S54 turbo sizing help

[CosmoE36]

Long story short I built my own turbo kit diy style.

- Spa t4 manifold
- Borg Warner s257 SXE 57/62 .83 a/r
- Ebay aluminum s54 intake manifold
- Turbosmart WG45 hypergate 10psi spring
- Tial Q 50mm bov with plain spring
- 3 inch catless down pipe to dual 2.5 y pipe to stock section 1, status gruppe 3 inch section 2 and agency power gen 1 section 3
- 3 inch FMIC
- hpx pmas MAF
- aem 340lph fuel pump
- Bosch 65# Injectors
- Stock mss54hp dme tuning
- 2.25 hotside charge pipe
- 3 inch cold side charge pipe

Modified turbine housing for 44mm wg flange with 90 degree elbow to remotely relocate wg further down stream and routed back into section 1.


When I got my turbo I thought I was being really slick and that because I only wanted 400 or 450 horsepower and thought I would have quick spool with good streetable power.. The turbo I chose was recommended by boost labs because it's rated for 650 horsepower. But everybody who has Turbo s54s has been telling me that the S54 breathes way too much and my turbo is being restrictive.



We had a Disappointing dyno session today and this just confirmed what everyone was. Telling me. My turbo is too small especially on the exhaust side.

My current turbo specs are :

Borg Warner s257 SXE
Compressor:
Borg Warner 3.5" Inlet/2" outlet Ported Compressor Housing
57.15/76.20mm Billet Compressor Wheel w/ Extended Tip

Turbine:
69.56/61.43mm Turbine Wheel
.83 a/r exhaust housing

Hassan Talal Eido with hte tuning did absolutely everything he could to relieve as much back pressure as he could, this guy is a wizard who knows his magic

He looked at the dyno log run files along with the data logs from the runs.

boost was tapering/spiking at 12 psi briefly in the midrange around 4000 rpm or so, and as the engine demanded more air , it can't keep up and boost dropped to 7 psi. Even using a 10 psi spring and a manual boost controller to achieve higher boost, but the turbo just won't flow anymore than that. We tried to relieve the exhaust pressure with some vanos tuning to gain back some of the top end, but we're still limited by the physical size of the turbo, and the engine is just being strangled by the small exhaust housing.

Looks like I need to upgrade to a 6766 or a 6266 at a minimum to allow the engine to breather better uptop, right now as it stands there a lot of back pressure, and the turbo can't flow enough air past the midrange to make good power.

I wish I could just slap on a 1.22 a/r housing on my current turbo bit it's still a gamble.

Here was the best run of the day 393 whp and 373 tq I guess 7psi? hard to say because it's spikes to 12 at around 4,000 RPMs but pretty much drops the 7-psi very fast.

on this run I actually started the Dyno run at 4000 RPMs 4th gear. all the other ones were from 2000 RPMs and 4th gear we did this because we were adjusting the boost controller for a spike and starting a 2000 RPMs with the boost controller adjusted would have caused the boost pressure to go even higher with the spike so we wanted a little less load on this run.

Hats off to Hassan and his professionalism in trying his best to work with what I had.

Overall I'm just pretty disappointed in the outcome of the kit and my turbo choice and it's an expensive lesson learned. I'll just sit on it how it is for now and until I can get some more money to get a different turbo and then also get the exhaust housing modified. That's The real hurdle in upgrading turbos is that any turbo I change to I have to get the exhaust housing modified for the wastegate.


I just want to know if all I want is 450 whp on 93 pump gas.. Will my current s257 axe turbo be capable of doing that if I change the exhaust housing to a 1.22 AR exhaust housing with its current compressor and turbine setup?

Or do I really need to change the whole turbo to a larger turbo such as the precision 62/66 or 67/66?

There is a dyno graph I have attached and here are some links to the in car and out of car session

In car view showing the boost gauge RPM and speed
https://photos.google.com/share/AF1Q...hJT3lvOVBYZUN3

Out of car
https://photos.google.com/share/AF1Q...M0dWdWQnNtRHl3

I feel really stupid right now thinking I could make my own kit that had good power for street driving. Hoping for some advice that can put me on the right track.


And yes I have boost leak tested my entire system. I've tried boost leak testing all the way from my compressor inlet to the intake manifold I could build 10 PSI of pressure but I would slowly bleed off pressure through the journal bearing and my turbo causing my oil to gurgle in the pan and also bleeding air in the ITB throttle plates.

10 PSI would drop down to zero PSI and probably about 20 seconds.

If I pressure test from the hot side piping all the way to the end of the cold side piping it will hold 10 PSI solid no movement...

