Log or ramhorn manifold for EFR6258
 

I'm in the process of fitting a BW EFR6258 to my 1.8 built 1999 Miata. The plan is to reach 320 whp maybe more.

Now I can either go log, short tubular with collector or full ramhorn style manifold.

What's the concensus on which is the best compromise for spool and top end?

Anyone tried both log and ramhorn on the EFR6258 have some comments?

I chose to go ramhorn with the shortest runners I could do while still having a good collector and equalish length. Having a good collector is the whole trick with exhaust manifolds. I also chose to go with 1.25" sch40 rather than the normal 1.5" because IMO 1.25" is fine for the amount of power the 6758 or 6258 can put out, it might slightly choke the 6758 running ALLOFIT but thats like the difference between making 430hp on e85 rather than 450hp. Packaging the EFR on a true log could also be difficult since the compressor cover is closer to the manifold than the turbine flange by like half an inch.

Mine sticks the turbo as low as it can reasonably go. If I was going to make it again, I'd move the turbo just a smidge higher in the engine bay. Then I'd be confident that it would fit on every miata, right now its super close to everything.
https://www.miataturbo.net/attachmen...ine=1403181212

Ok nice setup

Have you got any spool data available?

Lloyd

No, havent gotten around to it. But it will make 2 psi at 2200rpm in 5th. :rofl:

I cannot answer your question directly but this may give you a data point.
I made a top mount tubular with 1.5" runners to be able to keep AC PS and it is making 314hp at 21PSI.
I would go with 1.25 runners if I was doing it again.
Good luck with your project.
https://www.miataturbo.net/attachmen...ine=1403192995
http://i1084.photobucket.com/albums/...EB4E36E300.jpg

I make 12psi at 2000rpm in 5th. Come at me bro.

F2T FTW

I think it should reach 320 either way, so the question is - what do you prefer?
Think packaging, think response, think total torque and power output.

Oh, i wasn't talking about the F2T. That does that in 2nd gear.

The tubular manifold will shine up top. It will add a little spool time but usually its negligible.

At your power levels a tubular manifold would be a wise investment. Beyond that you need to determine the number you will honestly be happy with.

The suggestion on pipe size above is a good one but if you want to make much more power than you have mentioned (and be happy with, even just for a dyno run) you will likely need the larger pipe size. Think of it as a larger a/r turbine housing, but for your manifold. Slightly reduced spool for high end flow. Again, that comment is for pipe size, not manifold type.

In theory a tubular manifold with a good collector should spool faster than a log manifold. 1.25" sch40 shouldnt start to choke off till ~400-450whp worth of exhaust gas flow. So it really should be the choice for every T25 flanged tubular manifold beside one for an EFR7163.

https://www.miataturbo.net/build-thr...-thread-59615/
this is my manifold and I love it lots.

I had Abe (ARTech) make me a top mount for my EFR6258. It looks like this with Swaintech coating.

https://www.miataturbo.net/attachmen...ine=1403196572

I didn't notice any lack of spool even running 8.5 compression and a slightly ported hear (both of which are theoretically not good for spool speed). Boost comes on nice and early and STRONG.

The collector will make a difference in top end, but the volume of the small log manifold will flood to the turbo quickly because it has nowhere to go. I should note, when I say spool I mean the time it takes from when you hit the gas to when the system goes from vacuum to 0psi as well as starting to build boost. Not hitting a target boost. Everything becomes constantly variable when trying to hit a target boost- all drawing back to operating load and the limiting factors in each persons setup.

Theoretically with horsepower vs pipe sizes you mention, you are correct.... But remember your thread where we said that theory doesn't always work out in reality? ;) I have some different numbers, but yes a t2 housing can get to be a restriction as well around there. ;)



Nice manifold. Your running small diameter pipe. You would have had slightly slower boost response than if you compared to a log, but again its not really noticeable when your driving. It would be less than 200rpm's difference. I reiterate: when I say spool I mean the time it takes from when you hit the gas to when the system goes from vacuum to 0psi as well as starting to build boost. Not hitting a target boost.

All manifolds posted look good

Although I'm leaning towards Soviets but with longer cylinder 1 & 4 tubes going into a standard 4 pipe T25 collector like Absurd flow use

Is there any data to directly compare Soviet's tubular short pipe to say the ramhorns ?

Lloyd

Kind of, do the math on the volume difference of the 1.5" sch40 log manifold and a 1.25" sch40 tubular with 12" long runners, and then figure out the mass flow on an N/A miata engine and see if its even worth caring about.

