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SC 330 compound boost build Twinscrew/T72 turbo

58K views 325 replies 58 participants last post by  cyberlando 
#1 ·
I am currently rebuilding my engine for a compound boost set up. I made this decision after damaging my supercharger by running meth and nitrous!!!!! :facepalm:Huge no-no. The water froze and pretty much acted like stones in the supercharger, deep scratches and funny noises followed.:thumbdwn:

So in my quest for more go fast I decided to rebuild something insane, so here we go...:thumbsup::woot:

Whats done/what I have...

M30B54 ported head
Cosmetic mls head gasket (lower compression)
ARP studs
Custom camshaft (260/268)
ESS twinscrew supercharger 1.6
Custom 88mm throttle body
Custom intake
Okada plasma lift (on back order)
Ceramic header and heat wrapped
Custom pulley
800cc Bosch injectors
255 lph fuel pump
Fuel regulator
Secondary air delete
Nx express nitrous (75hp)
Nx express methanol kit stage 2

ZHP 6 speed conversion
4.10 LSD
ZHP short shifter

And lots of other parts not directly related, gauges, etc..

I am ordering a T72 turbo for a rear mount set up. I will be running 8 psi on th SC and 9 psi on the turbo. My concern is the tuning and any equipment that would make my life easier.

PLEASE UNDERSTAND...I am looking for positive feed back of known issues and experiences, or known related issues of the build. I say that to say I'm not interested in how stupid the build is....thanks. All comments are appreciated.
 
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#226 ·
I tried, I failed!!!!! :banghead: One misfire is all I needed (even though it's because of the plugs) its too risky after the time and energy oh, and money :banghead:


I need to find a professional with FIC experience in My area. :(

I am gonna get the exhaust done for the turbo. I need to be able to swap the turbo and muffler back and forth. Not hard..the performance muffler shop is walking distance from me, so that's a plus. I'll drop it off on Monday. I wanted to mount the oil cooler, but I can wait. I anticipate having the compound boost set up in the next 2 weeks.:bump:

I'll post pics tomorrow....:clap:
 
#227 ·
ok, getting close to the finish line....:woot:i had an exhaust leak at the header that was causing the idle issues (it appears) because it has a steady idle now.:thumbup:

I have sketched 2 different set ups for the rear turbo. attached. One pic feeds straight into the turbo but i would have to craft a exhaust pipe with ah crazy bend since the exhaust side would be facing the center of the body. The other would keep the exhaust side facing the back, but the exhaust tube would be at a 90 degree angle, im thinking this will slow volocity. So im still deciding...:tsk:

I am going to order 2 resonators, the car is WAY TOO LOUD even at 2k rpms. I am desperate to tone down and quite the car. :shhh: I researched that the larger the diameter of the resonator, the quieter it will be, so i have my eye on a 4 or 6 inch diameter resonator.hopefully with the turbo also muffling the exhaust it can be tolerable because with these 4.10 gears i stay in high RPM's. :eek:

last items to purchase:
oil pump and oil lines
k&n filter RX 4130-1 (slim filter direct bolt to turbo)
Exhaust tips

(euro oil filter housing which isnt needed, but nice to have)

Then its off to the DYNO :evil::clap::evil::clap:

I looked back through this thread, it has come along way since my engine in pieces on my garage floor, and time wasted waiting for other people to do what i was able to do with some elbow grease, sweat, and the internet!!!!:read:
 

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#229 ·
Once you put the turbo on, the car will be much much quieter as it's a muffler on its own.
 
#230 · (Edited)
Its not going to quiet it down as much as you might think when its a rear mount. but it will some, just not as much as a front mount.

but then this is going off 2 identical gto's one with a single upfront and one with a single rear, but same exhuast size etc no cats no mufflers. same boost, same turbo etc etc
 
#231 ·
I agree that the turbo wont do much, i dont think it will quite it more than the muffler. Im thinking that mounting it so the exhaust port is facing sideways and then customizing a "S" pipe t exit the current location would produce the most baffle, but then the concern is limiting the turbo with the s pipe...

