The old cut up manifold into trumpets idea

[Marco22]

Hi!
I’m going the s54 itb route instead of the cut up oem single stage one! I’ll have to figure out the runner length and plenum size/shape. Does anyone tried? How to find the optimal length for the power etc..

[Dru128m]

I never got to point of needing to optimize. I vaguely recall, trying to do the math poorly, the optimal runner length was quite long, like 20 inches. That's probably wrong. In general, the shorter runners are for power up top, longer down low.

[MOD.Works]

Originally Posted by Marco22

Hi!
I’m going the s54 itb route instead of the cut up oem single stage one! I’ll have to figure out the runner length and plenum size/shape. Does anyone tried? How to find the optimal length for the power etc..

Do you mean that?

[Raimund]

Originally Posted by tree233

I'm curious how light the n54 intake is.
Does anyone have a 3im & n54 intake that they can weigh?

I have an e30 which I stripped back in the day. I was able to remove over 100kg and the acceleration and cornering increase was amazing! So was the NVH tho hahaha

I'm resisting the urge on my 1er, but if I can find enough liveable things to remove or replace I'll do it.

The n54 intake manifold is 4lb lighter than the 3si. I weighed them when i switched

[tree233]

You bloody legend. Cheers

[mindspin311]

Rabid racing is releasing their S54 ITB adapter very soon.

[spidertri]

That's pretty cool, looks like he made it for a team building a race car - RMP Motors

Their info from the comments:

Originally Posted by rmpmotors

we were able to get to over 320whp on N52 on ITB’s

Originally Posted by rmpmotors

built motor, no valvetronic, stand-alone , no maf . Upgraded custom cams and dry sump. It was a full race car.

[mindspin311]

Ya the recipe is a bit different that what you or I would do. But I bet it sounds amazing.

[aznbo187]

Originally Posted by mindspin311

Rabid racing is releasing their S54 ITB adapter very soon.

Nice to see part of the hardware is there. I'm very interested in doing trumpets. The N52 is just a tad too smooth and civilian to me. I hope someone continues the R&D to make this happen. I have my car available for R&D in Denver, if needed.

[mindspin311]

I think the biggest hurdle will be the 128 DME controlling the S54 throttle actuator. Then from there making sure the MAF/MAP signals are correct?

[rjahl]

Originally Posted by mindspin311

I think the biggest hurdle will be the 128 DME controlling the S54 throttle actuator. Then from there making sure the MAF/MAP signals are correct?

MAF is easy, go with MAF less tune
MAP , if you have a way to install one, just use the same sensor used by the MSV70 or MSV80.
Don't know about the throttle controller.

[aznbo187]

On second thought, how do trumpets work when the N52 doesn't have individual throttle bodies? How does the engine know what the throttle angle is? And does that mean the runners are 100% open all the time? Would that explain why the Dru's scenario only ran good at wide open throttle?

[Dru128m]

We where trying to keep the valvetronic functioning as the individual throttle bodies. They where just open trumpets all the way to the intake valves. With no MAF/MAP sensors, controlling the fueling was an issue we couldn't get past on the stock dme.

[aznbo187]

Originally Posted by Dru128m

We where trying to keep the valvetronic functioning as the individual throttle bodies. They where just open trumpets all the way to the intake valves. With no MAF/MAP sensors, controlling the fueling was an issue we couldn't get past on the stock dme.

I'm not too familiar with valvetronics, but I'm assuming using the closed valves as "throttle plates"?

And have you considered using a piggy back fuel controller? Lastly, with that S54 adapter, I wonder if a complete S54 manifold would work instead of trumpets only.

[Dru128m]

Valtronic is just variable valve lift on the intake side meaning your intake valves become the throttle bodies.

There's undoubtedly ways to make it work, I was trying to make it an easy budget diy since all the hardware was built into the head. Buying throttle plate adapters, s54 throttle bodies and fuel controllers was never the plan.

In the end it was a thing I had to try, but wasn't going to throw a ton of money at. If I was a fluent at writing computer code I'd still be trying to crack it. Physically it's all there and works brilliantly, no need for extra parts. The only real problem is the DME.

