Twincharging in "reverse" Order

1198 Views 14 Replies 3 Participants Last post by Quick86, Apr 23, 2022

Quick86

Discussion Starter · Apr 21, 2022

I had an idea for another 3800 build recently, and can't get it out of my head. Besides the added complexity and expense of moving air from the M90 to a pipe outside of the intake, what else would need to be considered for reversing the order of the M90 and the turbo? I wondered if a larger bypass valve would be needed to keep from choking out the turbo. Are there any other factors I'm missing?

Rectangle Schematic Font Parallel Engineering

I know this probably sound like a silly pipe dream, but I love the twin charging idea. I also love the insane whine you get from putting the throttle downstream of the supercharger and chopping off the inlet. Speed is never my #1 priority. I just like fun goofy builds. Of course the instant gratification of the M90 and the turbo to pick up where the M90 leaves off has always interested me too though. You would no longer have the throttle blade between compressors, but I think you would need to control the big bypass valve so that it opens when the M90 stops being efficient or the plumbing becomes an inlet restriction for the turbo. I'm guessing compounding would be out of the question since the smaller compressor is upstream. Right? It would certainly be a big fabrication job, but fabrication is the fun part IMO.

What do you think? Is it dumb? Am I missing or wrong about a bunch of important bits?

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dezldave961

· #2 · Apr 21, 2022

Look up the guys who did the up side down M90 build recently for an example of ridiculous wasted effort for inefficient results, yet respectable work input.

If you want, go buy the Mace Air to Air intercooler plate for an outlet. It is the worst way to route a positive displacement blower, since they need to pack air in the volume below them to create pressure... Hence our short path to the LIM and heads after the M90, and majority of roots blowers intercooled with sandwiched plates or short paths with cores inside, like LSA/LS9 lids.

www.maceengineering.com.au

52MM AIR TO AIR INTERCOOLER PLATE TO SUIT L67 SUPERCHARGED 3.8L V6

Product no.AA601,Harness the full potential of your L67 supercharged V6 commodore with this unique air-to-air intercooler adaptor plate.

www.maceengineering.com.au

www.maceengineering.com.au

Font Auto part Metal Automotive wheel system Carmine

90's Thunderbird Supercoupes had something similar for their Eatons, and you hear all the crickets from how those performed.

Enjoy.

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Quick86

Discussion Starter · #3 · Apr 21, 2022

dezldave961 said:
Look up the guys who did the up side down M90 build recently for an example of ridiculous wasted effort for inefficient results, yet respectable work input.

If you want, go buy the Mace Air to Air intercooler plate for an outlet. It is the worst way to route a positive displacement blower, since they need to pack air in the volume below them to create pressure... Hence our short path to the LIM and heads after the M90, and majority of roots blowers intercooled with sandwiched plates or short paths with cores inside, like LSA/LS9 lids.

52MM AIR TO AIR INTERCOOLER PLATE TO SUIT L67 SUPERCHARGED 3.8L V6

Product no.AA601,Harness the full potential of your L67 supercharged V6 commodore with this unique air-to-air intercooler adaptor plate.

www.maceengineering.com.au

View attachment 11557

90's Thunderbird Supercoupes had something similar for their Eatons, and you hear all the crickets from how those performed.

Enjoy.

I was basing a lot of what I was talking about on that build. Lol So you think the long intake is what's causing the lack of boost? To be honest I didn't know that the tbirds really had any performance issues. I just knew they were a lot less responsive to upgrades.

Quick86

Discussion Starter · #4 · Apr 21, 2022

Yeeeaaahhh... I did a little googling on positive vs non-positive displacement pumps and learned pretty quickly about what all that means. The blower would be pretty worthless in this kind of scenario. Dang

Turbocharged400sbc

· #5 · Apr 21, 2022

2300cc screws are too small. 3300 or 200ax whipple with say a 108mm big t4 guy with dirrect port foggers just in case it doesnt explode fast enough (the trans that is)

god dammit where's jdredd im curious how the whipple cars been since he got it

Quick86

Discussion Starter · #6 · Apr 22, 2022

Turbocharged400sbc said:
2300cc screws are too small. 3300 or 200ax whipple with say a 108mm big t4 guy with dirrect port foggers just in case it doesnt explode fast enough (the trans that is)

god dammit where's jdredd im curious how the whipple cars been since he got it

I miss all the wild and crazy builds. Few people seem to be documenting them anymore.

dezldave961

· #7 · Apr 22, 2022

Jdredd has been having issues with TEP Dave, from what I heard recently. I guess the rebuild on his turdblo racecar turned into long term storage, and not sure what the JonBob's car's status is now.