Sent from my DROIDX using Bimmer App
 
#232 ·
My recommendations is to join the manifolds/headers into a 3-4 inch pipe bring it straight back bending to where the muffler will be removed. Then off the turbo using a 2-2 1/2" max pipe all the way either to your intercooler or charge pipe.
 
#233 ·
Charge pipe

Yea, that's what I'm doing. U can see my crude drawing above. I wanted the exhaust to flow straight into the turbo, but i think the curved exhaust pipe would have limited the turbo. So, im gonna do dual into a single with a 90 degree turn into the turbo. It turns single about 9 inches before the turbo. I'm just trying to work out the exhaust tips. I need the flage that attaches to the exhaust side of the turbo to weld the exhaust pipe to. Working that now.

I have an idea for the charge pipe so I won't have to reduce the size of the intake tube. I don't want to limit my bottom end performance. The idea is to feed the 2.5 in charge pipe into the 3.5 inch :pimpin:intake pipe via a "y" weld. Ill put a boost actuated cut out on the intake side to close once the turbo begans to boost.

This should be interesting....:pimpin:
 
#234 ·
Ill put a boost actuated cut out on the intake side to close once the turbo begans to boost.

This should be interesting....:pimpin:
You won't see "boost" from the turbo until after that valve is closed.

The only accurate way to do this is to measure turbine speed, and base the valve closing on that. I'll warn you though....measuring turbine speed is a very expensive proposition....I'm going through this now.

My recommendation is to forget about that valve and run all of your air through the turbo.
 
#241 ·
...I don't think it will work that way, scientifically.

theoretically, Lets say the intake is drawing 100 cfm of air (just to keep the numbers round) through the 3.5 inch tube the MAF would see 100 cfm. Once the turbo begans to builds boost it will create more air than the 100 cfm that the TB is drawing. At that point the 3.5 in tube is closed (because if u don't the air will escape your filter) and all incoming air is from the turbo...there is no lag in air, just the constant increase that the turbo would create anyway....
 
#242 ·
I'm talking about the MAF being the issue. It reads x amount of air but the range will only go so far up or down. To optimize tuning you'll need to scale the MAF tables wide enough to allow it to read the amount of air it draws in as well the amount of air that will be forced in. Scaling the MAF tables to do both seems to be a bit much but I know very little about tuning if you can say I know anything.
 
#244 ·
Ritos, you are correct, but I'm going to have to do that anyway because the set up is already going to move more air than the MAF can measure. That's where the FIC and tapping the MAF comes in. I'll have to set the MAF clamp to the highest reading or voltage the MAF can handle, then allow the FIC to tune for the additional air.:D

PEI330, you and I obviously have 2 different approaches to problem solving. And though we have the same hobby goals of creating a fast non-m BMW, we also have 2 different approachs on how to make our cars fast. To take it a step further, we have differing ideas on what parts will make a car fast. You have your way and you have hit your peak HP numbers based on your knowledge (as you do seem to be knowledgable about theses engines). But...you have not broken the 600rwhp on the M54 from what I have seen. With that in mind, you can give definately give your opinion and I welcome your insight on the issues and what you have experienced. My choosing not to follow your advise isnt personal, just my personal choice. Hopefully you can continue to be supportive and provide some valuable insight because everyone is welcome on my thread. But if the fact that I don't share your approach is offensive, then I apologize and understand you just wanting to wait to see where the build ends up.

By my calculations, I have the foundation (sc/t72) to see over 600rwhp. Now I just have to hope that the engine can handle it. Some followers say yes, some followers say no....in the end, it will be what it is! ;)
 
#245 ·
PEI330, you and I obviously have 2 different approaches to problem solving. And though we have the same hobby goals of creating a fast non-m BMW, we also have 2 different approachs on how to make our cars fast. To take it a step further, we have differing ideas on what parts will make a car fast. You have your way and you have hit your peak HP numbers based on your knowledge (as you do seem to be knowledgable about theses engines). But...you have not broken the 600rwhp on the M54 from what I have seen. With that in mind, you can give definately give your opinion and I welcome your insight on the issues and what you have experienced. My choosing not to follow your advise isnt personal, just my personal choice. Hopefully you can continue to be supportive and provide some valuable insight because everyone is welcome on my thread. But if the fact that I don't share your approach is offensive, then I apologize and understand you just wanting to wait to see where the build ends up.
I think you missed what I was getting at.