Shit

So what do we call Soviet's?

A flow directed log?
Or a short tubular?

Show me yours

Soviets is a shorty unequal length tubular. I misstaed once that it was a "flowly log" manifold and got my pee pee slapped. For reference a flowly log below.

https://www.miataturbo.net/attachmen...wayne_mani-jpg

Ben has a 2554R, not an EFR.

It's not an EFR, so it's not actually relevant to your discussion. I just like stalking Leafy. Sorry for shitting up your thread. :rofl:

lol no worries

I ran a GT2554 at 14 psi on an HKS log. It hit real hard but did struggle at the top end like a MP62 ;-)

I've been thinking there's so many factors going on.

Manifold volume
Pipe diameter
Number and bend radius of gas direction changes
Package space
Downpipe location, number of bends etc
Cost
Power goal

Its between an equal length ram horn or flow directed collected very short unequal length tubular

I have some 1.25" schedule 10 stainless 304L cast elbows that I'm going with. Quality is good and a machined manifold to head flange from these dudes: Exhaust Head Flange - Mazda - Mazda Miata 1.8 Exhaust Head Flange

I wouldnt use sch10 stainless. I'd contact BMC race to get that same style manifold you linked but custom made as 304 stianless and to the pipe size you're using.

I have an Artech ramhorm manifold with my EFR 6258. I made 315WHP @ 12PSI and 323WHP @ 14PSI on a Mustang dyno in El Paso, TX (approx 4000' elevation). I also have a 3" exhaust and 2.75" intercooler pipes with a Precision 600 intercooler. This a a mild steel manifold, not SS.

315WHP and 251TQ at around 12PSI (179kPa)
https://www.miataturbo.net/attachmen...d-sam_0272-jpg

323WHP / 262WTQ @ 14 PSI
https://www.miataturbo.net/attachmen...psf01030ba-jpg

There was a problem with my manual boost controller in the second dyno. I could have made more power. I'm now running EBC.

Moar pics of manifold

https://www.miataturbo.net/attachmen...ps91430744-jpg
https://www.miataturbo.net/attachmen...d-109_1188-jpg

https://www.miataturbo.net/attachmen...d-p1020016-jpg

https://www.miataturbo.net/attachmen...d-p1020018-jpg

https://www.miataturbo.net/attachmen...d-p1020023-jpg

https://www.miataturbo.net/attachmen...d-p1020031-jpg

Ok what in the world is up with the wildly different EFR numbers?

Wo
That is some manifold. Nice welding on that.

Its almost like with the EFR6258 your forced to go top mount to keep the PS..

I'm hoping to retain it with a tight to head canted orientation similar to Soviet's

The problem is the BW turbo's are a mile long and to clear the body your forced to do unpleasant things

Lloyd, I have power steering with the manifold I have. but my power steering pump is trunk mounted.

B nice to see a data log on those numbers, I'm no ware near that HP/PSI ratio.

I got in touch with ARTech and ordered the same manifold & downpipe as Swimming108: https://www.miataturbo.net/build-thr...llo-efr-77075/. It looks very, very similar to what Mazdaspeeder is running.

These are Swimming108's pics, not mine:

https://www.miataturbo.net/attachmen...92284694_n-jpg

https://www.miataturbo.net/attachmen...ine=1389965431

According to Abe, nothing needs modification to fit this manifold. Its both PS and AC compatible, and should require no modification to the mixing manifold.

Interesting enough, I need to get in touch with Abe as I can't remember if I ordered mine in 1.25 or 1.5. Swimming's looks like 1.5?

https://www.miataturbo.net/attachmen...14706989_n-jpg

Anyway, I honestly don't think it'll make that much difference with my 6258. I'm not shooting for SovietPower™ on the top end. Dem throttle response y0, et cetera...

My manifold IIRC was built by Abe on the specs of 99MX5's manifold. Except I retained PS, pretty sure he did not.

I believe it is sch40 mild steel runners with both flanges being SS, with 1.25" runners.

https://www.miataturbo.net/attachmen...ine=1403270082

https://www.miataturbo.net/attachmen...ine=1403270082

pre-coat
https://www.miataturbo.net/attachmen...ine=1403270082

post-coat
https://www.miataturbo.net/attachmen...ine=1403270082

https://www.miataturbo.net/attachmen...ine=1403270082

If you want more photos let me know. Here is a link for the coating: http://swaintech.com/race-coatings/r...aust-coatings/

Also just as a personal opinon, with the kind of power the EFR turbos make, you'll be hard pressed to notice a difference between a log or ramhorn maniflold, for most people anyway.

