Coinshark

Hello all, I'm currently in process of building. S5 NA rotors in S5 T2 housings and irons. I am installing a mega squirt for ecu and will be making a custom manifold and exhaust most likely with a v-mount set up. Anyways, I primarily use it for autocross so throttle response is most important. I'm looking for somewhere in the neighborhood of 350hp. Here's my concern, I have a source for a very very cheap BW S366 with div .91 ex. From everything I've been reading it doesn't sound like a good option for the range I'm looking for. What sizes would you recommend. No to EFR prices though. I'm not poor but, I'm not rich either.

Holding breath for responses and other questions you have.

Shainiac

iTrader: (7)

Borg S257 SX-E would be a good fit for under $1000. Its basically the EFR 7670 without the TiAl turbine wheel and double ball bearings. Problem is, after you spend money on a quality welded twin scroll manifold, dual wastegates, and a blow off valve, you're not too far off from an EFR with the cast Turblown manifold. Plus, the EFR will have more re-sale value if you look to upgrade down the road.

Coinshark

Well, the good news is that I already have a Tial BPV I will be using, fabbing my own twin scroll manifold.The person that has the s366 also has a s300sxe 8376 for a steal of a price as well. It's on the lower end of the map with plenty of room for future increases I believe. I'm hoping to find a good set of S5/S6 turbo rotors but, for now I will plan on reusing the NA rotors.

BLUE TII

iTrader: (9)

I would use a ~$750 or so used IRL EFR 7163 with a real HKS or Greddy wastegate (used?) for boost control to get max bang for buck for your application.

Go ahead and remove and weld the SS turbo exhaust housing to the collector to save money, time, complexity and weight (you can get another all day for peanuts).

Basically an improved Apexi RX-6 turbo kit for pocket change and easy to fab the 2-1 round collector with single wastegate (look at 3rd version of the FD HKS T04Z manifold for inspiration or get one used).

Kinda like this but no flange for turbo (weld exh. housing on) and probably a cheaper bolt on wastegate/flange.

Coinshark

Noted on the turbo. I'm not scared about the fabbing for the manifold. I work in a machine shop

BLUE TII

iTrader: (9)

When I say easy to fab the 2-1 round collector with wastegate take off, I mean it is much easier to end up with a great high flowing high velocity merge than with the traditional divided T4 flange and wastegate entry which actually takes a lot of time/work to get it nice with a good transition and WG take off and is still a point of failure in use (flange warp and gasket).

Wasn't implying you suck at fabrication.

Coinshark

Lol, didn't take it that way. Main reason I want to make my own is to properly plumb the wastegate. Most manifolds, from what I've seen, have the gate really far away are just asking for boost creep and slow response from the gate. I only say this because of the experience my boss has with his 2,000 hp LS build. . He's the one giving me the killer prices on a used/rebuilt S300sxe. He keeps joking with me about putting a 106mm that he has on my engine.

My goal is to have the wastegate(s) be plumbed straight out of the ports so that they are the first path for the exhaust gases. That way the gate will vent quickly and accurately.

BLUE TII

iTrader: (9)

Well, on the wastegate it really is a balance on priority and placement.

I had a past with boost creep so when I converted my manifold I went "all out" on the wastegates with two high priority 44mm wastegates.

Great, but then I had the opposite problem of boost creep. Exhaust flow and pressure at high rpm would push against the bottom of the WGs' poppet valves and keep them open further than the actuator on top was driving them to and boost would drop.

Fine by me as that just lets the engine breath and I still was pretty much able to max the turbo compressor. I could have fixed it by plumbing the WGs as dual port with boost on top of the actuator.

Anyways- found some pics.
This is all the FD RX-7 HKS T04Z turbo kit manifold (fits FC depending on turbo though WG flange hits subframe a bit).

Version 1

Version 2

Version 3

My dual WG conversion

A look at dat merge

Coinshark

Thanks for the reference pics!!! When you had boost creep were the gates only using the spring or was there pressure being applied to the top of the dome as well? That's what I'm hoping to do with EBC. I will have to model up the manifold and show you what I'm proposing I think. If I did one gate I think I would get one that is divided at the flange still so that nothing can cross over flow wise.

BLUE TII

iTrader: (9)

A side view of my manifold.
Because of the proximity to the engine port of the original manifold's WG entry and the high priority merge angle I put the WG at exhaust flow/pressure against the WG poppet valve affects boost control.

Coinshark

I like it

BLUE TII

iTrader: (9)

No, the boost creep was on my old "stock" hybrid turbo.
I put a 60mm external vented WG on it, but it still had boost creep.
I had to max port the stock exh. manifold and turbo inlet up to the WG inlet as well as widening the turbo scroll slot entry into the exhaust wheel to stop the boost creep. Which slowed response (how fast boost came up), but did not affect spool (peak boost per rpm the turbo made).

BLUE TII

iTrader: (9)

Thanks, but do as I say not as I do LOL.

That is $900 in wastegates and if you use cheaper ones they will fail.

The HKS T04Z manifold V3 evolution is a thing of beauty with simplicity, strength/reliability, flow and boost control- while being easy to replicate on a budget.

Coinshark

Haha yeah. I will keep it fully divided and make or get a wastegate adapter that is divided until the poppet to keep it divided without crossover. Most likely use a Tial gate or turbosmart 44 or larger. I will put pressure on the dome to help keep it closed using a ebc solenoid.

Hopefully the S300sxe 8376 will be a decent size for what I want to do.

Thanks Blue!

BLUE TII

iTrader: (9)

I tried the divider up to the WG poppet flange twice (version 2 shown in that pic of stock hybrid). It only welded itself to the poppet valve once and cause overboost LOL.

It also had a couple failures. First time the stainless plate broke the welds and then folded up like paper.
2nd time I used thick 3/16" stainless and made it so it could expand so as not to put stress on the welds (welded divider to a ring that was free in the pipe on the WG end). It lasted longer, but it ended up tearing the stainless divider right where it met the tube in half.

So, I left the divider out and it barely made any diffrenence- just a bit less spool off idle to 2,000rpm.

Just a word of warning on how veracious the rotary exhaust is.

It actually also bent in the cast iron walls between runners on the exhaust housing and turbo manifold a bit- pushing it toward the rear straight runner as the snakey front runner had more exhaust manifold pressure. But that was after 7 seasons of racing.

Coinshark

Well, as it turns out I'm getting the turbo for free which means it's the right turbo for the job. Winning!