hx40w

[beastberetta]

is a hx40w with a 19cm housing is that too big for my stock 3500? i need to know like asap before i buy it ;p;/

[timg]

If you look here, http://www.squirrelpf.com/turbocalc/ It's actually a good match for a 3.5L engine.
However, it also depends on what you want. If you don't mind some lag and are looking for good power, that turbo should work well. If you want boost by 2000 rpm, it's the wrong choice. Sounds like this turbo is a bit bigger than a GT35R. Smaller turbos make more boost and power at lower RPM, but that's at the expense of efficiency and power at the high end.

Tim

[beastberetta]

I am looking for some lag simply because i am on a stock 4t60e nd I dont want like instant boost nd hook up. I dont wanna break the trans in my first week having the car boosted lol. thank you for responding timg that was very helpful.

Now question what kinda numbers can I put down with a 3500 through an auto on 7 lbs? Nd than on 12lbs. I have 42.5s also nd itll be open downpipe no exhaust for a few weeks.

[timg]

At 7 lbs expect to add roughly 50% whp compared with your current dyno results. I feel the same way about these FWD GM platforms. Small quick spooling turbos are nice, but they do nothing to help traction. The one problem with large turbos is that they make a lot more power at your shift points and tend to wear clutches and bands if you keep the throttle pinned during shifts.

Tim

[beastberetta]

yea small quick spooling are very nice but when you dont want to break a trans a bigger turbo is fine lol...

what about a hx35w with a 12cm housing? i know alot smaller so itll be quick spooling but will it be efficient? nd no i plan on letting off as it shifts lol. until i get a built trans. any recommendations on a built trans?

[Driver_10]

You sent me a text, and everytime I went to answer it something would distract me. (phonecall, traffic, business phone starts ring etc.)

An HX40 is a bit of a monster for an otherwise stock motor. A HX35 8-blade (referred to sometimes as the poor mans GT35) would be an excellent turbo.

[beastberetta]

I actually settled on a 7 blade hx35 with a 12cm exhaust housing. Idk if I should upgrade the exhauat housing to the 14cm or the 16cm housing.

[ForcedFirebird]

The HX35 is a 500hp turbo, we have installed a few on 2.5l and 2.7l BMW engines and they have no problem spooling fairly quick (~2500rpm) and made 357WHP@15psi in the race car (7blade HX35-12). They are designed for diesel engines that spin half the RPM's and reflect that when put on petrol engines. Another local here has ah HX40 on his SOHC 3.5l BMW engine and it spools just as fast and is making 575whp/600wtq at 25psi.

Whatever you do, DON'T use the internal WG that comes with the HX35wg, it is set to 40psi and is too small to keep boost levels down. We popped a head gasket last year on a long track since the boost crept up to 21psi, and we were only tuned for 15 (36lb/hr injectors). Once we put a larger gate on it, we can drop the boost to whatever level we desire, on down to the WG spring setting (8psi).

[beastberetta]

i am actually having my uncle weld the wastegate flapper shut im running a external xs power wastegate with a 8.7lb spring in it. i was told it was fine dsm guys are running 20 lbs plus with the flapper welded shut so i should be ok on 7 lbs maybe 12psi max with a good tune. i do have a couple more questions...

stock mass air flow sensor, lt1 fbody maf sensor 3.5", or lq4 4" maf sensor for my turbo 3500 build. i need to know. i have a stock one and a lq4 right now. any input?

nd stock 3500 map sensor is it a 2 bar? or should i use my stock 3100 map sensor?

[timg]

Stock PCM's and MAP sensors are only 1 bar. Running 2 or 3 bar is possible, but those who have tried it before on a non-L67 setup have found the PCM reacts funny to seeing boost. You may be better off keeping the PCM in the dark in terms of the MAP sensor. For MAF, starting your tune with the stock MAF is easier, but you can use whatever you want. I would try to keep the diameter of the MAF similar to the piping before and after it. Having a large change at the MAF makes it read inconsistently. I've run a stock MAF and have a LQ4. If I do a Northstar TB swap, I'll go LQ4. Otherwise, the stock one fits better.

Tim

[ForcedFirebird]

We never welded the WG's shut, but rather take the flapper arm and use a piece of rod to bolt it solid to the housing. This not only allows the turbo to be re-used on another project later, it also secures the flapper without the risk of it coming lose. We have run them up to 15psi in this configuration without issues. I have welded cast iron before, but it's not only difficult, the welds like to crack after several heat cycles depending on the filler used.

[beastberetta]

ok so im going to use my stock maf with a 3500 map sensor any one know what bar the 3500 map is? ill be using 3" intercooler piping before and after the maf. im running a lx5 tb. i thought about using a lt1 fbody maf it is 3.5" so itll give my tuner more room to work with. i dont want to max out the stock maf. id rather be safe than sorry.

nd for the turbo. my uncle got creative i guess. he threaded the arm nd put a bolt in there and than cut off the top and grinded it down to make it flush so it looks like nothing was ever there. than where the flapper is he put a pipe plug in there. it sits flush so i dont think itll affect flow at all nd i doubt itll back out. im only gonna run 7psi and maybe 12psi max. depending on if my tuner goes for a safe tune or a all out. i said all out, but he doesnt want anything coming back on him. which i understand...

[timg]

It should be 1 bar. If you put in a different MAP sensor, expect weird behavior from the PCM. You can change most of the settings for it, but GM NA OS's seem to freak out when they see boost.

Tim

[beastberetta]

so a 1 bar would be ok for lets say 14 psi max? maybe if that. most likely 12lbs max but i might want to put it on 14lbs one day. i think 1 bar is 14.7 lbs right? is 14.0 lbs pushing it?

[timg]

1 bar means it won't see anything above atmospheric pressure. For 14.7 psi, that would be a 2 bar sensor. Anything over 1 bar is likely to cause computer tuning issues with OBD2.

Tim