4 bolt to 5 bolt turbo hotside difference's?
 

well whats the difference?? dose one make more power then the other?? really whats the difference in all aspects. i here about them but dont see much info on them. im looking into 50trim sized turbo's and this has come up in my research. so can you guys help me out. thanks all

anyone??

I asked the same question many times and no one could tell me if one was better than the other, I think it just makes it easier to attach the 02 housing on the 4-bolt version (on some applications)

I emailed Joe @ Precision turbo this same question a few mths back and this was his reply to me "I have seen both applications used on EVO's, so I really think it comes down to whos kit you plan on using. Some kits use our five bolt housing, whereas others are designed to use the Garrett four bolt housing. I would highly suggest you contact AMS as they are one of the leaders in the EVO market."

FYI - AMS uses Precision turbo's which are 5-bolt exhaust housing on their kits.

4 bolt is better.

There was a shop from this forum that did a test switching nothing but the hotside. This was on a 400whp car.

400whp on 5 bolt

420whp on 4 bolt

5% increase with nothing changed but the hotside.

The reason the 5 bolt's are popular is because the A/C can get in the way of the downpipe on the 4 bolt's.

There are kits that avoid this, but you'll have to do some research on which ones.

So why does one perform better then the other??

And your saying that the 4 bolt's are better??

the theory is that the old ford 5-bolt discharge design is more of an on-center turbine housing and is supposed to be not as efficent as the newer 4 bolt design.

I have the 5 bolt housing on my gt35r and it spools uber quick! I have yet to see another 4 or 5 bolt 35r spool up like mine does on a 2.0l EVO stock engine. I'm not talking about watching the boost gauge as I get into boost. I'm talking about using a map sensor to log pressure and comparing that to RPM to get real data. ALOT of people say 'ohh man my 35r is fully spooled by X RPM' but unless you are logging boost and looking at HARD data you're just guessing.

There is a pretty large 'GT35r Spoolup' thread on here with comparisons on different peoples setups, might be worth it to check out.

Now, having said that I think there are other, more important factors, that come into play when you're talking about spool up. But I wouldn't lose any sleep over having either hotside on my 35r.

I think the 1st post said he was looking for 50trim sized turbo's. A 35r is much bigger. Do u think your reseach would differ from what a 50trim sized turbo might see????

So maby the 4 too 5 bolt hotsides for the 50t is what makes or brakes the 500hp mark. Just a thought but anyone care to give info on that???

First of all the 5 Bolt housings that AMS and MANY others use is usually reserved for an INTERNALY gated turbo. This allows them to run the external wastegate on the downpipe flange. It is a good way to save space

As far as the AC is concerned, that is complete bs. You can incorporate both housings and fitment with the AC is spot on. NO difference

Also, In some cases boost creep is a concern on a 5 bolt housing using the internal gate hole as an evacuation point for wasted gas

Ok well what I'm looking for is a 50t. I want 500 or as close to it as posible hp. What hotside should I do?? 4 bolt or 5??

Here is my take on this. We use PTE's 5 bolt housing in our kits as I feel they make better overall power than an equivalent 4 bolt housing. Spool up and midrange power is better, however the top end may suffer a bit. I'd rather give up 5% of peak power to have something that spools faster and has more midrange power. On the street that difference makes a car much more fun to drive.

Shearer

What is the difference u think?? Noticable to the average street\drag. I'm looking for bad ass street power but want as close to 500hp as posible. Do u think one would be dissapointed in eather hotside?? What's the spool up difference?? We talking 100 200rpm or 600 800 rpm difference??

Anyone able to reply to my last post?? What are other's info as well. Thanks guys for all the clean good info so far.

Are we talking standard 4 bolt (t31 I think it's called) or gt 4 bolt? I guess since were talking 50 trim it's a t31 4 bolt, I don't see how a hole punched in the side of the housing disturbing flow increases spool.

Have you done any back to back testing?

This is the first time I've heard anyone say the 5 bolt's spool faster and make more midrange than the 4 bolts.