 500 hp on one, then why in the world would anyone buy a supercharger kit?

thats what im confused about, they are capable of supporting decent numbers on a diesel, why would it be any different on a gasser?

My hx35 will be sitting on the shop floor pretty soon too, tossing it for a ht3b/s300 twins on my buildup this winter (going for a mild 1000hp on straight #2) and i wanted to hack it onto the 357 in my car just for a laugh

ive always figured boost is boost.........maybe somthing about the exhaust not flowing enough? idk

well, the hx35 starts shooting hot air around the mid 30s but will push alot more. The main problem with it is usually the commonly small 12cm housing, on a CTD the stock housing starts becomming an issue at relatively low hp levels (3-400hp) and its very common for guys to go with at least a 14cm housing to help lower the drive pressures/EGTs at these power levels.


Boost isnt just boost! boost is a measure of the restriction. What you want is the highest volume of air and as cold as possible (keeping the compressor within its map) with the least ammount of restriction in the intake plumbing/engine.

Also, another side note on the hx35. I have seen dyno sheets of a CTD with just some free pump tweaks lay down 380/790 @ 30psi but drop to 310/700 @ 38psi. Mid 30s is about all a stock hx35 will do before it starts to blow hot air, the 12cm hosing chokes it off and the drive pressures go through the roof.

The only thing useful I have is that an hy35 will spool at 3300 on a 2.8L nissan/datsun and a .60/.63 T3 spools at about 2500 on the same engine. Not my car, just what is considered common knowledge.


There's your answer.

my truck (12v 5.9 cummins) builds boost from 1krpm but wont actually light till almost 2krpm, then it takes right off!

It could use some AFC tuning as i can dump so much fuel in that it stalls the turbo and takes forever to light!

The HY35 will spool a fair bit faster than the HX35 since thats what it was designed to do. It was put on the early 2000 dodge/cummins w/auto trannys as a means of satisfying the tree huggers (quick spool, less transient emissions) but was very restrictive with its 9cm single port housing.

The HY35 is useless for anything except a 4banger *****!