As for trying to use PD blowers to boost large volumes of air, that's why guys with Air-Air setups on them (Aussies with Mace kits, Thunderbird SC's, upside-down man, etc.) need to spin them to the moon with tiny pulleys to get any performance bump, making plasma from the outlet while trying to do so.

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Quick86

Discussion Starter · #8 · Apr 22, 2022

dezldave961 said:
Jdredd has been having issues with TEP Dave, from what I heard recently. I guess the rebuild on his turdblo racecar turned into long term storage, and not sure what the JonBob's car's status is now.

As for trying to use PD blowers to boost large volumes of air, that's why guys with Air-Air setups on them (Aussies with Mace kits, Thunderbird SC's, upside-down man, etc.) need to spin them to the moon with tiny pulleys to get any performance bump, making plasma from the outlet while trying to do so.

Good to know. Now that I kind of have a grip on what PD means, I can finally drop my goofy idea. As much as I want to do something with the Gen V in my basement, I can't come up with any ideas that particularly excite me unless it involves another engine platform. It's probably time to sell it.

dezldave961

· #9 · Apr 22, 2022

You could do what I may do for kicks, and ease off the perpetual reaching for max effort, and start doing different build config's for the challenge and such... turbo with different cam setups, different gearing, blower with different IC and cam combos, etc.

Maybe I've been staring at my inventory of 3800 mods too long, and just want to have fun with what's in the collection. Saves some money rather than going out to build the same turbo/TH400/6.0LS in a Fox/SN95 or G/Fbody, etc. to have the same "experience everyone else has now... and for 3x the price of playing with the toys I already have. I'm sure I'll get into something with more pep later, but it's still entertaining to me with these for now.

Quick86

Discussion Starter · #10 · Apr 22, 2022

dezldave961 said:
You could do what I may do for kicks, and ease off the perpetual reaching for max effort, and start doing different build config's for the challenge and such... turbo with different cam setups, different gearing, blower with different IC and cam combos, etc.

Maybe I've been staring at my inventory of 3800 mods too long, and just want to have fun with what's in the collection. Saves some money rather than going out to build the same turbo/TH400/6.0LS in a Fox/SN95 or G/Fbody, etc. to have the same "experience everyone else has now... and for 3x the price of playing with the toys I already have. I'm sure I'll get into something with more pep later, but it's still entertaining to me with these for now.

That was more or less what I was dreaming up because I have a pretty set goal for the Camaro, and it's close to being reached. It might need a smaller or ball bearing turbo to bring the power down low (hence my twin charging idea), but neither are probably necessary for the goal I have.

dezldave961

· #11 · Apr 22, 2022

For low end, shortening the charge length with Air-Water, converter changes (for my auto), and longer runners in the Holden seemed to make it non-existent.

Quick86

Discussion Starter · #12 · Apr 22, 2022

dezldave961 said:
For low end, shortening the charge length with Air-Water, converter changes (for my auto), and longer runners in the Holden seemed to make it non-existent.

My charge tubes are quite long and I have a pretty decent intake restriction in front of the turbo too. Thanks.

dezldave961

· #13 · Apr 23, 2022

I know ZZP has some timing cuts in their pocket that isn't openly shared. Granted, you can somewhat figure this out yourself, but our PCM's aren't too flexible for that. Adding a 2-step module (not sure if we can with our specific setups) or buying a $1K+ aftermarket stand-alone with those options are all I can think of off-hand.

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Quick86

Discussion Starter · #14 · Apr 23, 2022

dezldave961 said:
I know ZZP has some timing cuts in their pocket that isn't openly shared. Granted, you can somewhat figure this out yourself, but our PCM's aren't too flexible for that. Adding a 2-step module (not sure if we can with our specific setups) or buying a $1K+ aftermarket stand-alone with those options are all I can think of off-hand.

Ben Styx figured out how to make the WOT box work with the factory ICM. I've actually bought the WOT box and modified my spare ICM to replicate Styx's too. I just haven't been motivated to dive into my factory harness and tee into all the signals. It's one of those things I haven't had time to figure out because I've had too many more pressing issues like drive line vibrations, oil leaks, Ill handling...

Which reminds me that I have no business thinking about a "next project". This current one is probably not as close to done as I think it is. 🤣

Quick86

Discussion Starter · #15 · Apr 23, 2022

I still drool over the idea of a Holley system to get that built in wot box and 2-step, flex fuel, CNPs, and most of all local tuning support.

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