Jump to content

75 2002 Sleeper - M20B32, ITB, LSD


Recommended Posts

Back on the '02 topic...  Since you are running ITB's, have you thought at all about what kind of plenum you will be running?  I've been doing some looking around and even the most high tech applications seem to be using a very simple design.  The one common aspect I do keep seeing is that the plenum tapers quite a bit to the last intake port, I.E. furthest from the plenum inlet.  I assume this is just to keep the velocity high and minimize turbulence.  

I've been looking to do some CFD on it but my SolidWorks only allows one inlet and one outlet calculations so I am trying to run it on OpenFOAM.  I'd be very interested to see what you come up with. 

Link to post
Share on other sites
  • Replies 301
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

So knowing what my wheels and tires were going to look like, I've had the idea in the back of my mind that the turbo flares weren't really going to cut it anymore. So I've been slowly adding to my met

No progress on the car this week, I've been fabricating some equipment for the shop (to use on the car!). I did want to share two things though.   First up, I made a facebook page for my "company"  

Hey thanks, I'll look into the fuel pump. Also, the carb does have an air cleaner it just happened to be taken off when I took the picture.

Posted Images

Nice!! You definitely have more active projects than me! It seems like you have more time as well. Love the floor space. I am in the process of finishing a 1,500sqft workshop so that I can start a 2002 M3 SMG (donor car) transplant into my 1976 BMW 2002. Your metal fabrication work is very impressive! It has inspired me to step up my abilities, hopefully I'll get there. Great diaries on your projects, we all look forward to the next one!  

 

Thanks for the kind words. I'm lucky enough to have the time and resources to take on what I have. I hope your going to start a build thread for your project, it sounds like it should be pretty great when it's done. I'll be curious to see how you shoehorn the S54 into the 2002 engine bay, I toyed with that idea for a while but decided to stick with the M20. By the time I'm done it should be putting out a bit more power that the s54 :).

 

 

Can I now tell you that I hate you and wish I never saw this thread.. Thanks for making me the most envious person on this board Not thanks, Pete Edit: that was jealousy talking! I've had the pleasure of driving a 27k mile e28 m5 and it changed my life. That car will bring you joy, no doubt.

 

 

Back on the '02 topic...  Since you are running ITB's, have you thought at all about what kind of plenum you will be running?  I've been doing some looking around and even the most high tech applications seem to be using a very simple design.  The one common aspect I do keep seeing is that the plenum tapers quite a bit to the last intake port, I.E. furthest from the plenum inlet.  I assume this is just to keep the velocity high and minimize turbulence.  

I've been looking to do some CFD on it but my SolidWorks only allows one inlet and one outlet calculations so I am trying to run it on OpenFOAM.  I'd be very interested to see what you come up with. 

 

You are correct, the reason for having the plenum taper off towards the last runner is due to the desire of keeping the charge velocity high. Of course this only applies to plenums that have the intake at the front. If you look at other plenum designs where the intake charge enters in the center it is a completely symmetrical design. My initial design will most likely follow that of the e46 CSL airbox. a quick google search will show that it too follows the tapered design. Mine will most likely be made out of aluminum, but the same idea still applies. 

That being said I also have some other ideas that I want to start developing if time permits. Afterall, the ITB's are only as good as the flow of air before and after them. There are many more gains to be had.

Link to post
Share on other sites
You are correct, the reason for having the plenum taper off towards the last runner is due to the desire of keeping the charge velocity high. Of course this only applies to plenums that have the intake at the front. If you look at other plenum designs where the intake charge enters in the center it is a completely symmetrical design. My initial design will most likely follow that of the e46 CSL airbox. a quick google search will show that it too follows the tapered design. Mine will most likely be made out of aluminum, but the same idea still applies. 

That being said I also have some other ideas that I want to start developing if time permits. Afterall, the ITB's are only as good as the flow of air before and after them. There are many more gains to be had.

 

I must admit that I've taken your ITB idea for my own application on my M42. My 1200RS throttles just came in the other day.

 

Anyways, I find it interesting that you're looking to the S54 airboxes for inspiration, but it makes sense since you've got two extra cylinders. I've found that the S14 DTM boxes are very representative of what would work quite well in the 02's, considering most M2 guys are using them anyways. I don't believe the S54 style would fit quite as well as the S14 would, since space is pretty limited in the 02's bay. Another aspect of the S14 box that has caught my eye is the curvature of the runners, as seen in this picture:

img0868wc.jpg

 

This design seems to peak and then drop back down into the plenum, which would allow for longer runners. We'll want to have just about the longest runners we can swing due to the fact that these engines won't be revving very high, and runners that are too short in length will really hurt midrange numbers.

 

But, now that I think about it, it may be hard for you to implement the S14 style box in aluminum. I would imagine shaping the runners would not be an easy task, especially since they have so much taper to them.

Link to post
Share on other sites
Afterall, the ITB's are only as good as the flow of air before and after them. There are many more gains to be had.

My thoughts exactly. 
I don't know how courageous you are, given the type of build here I would say quite, but I've been having thoughts about maintaing air velocity and minimizing inlet resistance (low plenum pressure) at both low and high rpms and came up with some ideas...

How about what I like to call a VSL or Variable Stack Length system.
It would pretty much be based on engine rpm.  The intake stacks inside the plennum would change length.  Short stack for low rpm and high stacks for high rpms.  All you would really have to do is just pull them away from the fixed stack and push them close when needed.
A couple pvc pipes, a stepper motor, a little linkage, and an arduino hooked to your CPS could be all you need. 

The result would (I think) give you the volocities needed at both low and high end of the motor.  You could even get crazy and change the fuel injection point at higher rpms for a better Stoich mixture.

 

Just a thought.

Link to post
Share on other sites

It's an interesting idea. I know of a few FSAE teams that made something like that for their cars. Basically they made their 4 velocity stacks in 2 pieces, a top and bottom plate. The top plate would slide in and out to match the ideal runner length to the engine's rpm. Though incorporating a system like that with enough change in total length to be worth the effort would be difficult while still keeping it under the hood. 

 

I've also though about making a circular runner that would rotate via a stepper or servo motor, changing it's length inside the plenum while not actually taking up more or less space. I just need to look into the effect of the runner length vs. the total plenum volume to see if they would cancel each other out. 

 

Oh, and I think you meant longer runners and low rpm and shorter runners at high rpm  :)

Link to post
Share on other sites

Ok, not to pirate the postings but where can I get:

 

The carbon fiber intake (I you don't mind asking $$ too)

 

Justin

the CF intake in the pic is on an S14 engine in an E30 M3.  looks like one of the versions from MAXX automotive in Germany.   cost is north of $1k.

 

 i have the S14/2002 model in my car.

 

DSC_0246.jpg

Edited by mlytle
Link to post
Share on other sites
. Another aspect of the S14 box that has caught my eye is the curvature of the runners, as seen in this picture:

 

the curve also allows the airbox to clear the hood..... ;)

 

John at MAXX makes several versions of this airbox for E30 M3's to mate to the different diameter TB's available for the S14 and in different runner lengths (limited by whether the stock E30 brake booster is there or not).  the one i have is the S14/2002 specific version that clears the tii brake booster and the strut tower.

Edited by mlytle
Link to post
Share on other sites
  • 1 month later...
  • 4 months later...
  • 8 months later...
  • 3 months later...
  • 8 months later...

Your build interested me to the point I read it hungrily from begining to end, even referencing back to it a time or two and encouraged me to get off my ass and out to the shop to get mine to driving condition...please continue this madness!!

Sent from my SM-G920P using Tapatalk

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.




×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.