GST HX35 or HX40?

[Boosted98RS]

Well I'm in debate right now. I'm about to pull the motor and get it rebuilt and make sure everything is in perfect condition. Here will be my motor specs

6 Bolt block
Eagle Rods
Weisco Pistons
ACL Main Bearings
ACL Rod Bearings
Cometic Headgasket
Debating on cams either staying stock or going with Brian Crower 272/272

I will probably be keeping a running just a ported 2g stock manifold and was debating on an HX35 or an HX40? Which one would work better on a GST? I mean I will be keeping stock intake manifold and using the ported 2g manifold. Will cams still be beneficial? If I go with the HX40 most likely I will be using nitrous to spool it up probably a 50-75 shot or so. Also debating on E85 or not... The closest station is about 30 miles away but this won't be my DD so it's not a big deal. But trying to outweigh the pros/cons of this. I will need to buy injectors anyway so that's no big deal? My goals on the car are around 450-500 HP. Any suggestions are appreciated!

 

[1gDSM4g63]

A HX-35 is pretty capable of your goals and I suggest you do cams too.

 

[constant_proj21]

Hx40 on e85 will make 450-500hp on a gst, pretty easily with supporting mods (this all depends on the dyno you will be on though). Could prob get away with using an hx35, but will be pushing the turbo a little harder. Highly suggest, a set of hks 272's, they will definatley be benificial.

And if you haven't already, read up as much as you can about the different holsets. There's a couple very good threads, that will give ya the info you need, to choose your turbo.

 

[Boosted98RS]

Hx40 on e85 will make 450-500hp on a gst, pretty easily with supporting mods (this all depends on the dyno you will be on though). Could prob get away with using an hx35, but will be pushing the turbo a little harder. Highly suggest, a set of hks 272's, they will definatley be benificial.

And if you haven't already, read up as much as you can about the different holsets. There's a couple very good threads, that will give ya the info you need, to choose your turbo.

Yah I have read into teh holset turbo's quite a bit but just can't decide right now. It seems like everyone who has an opinion on them is always AWD and no FWD guys so I'm tryin to get the FWD guys to chime in, .

 

[constant_proj21]

Well you will see a bit higher numbers, being your car is FWD. A friend of mine made 446hp (dyno dynamics), with an hx40, 272's, on e85. But without all the drivetrain loss created by awd, wouldve prob been a 500hp car. That's why you could get away with a hx35. Then all you have to worry about is traction, haha, won't be an easy task.

 

[Boosted98RS]

Well you will see a bit higher numbers, being your car is FWD. A friend of mine made 446hp (dyno dynamics), with an hx40, 272's, on e85. But without all the drivetrain loss created by awd, wouldve prob been a 500hp car. That's why you could get away with a hx35. Then all you have to worry about is traction, haha, won't be an easy task.

I am def. worried about the traction issue... I just got this GST for real cheap with quite a few mods and figured I would mess with it. I figured a set of M&H on the front on some drag wheels and I might be able to hook by 75-80 MPH, ha. That's why I was thinking about getting the HX40 so it would give me a little more time to get traction but with nitrous it probably won't help anyway. I just want to get the most out of the built motor but yet keep everything safe.

 

[1gDSM4g63]

Uhhh... I think going the a HX40 with a shot of nitrous oxide will be even more of a traction issue than if you were to go with a HX35 without nitrous oxide. You do know that the spool difference between the HX35 and the HX40 roughly like 500 rpm right? But an HX35 will easily make your goal range and if e85 station is an issue you might as well get methanol and stay on pump.

 

[abaum565]

Hx35 with e85 and at a boost level worth while for the turbo gets me absolutely no traction! It hits fairly hard and doesn't stop until you let off. i don't have an lsd, and its frustrating.

a hx40 may come on a little later to help with traction, but I can't speak for that yet.

 

[Dewayne Waldron]

Get the hx40, replace your control arm bushings and motor mount inserts if they havn't been already. Get a good set of struts and definately get some better meat for the front. I would also recomend upgraded cams like the Kelford 264/272 combo. No Spray.

 

[FLASH1970]

I'd say go with the HX-40 for helping a little with traction. Also, if you plan to go 450-500hp, the 6 bolt rods should be fine. Just get some ARP hardware for them.

 

[dsm-onster]

If he wants the turbo more laggy, he can just roll into the throttle slower . . .

The hx35 can definately meet your goal with e85. You'll need 1250s or more an twin 255 walbros or larger single for the 500whp area though. . . to be safe.

If you get arp rod bolts you need to line hone the big end as their different clamping force may distort. The arp rod bolts are definately not neccesary for your goal. The pure stock 6bolt block has done 600whp on more than several occasions. Rod bolt upgrades are more for high revving, as it keeps the rod on the crank during the transition from "up-stroke" to "down-stroke". Pressure on the piston that translates to torque puts very little stress relatively on the rod bolts.

 

[Boosted98RS]

I think I'll probably just go with the HX40 from what you all are saying. Maybe it will spool a little slower and help out with the traction issue I'm sure I'm going to have. I'll put some nice drag radials in the front and I already have motor mounts. The car has ARP studs already in it with built motor with Weisco Pistons and Eagle Rods I am just going to get them looked at to make sure everything looks good. As far as springs should I leave these stock? Should I get aftermarket valves for the car?

 

[abaum565]

the hx40 is no snail by any means, it's still going to be a violent turbo that will break your tires loose, radials or not!

 

[dsm-onster]

Yep, 20psi by 4K with that highflowing hotside means worthless 1st and 2nd.

Point is that you'll going to eventually just learn how to roll into it right for your setup. And spend some money on traction, if you get tired enough of it.

 

[rampridersrider]

HX35 with the 12cm housing will spool about the same as an HX40 with a bolt on housing. Personally, if it were my car, I would do the HX35 with the 12cm housing, then buy an LSD and an electronic boost controller. The boost controller can control gain and how hard the turbo comes on by slowing opening the wastegate. The LSD is a ####ing must, don't cheap out on that. Thats going to be one of those things that completely changes your car. And your car with some good drag radials up front, an LSD, and a properly working EBC will dead hook from a 20 roll.