M50 vs sheet metal intake manifolds for high hp applications

**wgknestrick** · 02-24-2021, 12:38 PM

Does anyone have any first hand experience with hp gains in a custom sheet metal (ideally the supra style, end inlet) over the M50 manifold? The M50 is a decent OEM manifold, but I suspect the center inlet and small plenum volume is causing a restriction as you get north of 600hp or so.

**R.Thomas** · 02-24-2021, 01:07 PM

The following is from a recent post in the Boosted E36 FB Group for a "back-to-back" dyno comparison on the same engine with the same boost pressure:

> Stock cams & stock intake - 550 hp

> Cat cams & aluminum intake - 611 hp.

The post did not include a dyno run with just the intake or just the cams...

Interpret as you will.

**Colby Colbs** · 02-24-2021, 01:20 PM

There was about a 40hp gain if I remember correctly but there are variables so you don't want to get hung up on exact numbers.

**someguy2800** · 02-24-2021, 02:27 PM

I have not dyno'd my current setup but I went from an M50 manifold to this one. I also changed cams from 280/264 vac cams to 276/276 enem cams, and also changed from a .90 to a 1.20 exhaust housing. With the M50 manifold and vac cams it made 830 whp at 34 lbs of boost through a 3 speed auto and torque converter. Power was falling off at 7800 rpm. With the new manifold and enem cams the airflow is still climbing at 9000 rpm according to the ecu data. Going off of trap speed I would estimate the car picked up about 150 whp at the same boost.

The billet runners are from GDM engineering, and I made my own sheet metal plenum to save money.

**wgknestrick** · 02-24-2021, 07:28 PM

I think 30-40hp is about what you would expect, but it seems we don't have any single variable dyno results.

**someguy2800** · 02-24-2021, 07:55 PM

Originally Posted by wgknestrick

I think 30-40hp is about what you would expect, but it seems we don't have any single variable dyno results.

Boost will multiply whatever the motor makes NA. If you can pick up 30 whp NA, which I think would be easily achievable on a larger displacement motor with good cams, then it will pick up 60 whp at 1 bar of boost, and 90 whp at 2 bar of boost, ect... The gains will continue to multiply as long as you can keep the intake to exhaust pressure close to 1:1

**someguy2800** · 02-24-2021, 08:01 PM

As I noted on my car I changed 2 other things at the same time, but I went from trapping 151 mph in the 1/4 to hitting the rev limiter at a little over 160 mph at the 1000 foot mark. That’s a big f@&?!g difference. I will note though that this isn’t just a straight tubular runner, there is some real proper engineering in this manifold. Not just replicating the stock manifold in aluminum like some.

**wgknestrick** · 02-24-2021, 08:46 PM

Your runners are super short though and only for top end HP. You stated you changed, cams, exhaust housing, and intake manifold though. I agree that it is a big improvement, but your car is a bit of an extreme drag case compared to mine. IMO, you probably picked up the most hp from the exhaust housing swap, but it's hard to discern with 3 variable changes all at once. There is no way an intake manifold is going to pick up 30whp on a M50 manifold on a NA setup. It would be great if we could, but I don't see it happening. Boosted at 3x the NA hp level, yes 30-50whp possible.

I am tempted by some of the Ebay manifolds as they actually don't appear to have any significant WTF decisions on them. Note, I am referring to the ones with equal length runners, not the WTF ones with unequal length runners. They have manifolds with 14" runners or so, velocity stacks in plenum, but I'm a little concerned with the stupidly large, 90mm throttle body. Has anyone tried one of these yet? It's certainly not bad for the money. I wouldn't expect it to be turn-key and there is probably some omission that needs to be welded on, but it's a great start from what I see. Al > 25yo fiber filled nylon in my book.

https://www.youtube.com/watch?v=MsgqdW7zrvE

Side note:
If anyone is itching to go through the "Everything on Ebay is shit" rant, just stop now. I don't want to hear it unless you've used it, first hand. We all use Ebay intercoolers, silicone hoses, catch cans, seat covers, radiators, etc now. Everything is made in China.

**someguy2800** · 02-24-2021, 09:04 PM

Your nuts if you thank changing a turbine housing picked up 15ish mph trap speed. An intake won’t pick up 30 whp on an otherwise stock NA M52, but it’s entirely possible on a motor that really needs it such as a 3.2l with ported head and a healthy cams. An interesting experiment would be to put an m50 manifold on an S54. You offered no detail of any kind in your post about what you have, what you want, where you want it, or anything else so I’m just giving you the info I have and you can make what you like if it.