If I pressure test just the intake manifold on its own it will hold 10 PSI solid no movement.

and lots of people I talk to said yes you will bleed air through the throttle plates with a boost leak test and then also it's normal on a journal bearing turbo to lose pressure through the oil drain flange into the oil pan.

And of course other people say no that's not right but I don't know how to believe these days.

Anyway I don't think I have a significant boost leak. It's just really weird how I can boost either 10 PSI or 12 PSI with a manual boost controller adjustment and it's still always settled back down to exactly 7 PSI by red line.


Thanks everyone

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[M3poseur]

Good job on DIY👍🏼 You should not feel stupid. Respect for doing it yourself.

The HPX maf location are not optimal.

[et89]

Cool build, shitty story regarding the turbo. i am a bit surprised too hear that your 0.83A/R is to small for your S54.
Garrett has a good explanation on how to read turbine graphs on their site. maybe you can use that to help you calculate your problem?
https://www.garrettmotion.com/wp-con...3_Expert-1.pdf

[PowerKraut]

Do you have a boost over RPM graph? I dont see how you spool so late, yet a 0,83 would be THAT restrictive. i'd rather expect that charger to be at 15 psi easily by 3000rpm or so on a 3.2 Liter ... to be honest, i would say swapping to a bigger housing is an easy thing, so maybe just do it.

[NOTORIOUS VR]

Unfortunately 2 minutes with the BorgWarner matchbot would have shown you that the turbo is far too small for an S54:



The S366 or S369 would be a nice fit for that engine though

[CosmoE36]

Unfortunately 2 minutes with the BorgWarner matchbot would have shown you that the turbo is far too small for an S54:



The S366 or S369 would be a nice fit for that engine though

Are you able to explain how to read the compressor map? I still am ignorant and just don't understand the the turbo can be rated for 650 hp but only make 393 for my engine because it's too small.

Is it possible to lower the max rpm in the tune and tube for power with that turbo with a more narrow rpm range?

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[R.Thomas]

Just because the turbo has a nominal rating for X hp does not mean it's sufficient for all engines with a given HP goal that is less than the nominal turbo rating due to variations in engine displacement, backpressure, etc. For example, the turbo needed for 650 hp on a 2 liter, 4 cylinder engine is usually different than that needed for 650 hp on a 3.2 liter 6 cylinder.

[CosmoE36]

I posted a link to two videos One of them is a video showing my gauge cluster that shows the speedo RPM and the boost gauge and AFR. Is anybody able to look at that video and tell me if that boost fall off/taper looks more like a boost leak or like my turbo is choking up top?

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[CosmoE36]

Also if somebody could take a look at the pictures I posted of my wastegate routing solution.

Initially I saw how the maximum PSI kit mounts the wastegate directly onto the turbine housing.. but then I saw how much they had to cut out of the skid plate for clearance so to get around that instead of putting the wastegate on the turbine housing I put a 90° pipe which routed the wastegate further down by about a foot away and then routed the outlet back into the merge collector exhaust y pipe.

Not I'm thinking about it maybe that could be causing my issue? Having the pipe in the wastegate on their turbine housing isn't that effectively increasing the size and a negative way of the turbine housing because now turbine gases are being expelled out of the turbine housing all the way through the pipe to the wastegate which would cause a delay and a spiking?

I'm curious if I should just try taking the waste gate and mounting it directly onto the turbine housing instead and then using a block off plate on my y pipe for testing purposes and running the wastegate and open dump to see if my boost issues get resolved or any better.

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[NOTORIOUS VR]

I posted a link to two videos One of them is a video showing my gauge cluster that shows the speedo RPM and the boost gauge and AFR. Is anybody able to look at that video and tell me if that boost fall off/taper looks more like a boost leak or like my turbo is choking up top?

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The turbo is choking - as I said and (showed you) it's too small for your engine which needs more air then your turbo can supply. This is why the boost drops.

[Colby Colbs]

That turbo is severely hurting volumetric efficiency, that's why. You need a properly sized turbo. Even a GTX3582R is small for this engine and is completely done by 25psi boost. (might make 30psi with gate pinned shut but backpressure is already too high @25 so that's my max setting on c16 only).

[Greenday694]

In failure there can be lessons, in perseverance there can be results.
I think you're off to a good start, especially for a do-it-yourself. but I have to agree with the others, that turbo is too small for your engine. It might work pretty good on M50 B25. The s54 engine breathe very heavy, and requires and overall larger Turbo. Larger housing may help a little, but you will get more lag, and I don't think you will reach your horsepower goal.

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[CosmoE36]

Thank you everybody for your advice and lending your thoughts and confirming what I've been told about the turbo being too small for the S54.

