What HX35 housing will make more HP, 16 or 21?

[bgilbert]

Let's say you want to make the biggest HP number you can with a Piers (hybrid) HX35 and a set of custom EDM's. What housing would make the most HP, the 16cm or the 21cm?

Reason I ask is I always hear about how the bigger housings on twin setups will make more HP etc.

The plan is to install my Scheid EDM's in my auto 91.5. It currently has a Piers 35 and 16cm housing. I figure I might shell out the $75 to Dunbar to dyno at IRP or Bowling Green, just for play. I don't think I'll have an upgraded 4" variety turbo by then so I'd like to get a decent number with the 35.

I got a feeling the 21 will make more ..?

[Greenleaf]

Bill,


Did you somehow get ahold of my three ring binder?



-S

[JLeonard]

Bill I think you are right.
You will be up there in rpm when you max out so you want the air and less restriction at that point. And on a dyno lag is not an issue.

Jay

[Cschafer]

It should breath better so I guess it should make a little more top end in therory but at the rpms your gonna run does the engine move enough air to make an 18cm housing restrictive? If you can't even overrun an 18 then I guess a 21 wouldn't do any good but I don't know how to do the math for that if there even is such a calculation. However due to the extreme overfueling your gonna be giving that little turbo you might want the 21 to have a chance in not blowing it Sounds fun, do you know any trans shops to fix that when you burn it up?

[Greenleaf]

I ask that you guys stop this pronto. I have folks sending me the 21 housings for free. Your going to tip the boat and they will become the hottest thing since the two piece swim suit.



Stop it I tell yah

[wannadiesel]

How much boost are you seeing with the 16, Bill?

[Cschafer]

How many 21's can you possibly need Scott? Or are you stock piling them to sell when Bill makes them valuable?

[bgilbert]

You guys are not right . That would be something if I stumbled onto something.

How much boost are you seeing with the 16, Bill?

With POD's I've seen as high as 40psi. But then turned the pump down to where I see around 33-34psi. If the 1psi = 10hp rule is right, which I know it's not for the most part when dealing with non-stock engines, these Scheid EDM's would be +100hp over POD's. With my 89 and how it's set up, I gained 10psi of boost over the POD's, with no changes other than injectors.

I've always agreed with GL about the use of the 21 housing. It's great for some applications. I suppose my goal for this idea would be to be the first to break 400rwhp with a hx35 . I know the auto will hurt me big time though. Or is it, I will hurt the auto big time ?

Off subject, I did stumble onto something else with this $1200 truck, an almost leak free intercooler (big thumbs up!). I pressure checked the system and it held air and I never seen any bubbles from the IC. The IC on my 89, it's a leaker. Some of the TDR guys nicknamed it my 'wastegated' IC. With the same setup (injection pump, turbo, housing)in my 89, I never seen 40psi of boost, most was around 35-37psi. I think in time, this IC might make it's way onto my 89.

[Greenleaf]

I have serious doubts you will harm the transmission. Ask me how I know.

[Begle1]

That much fuel with a 21 would have a rather extended spool up time, wouldn't it?

[Greenleaf]

Yes. It's simply awful. You woudn't want one, nor would anyone else.














did that sound sincere enough.............i hope they bought it.

[PToombs]

I bought it!

[jer1]

O.K. GL, give it up, at what rpm does she start to spool, and when is max boost achieved? I know it's top secret and all, but I won't tell anyone!

[wannadiesel]

With that little boost I don't think you're going to see much difference in HP. Maybe 10 HP. It's not like you are seriously overdriving it with the 16 cm. It certainly will drive better with the 16 cm.

[Greenleaf]

It certainly will drive better with the 16 cm.

The manual trucks will drive better. I don't spend much time in any, but have driven them time to time.

Acceleration? In either truck it can be an issue. However, if your driving like you should and not attempting to race a honda from the stop light, it's not an issue, especially for the auto. I have driven a manual with the 14 and it felt like I was pulling 10,000 lbs for the first 75 feet after each shift.

Remenber; daily driving characteristics and making HP are two different aspects. Unless your building a 1/4 mile truck, then you have other issues at hand.

It would all depend upon your goal.