twin charging - wastegate, bov, routing

[kinger]

Boring in here so lets start some discussion! Bringing back this thread from 2011 so you know I have had this idea forever and its time to act!

Twin charging make sense

Snow is gone so brainstorming begins on sled for next year. Got to thinking about adding a turbo to my sled with the SC. Basically lower compression to 8.25:1 with pistons and shim, flip the pulleys on my stage 1 to run 5-6psi, then get a stage 2 turbo system running around 16-17psi total...

ty4stroke.com

Short version: I have a impulse apex (crashed) , I have a SC apex (with new built motor) - Boosting it to the moon and need advice on how and where to run vacuum/boost lines

Long version:
Ok so if you read my garage thread you know I had a SC apex and loved it. Bought a Impulse mountain apex and converted it to a crossover sled and loved that more, then promptly crashed that and went back to the SC sled that was half way parted out and joined the two sleds together to make one good one. The 'good' one had a engine oil leak that I could NOT figure out. I thought the block was cracked so I bought a built motor from Ulmer Racing, I then promptly dropped that while unloading and bent the waterpump. I yanked the water pump off my old sled and bought a rebuild kit for it on eBay and promptly found that my oil leak was the seal inside the water pump. So engine #1 was still solid and is a shimmed stock motor. uffda... Anyway put motor #2 in the old SC apex and broke it in Iowa style by flying over roads and ditch banging within a inch of its life and loving every minute of being back on a boosted apex after my disaster with the BRAND NEW sidewinder... uffda again..

So now I have my old apex beat chassis rocking a new built motor that is properly (and I say that loosely lol) broke in with the SC running 10 psi of boost. This is a 9:1 motor so even at 10 psi its soft compared to a 10:1 set up. I did that for a reason because now I add the turbo..mmmwwwhhhaaaaaa! (that said in my best halloween scary voice)

So after now 10 years since I first proposed the idea to myself in the thread above.....I have determined that I will use the Impulse turbo to feed the inlet of the supercharger, which will then compound it and turn it into.. MO BETTA. So a few things I am thinking about, I have a Tial external wastegate on the race impulse kit, I have a vortech blow off valve on the intercooler, and I have a Motec ECU. I am looking for advice on how to connect all this to get what I want.

Here are my thoughts and what I want you badazz engine turbo racers critique for me.

Hook the Tial, and BOV together behind the TBs
T into the boost line from Tial WG to go to the boost control solenoid on the Motec
Tap the IAC sensor into the IC so I get compressed air temp (it gets zip tied in engine bay with the MPI)
Use Motec closed loop boost control to monitor knock, IAT, and adjust boost up or down automatically with the turbo WG only

Or should I seperate the WG and the BOV and T them into different parts of the boost like the outlet of the TC, SC, etc.

I want to build in protections for motor when WOT for long periods. My hypothesis is my Stage 1 MPI IC is not going to be adequate at 20+ PSI for 30+seconds so when the IAT climbs I will have the Motec pull boost but I want to validate this before I add a new IC as the MPI is really lightweight.

I also want the turbo to make a little boost while cruising to help reduce the mechanical load the SC creates and hopefully extend my fuel range. I am always out of fuel LOL

Thank you guys! Please give me your feedback!

 

[MrSled]

Boring? Makes me sad.

 

[kinger]

Boring? Makes me sad.

Blame the Sidewinder, its always my go to now (LOL) , they stole all the aftermarket boost forum talk!

Now lets build some twin charged madness and fire me up!

 

[MrSled]

Blame the Sidewinder, its always my go to now (LOL) , they stole all the aftermarket boost forum talk!

Now lets build some twin charged madness and fire me up!

Right!! That will be a HOOT to drive that TWIN turbo animal. I would think you should be able tee the lines into the other turbo vacuum at the throttle bodies.

 

[zx4ever]

Well kinger you have had 10 years of dreaming about this. Let’s see what comes of it. Man this twin charging sounds so complicated but will be so cool once it’s worked out.

 

[MrSled]

I wish you were closer to me Kinger, I would love to be part of that beast!!

 

[kinger]

What WG spring makes sense? I get confused when I want the turbo to be making “assist” boost while cruising that gets blown off by the bov but I want the motec to be able to run the TC to zero if it detects knock or high iat. I don’t think the boost taps can be in the same spot?

 

[kinger]

I'm going to leave 7 psi spring in the the WG, tap it into the IC, it will always see boost then open at 7 psi so I run on the SC only. Then use the closed loop boost solenoid to up total manifold pressure to 22 psi, cut back to 10psi from SC only. The CR is so soft I think I could get by on 87 octane and 10 psi with the knock retard strategies you can employ in the Motec. This will be my "limp it home" mode should I get bad fuel or run out of Torco. I'll start here. I expect to re-do this 5 times before I get all this to play nice together.

 

[Dan Lance]

Are you using a Rotrex supercharger?

 

[kinger]

Are you using a Rotrex supercharger?

Yes sir!

 

[Dan Lance]

So you’re using a rising rate centrifugal supercharger with a rising rate turbo charger? Seems a waste. A properly sized turbo can accomplish the same thing minus all the extra weight and parasitic loss. Now if it was a screw type compressor that provided instant boost, that helped spin up a larger turbo that keeps going when the supercharger runs out of flow (rpm tethered) it would make sense. If you’re doing it just for fun and the look at me factor have fun with it. I’m sure it will look impressive!

 

[kinger]

The SC makes boost at clutch engagement or dang close. At 6000 rpm in a trail it always in boost. That’s what you can’t get with the turbo. You can get it close but not perfect. I really want the 30mph - 70mph snap in the trails. This will do it. Then compounding up to 29 psi across a lake. In theory what you say makes sense but with this motor and combo this will give the best of each…I’m hoping lol. Also hoping that by feeding the SC the turbo will reduce some parasitic drag. I had both from wrecked sleds so it was fun to play with. Using the Motec electric boost control will be killer in the midrange. Again on paper! Open to advice!

 

[Dan Lance]

 

[mbarryracing]

I don't think Kinger is building this as a dual charged parallel system like in that video, but more so a compound system (one into the other) where a turbo is feeding a centrifugal supercharger which will result in that SC producing more boost.
It's nto as uncommon as you might think. You see this in modified tractor pulling, especially with V12 Allison Aircraft engines that have a built in centrifugal SC guys run big turbo's off of each bank feeding it, 2 into 1.
Also I believe Detroit Diesel might have also done this on a 2 stroke truck engine from the factory. In any case, pretty common in the diesel world.
Is it overkill? Yes.
Is it needed? No,.
Is it something unique to play with on a sled? Heck yeah...

Merry Christmas

 

[Dan Lance]

In the video the turbo feeds directly into the positive displacement sc. Thats the whole point. Yes he could do the same as he’s doing now with a large/small compound turbo set up, he’s just using the crank to spin the small turbo instead of exhaust gasses. That’s all a centrifugal sc is is a belt driven turbo, but with a fixed boost limit. Max engine rpm will be max boost on the sc, with boost rising in proportion to rpm. I agree that people will certainly think it’s cool but from an engineering and application point of view it’s not viable. I like seeing 8 little turbos on a v8 etc as much as the next guy, not finding fault.

The blower on a 2 cycle Detroit added no boost, the engine couldn’t run with out it. It wasnt until the turbo was added that it made boost