free vs. practical (turbo content)

so long story short I have a HE500 holset turbo that i got for free, there isnt much info i have found about the he500 becides thats its somewhere around a hx52 - hx55, i havent messed with it much but i do know it has a 16 cm^2 exhaust housing. once i get the 302 running in the race truck (see build thread 5.y0ta) then i will start piecing together a turbo kit. the 302 is from an 85 mustang, nothing done to it becides an edelbrock intake.

holset dosent like to give out alot of compressor maps or a/r info for there turbos and ive read alot of mixed things about how big/small these turbos actually are, from what ive read on mustang forums is that a hx40 is more suited for a stock 302, but its hard to beat a free turbo.

so with a pretty much stock 302 that wont ever see over 5700~ rpm would this turbo be to big and laggy? i am only wanting to push 7~ psi on the 302 or atleast enough to break 300 rwhp. i would really like to keep it since it was free and since i will be building a 351 in the furure and i think it would be a much better fit on that, and i dont plan on doing anything to the 302, just leave it stock and have some fun with it.

I have nothing to add, except that 300 bhp shouldn't be hard, NA 5.0s can do that.

when it's free i wouldn't worry about lag, esp. if you're not dropping the motor's compression to accomodate the turbo, all the power it makes N/A is the amount of that you'll have before it spools. With that being said i wouldn't go crazy with the boost without building the motor, the turbo will handle a lot more then motor will and even with the turbo being free expect to easily spend 2-3k on supports mods (XCAL 3 and tune, fuel pump and injectors, manifold, wastegate).

yea good points, once i hit 300 at the wheels ill lock the boost in there and call it good until i get a motor built, i would like it to not blow up before then

and i should have mentioned it is carbed. im trying to keep it as cheap as possible but still not cut corners. the plan is to use a carb enclosure so i can use the carb i have now (will just need nitorphryl (sp?) floats), also for manifolds i will use a flipped block hugger header on the passenger side with the turbo on top of it and have the driver side header go down around the back of the engine and Y up into the turbo. for fuel i just need a good inline pump that can do atleast 15 psi and use a boost referenced fuel pressure regulator. then there is BOV, wastegate, intercooler and piping, i would like to keep the budget for boost around 1k but like most budgets itll probably go over some haha

Rule 1 of turbo setups, never build a setup around a turbo. Rule 2 of turbo setups, rule 1 can be ignored if the turbo is a BorgWarner EFR.

I'd never ever ever use that turbo to make 300whp on a V8. It'll be the worst 300whp you'll ever feel. Ridiculously lazy.

Sell it and get one that's sized properly.

People are generally happy to trade something for something bigger . Especially in the land of turbos. Perhaps trade to the right size?

I know it's not proper, but what about applying that turbo to a completely stock 302 and then having the wastegate set to bleed pressure off pretty low. Basically a light-pressure turbo setup. Lag shouldn't be much of an issue because it's only adding boost pressure to an already torquey engine, right?

That said, if you want 300hp out of a 302, and the engine is in good condition, a set of headers an some higher ratio roller rockers with the cam out of a Mustang GT should get you there once properly tuned. I don't see a reason to turbo a 302 unless the power goals are north of 400 and you don't want to deal with overly high compression & a lumpy cam.

That's something he'd have to do either way. I doubt the wastegate is anywhere near 7psi on this thing. So that'd be custom work.

Then because it's a monster turbo not made for gas engines, it's going to need to be around say.... 30psi before it's even efficient. Driving huge turbos outside of their efficiency range isn't nearly as fun as it sounds. Lower boost levels = more lag = less fun.

the 300 hp goal more or less just to get the turbo set up together before building a motor that can handle more, i plan to get the truck together in steps so i can still have some fun with it in between rather then just have the truck down for an extended period to get everything done at once. should go as something like this:

-get truck running/driving -enjoy truck while piecing together turbo stuff -boost stock 302 -build another engine while enjoying boosted truck -put in build engine and apply turbo stuff

but you guys are probably right about finding a better fit turbo, i can always trade back up when the time comes

anyone got a hx40 they dont need?

Yeah, makes sense I guess, I haven't spent tons of time staring at boost maps and put the real study time required to read the whole situation better.

And, honestly, 300hp on a 302 is easier than falling down. If I keep my Mustang I'll be shooting for that sort of power level anyway (but, honestly, I'm starting to think I'd be smart to sell it).

Holsets love/need lots of boost (ie more than 7psi). You're not gonna be happy with the set up. If your goal is 300hp and low boost probably just go with a turbo from a 2.3

I dont think any holset besides an HX55 running ALLOFIT is going to be happy mated to a 302. An HX40 is closer to your goals power wise but I think you'll be putting it in a crappy part of the compressor map.

yea the internal wastegate was never going to be in the equation other then the fact that is was going to be locked closed haha

Leafy wrote: I dont think any holset besides an HX55 running ALLOFIT is going to be happy mated to a 302. An HX40 is closer to your goals power wise but I think you'll be putting it in a crappy part of the compressor map.

I think the answer is twin HX35s.

Swank Force One wrote:

Leafy wrote: I dont think any holset besides an HX55 running ALLOFIT is going to be happy mated to a 302. An HX40 is closer to your goals power wise but I think you'll be putting it in a crappy part of the compressor map.

I think the answer is twin HX35s.

after doing some more research it seems like the hx40 has been done with a lot of sucsess according to mustang forums, probably the route ill end up taking.

and ive already had to talk myself out of doing twin hx35 a few times haha a pair mounted on some flipped block huggers would be awesome but in the long run its more cost and more to fail but im not against maybe being talked back into the idea haha

Looks like you need about 4 psi to produce 300 horsepower without intercooling using an HX40. Probably similar with the turbo you are looking at, slightly less given that you have a relatively small exhaust housing on it (HX40 sized I believe).

This is an HX40 map (taken from http://www.squirrelpf.com/turbocalc/)

Basically since you are running without an intercooler, to get to 300 horsepower the 4 psi the turbocharger is giving the engine is offset by the much higher intake temperatures...you can get the same 300 horsepower with no turbocharger, and no time spent trying to fab an impossible 4psi wastegate and all the associated plumbing.

i do intend to use an intercooler, i dont think i would ever boost anything without one

i should also clarify that my minimum goal is 300, i should have said more around 300-350 hp is what im shooting for since that seems to be what ive seen other stock 302's make with around 6-7 psi

i plan to do more boost on a build motor down the road so 300 hp isnt the end goal, that is just for this stock 302, so all the piping for hot/cold sides will stay with the truck

I realize I may have muddied my first response with too much detail. To answer your question: yes it will be too big and laggy. J