**Colby Colbs** · 02-25-2021, 10:15 AM

The ebay manifolds are horrible. Total junk. Don't waste your time or money.

**wgknestrick** · 02-25-2021, 10:20 AM

Have you actually used one and which design are you referring to? There are several different. What was horrible about it?

**Colby Colbs** · 02-25-2021, 11:11 AM

No, it was unusable. Everything about it was just bad. The runners were different lengths. The whole pattern was off and it was nowhere near flat. I wouldn't ever recommend it. A crappy intake manifold is a huge fire hazard.

**lbennyboobool** · 02-25-2021, 12:26 PM

what custom manifold would you recommend?

Perry want to make some plenums for everyone?? JK

**SilburE36** · 02-25-2021, 06:40 PM

Is the intake manifold flange available anywhere, as either a fabricated part, or a CAD/CAM file?

A 3D printed piece could then be cast from aluminum, and the rest welded up.

Seems I lack a laser scanner at the moment.

Sent from my iPhone using Tapatalk

**someguy2800** · 02-25-2021, 09:09 PM

PPF in Sweden sells a cnc manifold flange with injector bungs if you want to make your own

**m3j0n** · 02-25-2021, 09:45 PM

Originally Posted by someguy2800

PPF in Sweden sells a cnc manifold flange with injector bungs if you want to make your own

thank you

**james wright** · 03-22-2021, 03:10 PM

Hi I'd like to liaise with you abt an M50 build I'm doing and what cams to use. As well as the timing blocks you make. Can I link via Facebook? Regards.

**someguy2800** · 03-22-2021, 03:51 PM

Originally Posted by james wright

Hi I'd like to liaise with you abt an M50 build I'm doing and what cams to use. As well as the timing blocks you make. Can I link via Facebook? Regards.

Yeah, Perry Hubbling on facebook.

**zemaestro** · 03-25-2021, 10:11 AM

I have billet runners available for sale and you can fabricate your own plenum as Perry did...they are $1500 with fuel rail and require removal of oil filter housing. I have that part available as well.

**wgknestrick** · 04-27-2021, 01:38 PM

I think I'm going to pull the trigger on this Ebay special now that I have a good CF Nylon 3D printer to design/fab parts to solve any blunders they may have made. It looks like a good starting point/$:

https://www.ebay.com/itm/20298844642....c101195.m1851

I'm definitely going to design an adaptor to fit the stock TB back onto it because the 90mm it comes with is WTF large.

**ba114** · 05-02-2021, 09:14 PM

Originally Posted by wgknestrick

I think I'm going to pull the trigger on this Ebay special now that I have a good CF Nylon 3D printer to design/fab parts to solve any blunders they may have made. It looks like a good starting point/$:

https://www.ebay.com/itm/20298844642....c101195.m1851

I'm definitely going to design an adaptor to fit the stock TB back onto it because the 90mm it comes with is WTF large.

I have already designed and printed an adapter in CF Nylon to fit an N62 throttle body to this

**Colby Colbs** · 05-02-2021, 09:27 PM

That thing is such a POS. Belongs in a garbage can.

**milKt** · 05-03-2021, 06:50 AM

It is gonna LOOK so good.

FashionFold.

**wgknestrick** · 05-03-2021, 10:24 AM

Originally Posted by ba114

I have already designed and printed an adapter in CF Nylon to fit an N62 throttle body to this

Do you mind sharing a STEP file? I have SolidWorks 2021 if you have a native CAD file too. It would save me a little time measuring and would be something to work from. I'll share back what I end up with (and add an Oring groove that you are missing for sealing the stock TB). I'm assuming you added brass, threaded inserts for the TB bolts in the adaptor or did you just drill/tap the AL IM flange?

Love all the "un" biased haters posting shade with zero information to reinforce their opinion on something they have probably never held, worked with, or tested. Had the same type of people 20 years ago about only paying $300 for an intercooler vs $1500 from a "known" tuner brand. Same damn cores. Either add something to the thread or move on. We don't want your "Not going to work" attitude. Tell us why it belongs in the garbage. Show me a dyno of before/after.

**someguy2800** · 05-03-2021, 10:38 AM

Until I see someone actually test one of the ebay manifold I am not going to push an opinion of it. Someone needs to convince whoever is making the N54 ebay manifolds to put an M50 manifold flange on them instead. That looks like a nice little manifold.