A turbo can flow 600whp of air at 0 PSI if no restriction is placed across the outlet. By using a sensor placed between the turbo outlet and the primary air filter, it is very possible you will not see enough positive pressure to activate the valve. If the signal source was plenum pressure, which would be highly influenced by mass flow through the SC, I think that could work.

As to what I have or have not done, I'm pretty open with it all. I get asked for help from a wide range of people starting at the inexperienced hobbiest, all the way up to professional race teams, and even on occasion, people working on post graduate studies. (Masters or Doctorates in Engineering) What I don't know myself, I usually have a contact I can ask that can point someone in the right direction. Sure people can have different approaches, but I find the science of this hobby a common absolute.
 
#246 ·
So I'm at my shop this morning digging through my shelves for a part....and I find a custom ATI Harmonic damper I had built for the race car. Here's the thing, it has a 6.8" 6 rib pulley on it.

If you run into issues with belt slip on the SC.....give me a shout. Changing to a larger crank pulley will allow you to run a larger SC pulley which will help with belt slip. I've also got the drive mandrel for a dry sump pump that mates to the ATI damper as well....
 
#247 ·
interesting thought, what's the actual size difference between the stock and the 6.8"? I have to be careful going larger on my pulley because the 11 psi pulley is only seeing 5 psi of boost:hmm:Still scratching my head over that one. I knew it would drop after porting and the larger TB but that was surprising but works out great for the project.

I would be interested in the damper for the ability to rev higher with the turbo (of course I'd upgrade lifters as well). What's the down side to the ATI?
 
#251 ·
Uhhh it's not. It's just risk management of a series of events, and an understanding that something is going to break. :eeps:The reward is being able to enjoy the car before it does.:clap: Then the excitement of knowing if it breaks it's a chance to make it stronger and ultimately faster.:evil:

Some of us will never meet our HP goals because the darn line keeps moving everytime u get close!!!!:lmao: and then there is this ridiculous belief that the car can take just a little bit more....well, u don't have to be a rocket scientist to know where that ends.:banghead:

PEI, no rush...I surprised u even replied. I get drugged for everything the dentist wants to do...even a cleaning :D
 
#253 ·
I haer you, but u just completed your grade. ;) I bought my ess ts2 in 2009. It was great then, but then i realized how much i was missing :) this time around i wanted something insane. Ive done just about everything there is to do. Gears, trans swaps, nos, meth, etc...this was the only option for me. You can never have enough boost....
 
#258 ·
Getting a custom exhaust fabricated today. Didn't plan on it, but when I removed the rear section of the muffler and measured the diameter of the dual pipes I learned that it was only 2 inches. :yikes:I was surprised because it was a full Borla exhaust that I purchased years back. That may even explain some of the choking I was experiencing down low.:eeps:

So now for the new exhaust. Research is indicating that the max HP on 3 in single is roughly 400 HP. Dual 2.5 is roughly 500 HP. :read: The problem, it has to single into a three inch to feed the turbo. If I dual 2.5 from the header to a 3 in single, say midway, aren't I still limiting the system as if it were a single 3 in exhaust? :hmm:

If the answer is yes, then I might as well do a single 3 in all the way back.

:idea: As of now I'm thinking the best set up would be dual 2.25, yes 2.25, with dual resonators (thinking the resonators will slow the flow as much as a dual 2.5 inch setup will) into the 3 inch. Quiet is king for me. I know this will choke off on high HP for regular turbos but not sure how a rear mount would respond. Also, I'm trying to maintain balance because the less exhaust flow the more lag the turbo would see.:hmm:

I'll be dropping the current exhaust off this evening so I have a little time to try and figure this out...:facepalm:
 
#259 ·
I never had a problem making 600+whp on 3" turboback exhausts.
If you go with resonators use the perforated cores versions and not louvered cored as those slow down exhaust velocity.
 
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