I think you would notice.

I have used both types that I built. The results in this writeup feel accurate from what I had to do to the fuel map in my car.

http://www.full-race.com/articles/Bs...st_writeup.pdf

That's a good link I read it

It's a compromise then between whether you want the power low or high in the rev range. Bit like the ar ratio on the turbine housing

300rpms for 50fltbs? Seems like an easy choice. AND its not like the tubular setup was making less power than the log even though the tubular wasnt completely spooled because it was making the same power with less boost.

Very true Leafy very true

Damn it! I've got to buy more elbows lol

if you order them from somewhere not local, get more than you need. one miss calculated cut and if you don't do a lot of these you might end up with an elbow less than you need.

just voice from someone who has done it. ;)

Now I stock a bunch of them.

Ok I made something... its a short unequal ramhorn

Volume is about 550cc. Wanted this as small as possible to keep spool good but not limit flow. Angle changes are kept to a minimum. Cylinders 2 & 3 have very little angle change. Cylinders 1 & 4 are as large radius as possible.

http://postimg.org/image/4b4qfhli5/

http://postimg.org/image/7xajs4rvh/

http://postimg.org/image/7cvipfyn1/

http://postimg.org/image/tarzj8dnh/

Stainless MIG welded, she isn't pretty I know

Good show, probably better than I could have done. :bigtu:

Time to bust out the dremel and kill some of those weld boogers, last thing you want to do is push those into the turbine. Also, lets get a shot of the inside of that collector.

interesting design.

is that going to clear the steering shaft? looks like it will be super low

Doesnt look that much lower than mine, if at all. I'm more worried about how far away from the engine it is and if its going to clear the frame rail. Like mine is this close to the frame rail.

Attachment 184846

And this close to the engine block

Attachment 184847

Holy hell margin rape WTF?

Its RHD...

Compressor housing is about 40mm off the sub frame. I had to move alot of stuff. PS pipes (reservoir and pump feed), and get the water pump outlet modified. The frame rail lip was also cut back and re-welded.

http://postimg.org/image/m1b0e9ogt/

View image: P1010633

http://postimg.org/image/4pf96kkd9/

http://postimage.org/image/qd47h0krh/

View image: image

http://postimg.org/image/7nc809s0t/

Its been cleaned and smoothed internally as best I can with a long reach die grinder

thats cool
you RHD guys have it so good not having the steering rod there, so much more room for downpipe

I had to get my mixing manifold modified, an unmodified inlet would contact the manifold. Unless he changed the design recently, there have been 2 others that have had to do the same. It's not that big a deal, Abe modified it for me.


https://www.miataturbo.net/attachmen...219_191345-jpg

https://www.miataturbo.net/attachmen...219_191356-jpg

Yep. I asked Abe and he said there was a minor revision and should have no problem clearing the manifold. I should know more in a couple weeks! :party:

Progressed it a bit today

Slotted the actuator bracket and bent the actuator arm so I could keep the actuator away from the chassis rail and fine tune its position.

Also a few more collector pics
View image: P1010772

View image: P1010774

View image: P1010768

View image: P1010765

View image: P1010764

https://www.miataturbo.net/attachmen...ine=1405325933

https://www.miataturbo.net/attachmen...ine=1405325933

https://www.miataturbo.net/attachmen...ine=1405325933

https://www.miataturbo.net/attachmen...ine=1405325933

https://www.miataturbo.net/attachmen...ine=1405325933

Weekend's working fitting and welding up the downpipe

The Borg Warner turbo turbine V-band isn't a standard v-band design. So I had to modify the eBay purchased one. You cannot source the BW v-band flange or clamp here. The turbo company sold me a Vibrant flange and clamp and that didn't marry up either.

I know it's been a while for this thread, but I want to chime in about my manifold design. I wanted to get the most power pulse scavenging effect from the engine firing order. Notice that the 1-3-4-2 firing order in my manifold occurs in a circular order in the manifold collector. It was a feature I wanted in my manifold, as for the difference in power, I do not know how it compares to the offset firing order in the collector.

My manifold:
_ _ _ _
(2,4)
(1,3)

Others:
_ _ _ _
(1,4)
(2,3)

https://www.miataturbo.net/attachmen...d-109_1188-jpg

https://www.miataturbo.net/attachmen...ine=1403270082

Yup, I too went circular on purpose.

Really doesn't matter. There is enough back pressure in the turbo manifold to offset any type of flow caused by rifling if the firing order in an open scroll manifold.