Steedspeed made sure the twinscroll paths are divided all the way to the WG valve on their twinscroll manifold. I have never read anywhere that twinscrolls don’t actually have to be divided along the entire path through the manifold and turbine. I think you lose some of the benefit when you combine the pulses for 2-3 inches of that path in an undivided wastegate pipe stubbed off the twinscroll turbine housing. I think you telling people it does not matter isn’t really a good idea.
For the record, I'll be using an open, non-divided housing with the 8374. Would love to go twin scroll but it adds quite a bit of cost, extra custom fabrication, and moreover, the wg flange welded to the turbine housing is shown to fit within the Z3 chassis per my friend's set up.
I do not have enough knowledge or experience to give an opinion on housing-mounted wg flanges, twin-scroll or otherwise. It's common enough that I'm not too worried about trying this route. But I will try and keep the flange as short as possible as I imagine the larger the wg flange in this scenario, the longer it would take to re-spool as the area of the pipe would have to normalize exhaust manifold pressure. Like hypothetically, if the wg flange was 10 feet long, that total area would become part of the total manifold area and would thus take longer to pressurize. But with only a 6" - 8" run to the wg, I think it will be negligible.
Whoa an argument I am not involved in.
How do I enter?
~Ken~ '99 M coupe THE "original" TT Stage 3 - HTA3586R; 701 whp 672 wtq @ 26.5 psi ; NeverSell - CoupeCartel
Repeat what your friend has done exactly, but with the s52 intake manifold . I’m currently running a Trm kit with a spa 6000 turbo it makes 420whp at 8 psi(schrick cams 93 octane).
With the z3m space is an issue, and with the spa manifold boost control usually isn’t an issue.
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“If liberty means anything at all, it means the right to tell people what they do not want to hear.”
― George Orwell
Too late!
turboandstuff.jpg
efr 8374 ready to go. Next step is to start tearing down s52. I'll have machine shop freshen up the head and deck block if needed. Otherwise I'm doing as much work myself as possible, but have a question about cylinder/piston diameter:
I assume I will need to have machine shop measure cylinder diameters before I order pistons? s52 only has 85k miles - my assumption is I want to stick with the stock 86.5mm diameter if possible for thicker walls. What is the best approach here?
I'd personally get the machine shop to check and measure the bores before you order pistons. Never know, you could have some issues in the bores and need to oversize them a little.
It is always best to order pistons after you (or a machine shop or your engine builder) takes bore measurements following disassembly. In addition, stock cylinder bore on an S52 is 86.4mm (not 86.5mm like you stated in your prior post). Typically a machine shop will just hone the cylinder if it's in otherwise serviceable condition, producing an 86.5mm bore. This is what was performed on my built S52, which has JE pistons & Eagle rods.
I disagree a bit - an S52 is a tough choice because of the bore size, but I would never just hone an inline 6 because of the possible run out from the front to back being a long block. If I am building a stock commuter engine, sure. But a high power turbo or supercharger setup that is going to be leaned on I am going to want a torque plate and bore so I'd just order 87mm pistons and have the block fit to the pistons. I buy 85mm pistons for M50/M52, also. It's easier and way way way more appropriate for the build. If you're having a machine shop hone a high mileage block to put a turbo engine together then just bottle hone it yourself and see how it goes - just my opinion, not an engine builder, just an engine user. I would not try to stay stock bore size w/ a hone unless the engine had already been re manufactured that way and you had a part failure that did not compromise the bore.
Update
Engine is torn down and ready to send block and head to machine shop. Efr 8374 with SPA and AGP T4 housing fits (s52) but is close. Reminder that I will be welding the wastegate plumbing directly off the turbine housing. Looking at the picture I will have a bit of an angle but should not be too bad.
I'm grateful if anyone has recommendations for the below:
Good Seattle-area tuner?
Good Seattle-area machine shop? (C&D Performance has been recommended)
Good Seattle-area fabricator to weld WG port to housing, and eventually fab remaining downpipe plumbing?
Thanks all!IMG_1258.jpg
Last edited by Z3eattle; 01-06-2023 at 03:57 PM.
