What do we think on this front. Would a 20B spool 2x GT4092's as well as a GT4202R? Not interested in the cool factor so much with the twin 40's but I have been offered a pair.

 

Personally, the single turbo setup is a lot simpler as the 20B spools both of those quite nicely from what I hear. I don't have either turbo so I can't say honestly

 

I'm not worried about how complicated it is that's the joys of being a fabricater. It's more weather it's a good set up on an extended street port. Can always go semi pp?

 

I don't see any advantages to using 2 parallel turbo's on a 3 rotor. Just get a GT(X)4202R with a Tial 1.15 housing and call it a day.

thewird

 

I agree

 

It's not is there an advantage as such but beyond weight is there a disadvantage? As I have two 40s and the 42

 

disadvantage is having an additional point of failure for the twins setup..

 

Fitting one turbo with a 20b is a challenge already, good luck fitting 2. Why do you want to add more heat to the engine bay? They're probably gonna spool slow too.

thewird

 

Getting a single 42 in on a 20B isn't and issue at all. Yeah the heat thing may be something to think about in more depth but with decent ceramic coatings and turbine housing blankets its manageable.

Spooling I can't see there being a massive issue. They are both on .95 housings being fed by a large ported pulsing 20B... Ultimately without knowing if anyone has done it, no ones knows...... interesting to get people veiws

 

There are plenty of reason to use a single.
No good reasons to use twins.

NTM, pretty sure those two gt40's are a lot more turbo than 1 gt42, just from the looks.

 

Yes indeed alot more turbo.

What's your reasons for single over twin.

 

twins for cool factor

 

Your twins are gonna lag like a **** which for a 20b is stupid. A/R has nothing to do with the flow (in this case).

You obviously want to do it so just do it and stop trying to find reasons that its a good idea cause there are none.

thewird

 

Was waiting for someone to say that. The point of these fourms is to share discuss and explore ideas, options and exploring ways to tune these mental motors. If I simply wanted to it regardless of the pros and cons the I clearly would have as I have the means and the parts to do so. So I'd ask what's your reason for the 40s being 'laggy like a ****'. Is that based on any form of testing or experience with 40s or a well calculated opinion.


One of the guys on the UK forum is aware of someone running a huge peripheral ported motor with twin charge coolers etc on twin 40s. Trying to get more info

 

It's an educated guess. Its almost double the turbo you have to spin... The GT4202R will kick on hard around 4,000 RPM plus or minus whatever for setup efficiencies. Your twins will probably spool 5k or greater.

thewird

 

The gt40 is still a rather large turbo. Thewird is correct on his assumption of lag. Your still splitting the exhaust energy between the two. Half the energy will take longer to spool. Hell each turbo is gonna get less energy even when compaired to a regular 2 rotor. IMHO this would be a drag only setup.

Edit: Going non sequential on the fd twin turbo setup is the same laggy principle.

 

I'd also say it's tricky enough to have a good spooling "Divided" manifold/turbo(s) with an extra rotor thrown in the mix, let alone another turbo.

 

one big ball bearing