Engine/Transmission (1994 - 1998) How much boost is too much boost??

[FreeBMW]

The beast seems to be boosting quite high these days (cold temps) being my first winter with her can someone tell me if these are normal??? I know the EGT's are a bit high..... they wernt there for long.



How high can one safley go on a stock compressor with a 16 cm non wastegated housing???



see my other mods below.



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[Deezul1]

The HX35 turbo is efficient to about 35lbs boost and after that the excess pressures create stresses that arnt worth the meager amount of HP generated. Mine is making 40lbs and I wish it was a little less by 5lbs or so.

 

[Bob Wagner]

keep an eye on the head gasket too

 

[Trizae]

mines running 27lbs,,,,, all i have to support it is a spring kit and timing,,,,,,,,,, 27lbs feels pretty good to me

 

[MCummings]

backpressure is insane at that boost, with that turbo.



That's about the same as 70PSI with twins.



Merrick

 

[TxDieselKid]

Might want to watch those 50psi runs, as there are several 35's that have let go (huffed) around there. I can peg 50 psi of boost with ease on my 35, but try to back out of it at 45, and not go over that line.



Get's thrilling trying to watch the boost gauge and the road, while feathing the throttle at 45psi of boost.







Andrew

 

[nfox]

HX35 Boost

I saw 42psi of boost a couple of times on my hx35 when it was on my truck, that was with a stock camplate full forward and 370 diamond beeeeeeeeeeeeeessssssss!! Sounds like anything over 35psi you are creating alot of heat and high drive pressure. Maybe charlan will chime in on his experience with his hx35 and high boost.

 

[Doubleclutch]

Coffee hasn't hit yet, but...

With that kind of boost and EGT, the advice I'm hearing is that the turbo is making boost but holding the heat in because it's so far out of it's MAP. I'll bet Piers or DD or Andrew (and others, see above) can come up with a nice turbo that can keep the heat down, which is all the turbo is for anyway, isn't it?

Greg

 

[SOOT]

I can hit 33 PSI with my stock 35 (other than wastegate being diabled) Very many runs like that and you will huff that little 35. As said before it's efficient to 35 PSI after that it heats the air to much thus causing high EGT's

 

[DMC]

I have a question.



I have been trying to decide on some gauges and I am wondering how much of a range of boost pressure I need to be able to read. I don't ever plan on having more than 300 hp. I'm kind of leaning towards a 0-60 psi gauge but was wondering if a 0-30 or 0-40 psi gauge would do the trick.



It certainly looks like FreeBMW is going to be reaching for his wallet real soon at 1500 degrees on the pyro and 50 plus on the boost.



And suggestions would be appreciated.



Thanks



Don

 

[T. Baker]

Clayton, what RPM was that at?

 

[vssman]

50psi?!!! As already posted your way out of the efficiency range of an HX35. You can also make your 35 into a hybrid 40. High tech turbo has the kits - I recently did mine and really like it.



http://www.htturbo.com



I'm not affiliated with them in any way, other than being a happy customer.

 

[FreeBMW]

Originally posted by vssman

50psi?!!! As already posted your way out of the efficiency range of an HX35. You can also make your 35 into a hybrid 40. High tech turbo has the kits - I recently did mine and really like it.



http://www.htturbo.com



I'm not affiliated with them in any way, other than being a happy customer.

just emailed them... . thanks for the info.





Those boost levels were at around 2500rpm maybe a little more.





I normaly dont see EGTs past 1300 or boost past 38psi. Thats why i posted this thread to see how bad this was... .

 

[Forrest]

Love to see a picture out the back @ the same time.

 

[dpuckett]

DMC,

Go with at least a 40 psi guage. In my non intercooled 91, I can hit 36 psi on a cool morning, with stock injectors, and a mildly tweaked VE. 30 psi guages ought to be illegal on any Dodge diesel, esp if you intend to BOMB.



Daniel

 

[DMC]

Thanks Pucket: I thought the 30 would be a little low. I might consider the 60 now. I dont plan on going beyond 300 hp but you never can tell I might run into some money and make this truck into a bad a$$ show and go. I dont want to do the gauges but once.



Thanks Again



Don

 

[MCummings]

Originally posted by DMC

I dont want to do the gauges but once.

Might want to go digital if you want to do them only once. 300HP isn't going to need 40PSI, but a show-n-go truck will need a 70+PSI gauge.



If you want to go Analog, an EGT gauge won't need changed (with different HP levels). A boost gauge isn't too expensive, and is easy to replace.



Just my $. 02



Merrick

 

[Hammer]

50lbs out of a stock 35 with a 16,I'd say your living a charmed life. The Hx35 is way out of map at that range and all it is doing is heating the air and killing HP. Beware of the hybrid from HTT and your stock headgasket as it will not liive the same charmed life the HX has,trust me this we have already found out recently... ... ... Andy

 

[vssman]

Originally posted by Hammer

... Beware of the hybrid from HTT and your stock headgasket as it will not liive the same charmed life the HX has,trust me this we have already found out recently... ... ... Andy

Care to fill me in? Feel free to PM me if you'd rather not post it.



Thanks



Paul

 

[Hammer]

Paul. .

This was not a dig on HTT's hybrid rather a dig on the boost level and a stock head gasket,LOL. Proram and I just tossed his head gasket,even o-ringed,with the addition of a HTT Stage 3 to his twins setup. Part of the head gasket problem was installer error,but,the 95lbs of boost we seen did not help. The point I was trying to make was this,Knowing how well HTT's hybrid works and levels of boost screaming near 50lbs the head gasket will be next to go. Over boosting a HX35 to 50lbs,you may get away with this for a while,while over-boosting a stock head gasket you will not. HTT's hybrid may be one of the most underrated setups out there... ... . Andy



on edit. . Keep in mind though,the boost we seen when we tossed the head gasket was with a twins setup,but,I have seen the levels that can be attained with one of these in a single combo and yes the stock gasket will be in jeopardy with continuous abuse.