CES got about 700 rwhp out of the EFR 8374 years ago, with great response. I think the details were posted here.
Progress...
Head and block back from machine shop; upgraded Supertech inconel exh valves, mild port around valve seat area, torque plate bored to 86.5 and main/rods align honed. Engine assembly started.
Question - would a 44/45mm WG be a good choice here in terms of mitigating boost creep?
Reminder that specs are: efr 8374, no IWG, T4 single scroll w/WG flange welded to exh housing, SPA mani w/WG port welded shut.
15psi on 92 pump gas target.
head.jpgblock.jpg
My goal is linear throttle/power delivery vs total hp figures. With my built engine and turbo size, I'm sure 700+ numbers could be possible with e85. But I'm going for a sort of under-tuned/over-built approach to have a more reliable street-driven track car that will last 'longer'. Want to stick with 92 octane pump gas (Washington state highest available) for the street but will use higher octane for track days for safety margin. Also sticking with s52 manifold vs the more popular m50 obd1 mani with the emphasis on more lower end torque vs total power potential.
So given this philosophy/approach... I'm hoping that the 45mm WG size will help mitigate boost creep but still work with the above goal @ what I think will be around 15psi on 92 octane?
This is my first turbo build so open to all ideas and feedback. You all rock for helping me out with this!
- - - Updated - - -
C&D Performance
https://youtu.be/FsqZiWxLI8M
Just posted this in another thread, but it seems to fit here. Most people find the m52/s52 small runners to choke similar to a restrictor plate shooting for more than 400hp. going out on a limb, seems like the m50 manifold feeds the runners right behind the t.b. more air under boost. The thinner plenum on a m52 manifold would add to this issue imo.
Ive looked for higher than 400 hp builds on the m52 manifold and havent found one. Could you cram more boost to make the power? Probably. . Its not going to help efficency.
Last edited by Sio2crew; 04-15-2023 at 11:03 PM.
That's a good point - is the 52 manifold simply too small for turbo applications in general for a 3.2L block, s52 head and cams? If the overall power loss is really that great I'd certainly go the route of larger intake/plenum flow.
In the video you posted, the 90 degree pvc home depot fitting that was never designed to seal on the embossed outer-diameter?? Perhaps other things were also rectified before the +130hp gain was obtained? I'm not trying to sound controversial, just looking at things objectively. Def worrisome about no 400+ hp figures on s52 mani. Thanks! I will def need to research this
I agree 100% they made other changes than just the m52 intake.
I almost think it was a different video that he talked about the m50 only change... just cant recall having seen that video a long time ago.
I do know alpina used the bigger 540 throtel body on their 3.2. Ive read that the alpina intake was a comprimise between the m50 and m52. Similar to the schrick intake. (Bolth are rare as hens teeth)
Ive also read that the change to the m52 intake had more to do with the u.s. emissions standards than increased mid t.q. ( internet lore of course)
Last edited by Sio2crew; 04-23-2023 at 04:56 PM.
1989 535i - sold
1999 M3 Tiag/Dove - sold
1998 M3 Turbo Arctic/black - current
2004 Built motor TiAg/Black - Sold
2008 E61 19T Turbo-Wagon - current
2011 E82 135i - S85 Swap - current
1998 M3 Cosmos S54 swapped Sedan - current
1998 Turbo: PTE6870 | 1.15 ar | Hp Cover, Custom Divided T4 bottom-mount, 3.5" SS exhaust, Dual Turbosmart Compgates, Turbosmart Raceport BOV, 3.5" Treadstone Intercooler, 3.5" Vibrant resonator and muffler, Arp 2k Headstuds | Arp 2k Main studs | 87mm Je pistons | Eagle rods | 9.2:1 static compression, Ces 87mm cutring, Custom solid rear subframe bushings, Akg 85d diff bushings, 4 clutch 3.15 diff, , Poly engine mounts, UUC trans mounts W/ enforcers, 22RPD OBD2 Stock ECU id1700 E85 tune, 22RPD Big power Transmission swap w/ GS6-53
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