[Blau]

Originally Posted by Dru128m

Valtronic is just variable valve lift on the intake side meaning your intake valves become the throttle bodies.

There's undoubtedly ways to make it work, I was trying to make it an easy budget diy since all the hardware was built into the head. Buying throttle plate adapters, s54 throttle bodies and fuel controllers was never the plan.

In the end it was a thing I had to try, but wasn't going to throw a ton of money at. If I was a fluent at writing computer code I'd still be trying to crack it. Physically it's all there and works brilliantly, no need for extra parts. The only real problem is the DME.

Why not try out MegaSquirt?

[rjahl]

Originally Posted by WeShallCallHerBlau

Why not try out MegaSquirt?

It's not really a computer DME issue. The MSV80/70 is really well suited and programmable.

The problem is the time required to develop the specific air flow maps.

[MOD.Works]

Testing fitting and testing that everything works. If I was running without a MAF or TB, I could have done a better intake box modification. There is very little space. I'm not entirely happy with this, I would have liked an e46 M3 CLS style plenum. Trying to get the OE 130i euro air box in place. This hot air filter and MAF was temporary, with which I tested that everything is ok.



Also the N52 oil filter housing is a problem when using the S54 Plenum. I went the easy way and modified Plenum. If I get better results than the N54 intake with this setup, I'll try moving the OFH to make room. Also MAFless tune, so I can move the TB forward and into the right position.

[tree233]

Dang that looks sweet!! Pretty close to done
It's nice to see you making progress!

[MOD.Works]

Originally Posted by tree233

Dang that looks sweet!! Pretty close to done
It's nice to see you making progress!

Thank you.

This s54 mod needs more research and maybe the next version. I think this would be a little better if it had an S54 CSL style or even a stock S54 intake elbow. Now the 1 cylinder runner is in really bad shape and it's like around the corner and the 3 4 5 and 6 cylinder is in a better position.

Next I'll go back to the N54 intake I'll try to go with that. Now I got a peak power far too high, compared to others who drive N54 intake. The power rises even above 7000rpm. I have a limiter of 7500rpm, I think it could be higher. It could also be that my exhaust makes a difference. It also made a difference to the stock 3IM and I lost a little power in the about 5200-5700rpm range. I got more over 6300rpm. The exhaust is easy to modify if that's a problem.

Belows a fun little comparison. I have smoothed out the curve shapes. I have a bit of a bumpy road. Everything has been driven the same way, etc. Since I had no other data 3IM pull. I'm looking for a new place where I can run an even comparison between S54 and N54.

[tree233]

I'm looking forward to seeing that! Even with the current plenum it looks like you'll have gains.

Could you run a panel filter behind the headlight to give you more room, so you can move the intake elbow forward on the plenum?

[MOD.Works]

A panel filter might give more space. A MAFless tune would help me the most, then I could leave the MAF off.
I haven't asked StageFB yet if that would be possible.
I can test the MAFless tune with the N54 intake if it is possible to get the tune from StageFB.

Below is a comparison of the S54 airbox and 3IM. Don't stare at the numbers, they could be anything because the virtual dyno.
I just want to see the difference in the curves and where there is a drop and more power. The same specs and the same road were used, and the weather was almost identical in both WOT runs.
The car felt better today than before because I've driven a little more and the DME has adjusted. I did a clearing of the adaptations before the previous WOT run. Since I previously had a custom MAF housing, I changed back to the OE housing and Filter. The OE MAF housing works better.


Blue=3IM, Headers, MILVS, SuperSprint middle section and muffler. Stock front pipes, no cats. Mr5/Dinan intake mod and K&N filter. Stock tune.

Red= S54 airbox. New exhaust system, only the headers are the same as before. And other mods are the same as before.
+StageFB N54 tune.


The S54 airbox doesn't lose torque in the low and mid RPM range as much as the N54 intake does. In addition, the S54 airbox makes a similar resonant sound as if the 3IM Disa valve were broken, the resonance is loud at approx. 3000rpm. The N54 intake does not do this.
I think the 3IM and tune would still be the best option for a daily car. I could get a little more power in the 3IM if I had a StageFB tune for it as well.

I also have some thoughts and experiments with the N54 manifold. I'll try that first.