I'd like to stay Borg Warner when I upgrade turbos eventually.

So I'm considering the:

S362 SXE with a 68mm turbine wheel
S364.5 SXE with 68mm turbine wheel
S366 SXE with 74mm turbine wheel


How do any of those sound for supporting an s54 with 8k rev limit and a 450-500 hp number.


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[JimsR]

S366 or S369 as mentioned earlier.

[CosmoE36]

S366 or S369 as mentioned earlier.

Thanks I forgot to read further back I remember seeing that now.

What size exhaust housing would you recommend Is there a maximum number you would not go past?

There is a gentleman locally here in Georgia selling for $650... a s372 SXE 1.0 ar housing 72mm billet compressor wheel, .73/80 turbine wheel.

Is that Turbo just ridiculously overkill for my 500 wheel horsepower goal?

I'm curious at what RPM I can expect to get full spool on the S54 with the 366 369 or 372.

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[NOTORIOUS VR]

372 is not what you want for that power level... and IMO is too big.

a 66 will do 650ish @ the wheels

I doubt you will see much difference in spool between the 66 and 69 - but it's splitting hairs now... and if you're worried about spool/response you can always move to the more expensive EFR lineup

[CosmoE36]

372 is not what you want for that power level... and IMO is too big.

a 66 will do 650ish @ the wheels

I doubt you will see much difference in spool between the 66 and 69 - but it's splitting hairs now... and if you're worried about spool/response you can always move to the more expensive EFR lineup

What about AR size on the exhaust housing... I typically see .91 or 1.0 or 1.15 or 1.22.

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[NOTORIOUS VR]

What about AR size on the exhaust housing... I typically see .91 or 1.0 or 1.15 or 1.22.

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Again, since you're looking at a much lower power level you're not going to be held back with any choice... so if it were me 0.91, or max the 1.0

[CosmoE36]

Again, since you're looking at a much lower power level you're not going to be held back with any choice... so if it were me 0.91, or max the 1.0

Do you know if I'm going to have any fitment problems with the s369 SXE and a SPA T4 manifold on an S54?

I saw several threads the n54335 guys saying that the 369 would not fit different manifold and engine setup.

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[NOTORIOUS VR]

Do you know if I'm going to have any fitment problems with the s369 SXE and a SPA T4 manifold on an S54?

I saw several threads the n54335 guys saying that the 369 would not fit different manifold and engine setup.

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No idea sorry

[Colby Colbs]

I would do a 6674 for your S54. If you need help selecting the right unit I can help, send me a pm.

[CosmoE36]

I would do a 6674 for your S54. If you need help selecting the right unit I can help, send me a pm.

Thanks man after a lot of back and forth I ended up going with the Borg Warner s366 SX-E has a 66 mm compressor wheel and a 80 mm turbine wheel.

The best I could do was just find pictures that did side by side comparisons of the 366 SXE versus my 257 SXE and it is significantly larger so I'm hoping and praying that I won't have clearance problems with the SPA T4 manifold and the engine block.

it's frustrating because I can't believe all the searching I've done all the reading everywhere I look nobody has that combination that has information online so I can't confirm if it will fit with no problem.

I tried making a post on the boost addict forum because I did see one guy on there that has the maximum PSI kit with the 366 SXE Turbo and I asked him if he could confirm which manifold he's using but he never responded and probably won't.

So across my fingers that it will be at least a tight fit.

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[Colby Colbs]

Thanks man after a lot of back and forth I ended up going with the Borg Warner s366 SX-E has a 66 mm compressor wheel and a 80 mm turbine wheel.

The best I could do was just find pictures that did side by side comparisons of the 366 SXE versus my 257 SXE and it is significantly larger so I'm hoping and praying that I won't have clearance problems with the SPA T4 manifold and the engine block.

it's frustrating because I can't believe all the searching I've done all the reading everywhere I look nobody has that combination that has information online so I can't confirm if it will fit with no problem.

I tried making a post on the boost addict forum because I did see one guy on there that has the maximum PSI kit with the 366 SXE Turbo and I asked him if he could confirm which manifold he's using but he never responded and probably won't.

So across my fingers that it will be at least a tight fit.

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It's tight but it will fit.

[CosmoE36]

It's tight but it will fit.

That's the reason I didn't go for the 369sxe... It was only $50 more on full race website for cyber week sale but after looking at pictures I could tell that the compressor housing was larger than the 366 and a 366 was going to be a tight fit then the 369 probably wasn't going to fit it all and I'm looking for something that won't cause me to have to grind away material from the block or compressor housing.

Thanks for the help

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[GG///M3]

Billet 6466 or 4094