Not to be rude, but in those 30 years how many twincharge builds have you done with a centrifugal supercharger?

Explain why Vortech wanted to do the same setup in the Ecoboost? They don’t have much experience right?

 

I didn't completely understand that blurb and nor did I want to invest the time into it and I'm sure I'm missing a bunch of context … I don't care, In vacuum and on paper this may work?? but in real-world, installed on in an already crammed engine bay … ehhhhh, not likely …

I know what Otaku is doing wont produce better results but I also know that there is nothing I can say to change his mind.. (but to each their own)...so it's none of my business what he does

Yea, the dual charger 350z that I recall used the first generation Stillen roots supercharger...where the turbo fed roots style supercharger. This helped quite a bit alleviate the space constraint … I don't know how you make this system better by having 40 feet of 3" charge piping go every-which way...

but if Otaku wants to take it on it's his choice …

 

Went to the shop today and grabbed some valuable info and my tuner came up with an excellent idea.

For now the info will be in under wraps, but he found a way for the turbo(s) to extract air separately until it sees boost pressure and then closes when under pressure. It’s a strangely cheap mod that’ll hopefully work.

This should allow the boost pressure in the piping to build up between the turbo and manifold a lot faster.

The concept is soon being tested with a dual turbo compound 350z setup here as well. I’ll be sure to update the results when I get them but I can’t release too much info.

But really, I wanted to try something interesting. If I really wanted to be boring I would’ve trashed the Z build and kept the Z06. Then we can argue about how stupid building a VQ is compared to an LS.

I hope you see where I’m going with this. I’m not trying to make breakthroughs, just different routes for power regardless if it’s stupid or not. Because if I don’t try it, how long will it be until someone does? Especially on a growingly unpopular engine.

 

There is quite a bit of guessing here and that torquecars article is not something I would trust. With a roots style supercharger, the turbo HAS to go after the supercharger because the SC has a defined maximum flow rate that it will hit and anything after is just extra restriction. This does not apply to your situation with the vortech.

With the vortech you will functionally be the same as having a compound turbo system. One will be for low rpm and one will be for high rpm. The compressor map of the vortech should be used to determine if you want the vortech to be the high or low rpm unit. The low rpm unit goes last, with the outlet going to the intercooler. The low rpm unit will suck air through the high rpm unit before it is spooled. I will use the twin charged mustang for example. The turbos come on EXTREMELY early in those cars, as in full boost at 1800 rpm. as shown below.


With this graph you can obviously see that the small turbo runs out of breath up in the higher rpm and flow rates. This is where the vortech supercharger comes in. The vortech probably starts making more boost than the supercharger around 4500 rpm. Now instead of the boost falling off, the vortech is feeding the turbo high pressure and high flow air and the turbo can overspin allowing that boost to basically blow through and decrease the exhaust back pressure pre turbo. you will need multiple blow off valves before the smaller unit and before the intake manifold.

None of these will mean you can spin the SC slower. You will need to solve your belt issue. People have made substantially more power than you with the vortech. Figure out your belt issue/ go to a cog drive to cover up whatever the issue is.

 

Extremely useful info, I really can't thank you enough. This does make a lot of sense considering the other double turbo twincharged 350Z experiment is using the larger turbo first and then the smaller second.

The pipe routing from the turbo intake outlet to the Vortech inlet might prove interesting.

 

belt issues (as previously discussed) and if you're relying on the supercharger to do the high RPM work you will lose power-to-the-rear-wheels and unless you bypass the exhaust flow around the small turbo charger the turbo charger hot side is the choke point.

If you look at the compound turbo setups of RX7 and MB bi-turbo...they use a small turbo for low RPMs and a large turbo for high RPMs and exhaust gas is directed to each independently. The idea of a supercharger feeding a turbo (if that's still what you're thinking) and thinking you'll get massive numbers above either a supercharger spinning 100k rpm or a properly sized turbo is unrealistic.

 

Like the mustang example, the vortech feeding the turbo will decrease the preturbo back pressure and help lessen this choke point, or a positive pressure controlled wastegate could also be used. It will kill efficiency. Everything about this whole system is horrible for efficiency and I don't recommend a single thing to OP. Its a horrible decision and a properly set up SC or turbo will outperform any of this at less load on the engine. BUT Since he seems bent on doing it, it is an interesting process on how it will interface.

I still agree that a properly sized turbo is a better option. followed by actually addressing the belt issues and getting an appropriate sized blower for the power goals.

 

I hear ya … it's almost like you're powering the turbo charger with cold-side air charge to evacuate/vacuum-out exhaust gas...regardless, a small turbo would use a 2"? 2.25"? 2.5" exhaust pipe...you aint flowing too much exhaust through 2.5" of pipe ...


makes 3 of us...

I'm in for results to see how bad it performs … I hope OP goes through with it … I (respectfully) think it wont...

 

Sorry a little late to the party.

I spent a bit of time trying to figure out how to route such a thing and I came up with some more interesting results.

Rather trying to explain it, I spent an unnecessary amount of time drawing it on paper and then photoshop to trace it out. Don't mind the sluggish drawing but hopefully I can bring in some light.

The one problem/question I'm afraid of, is finding out whether or not the boost will spin the blower faster. It's already known the turbine of a turbo spins far faster than a centrifugal supercharger. Is the RPM only limited by the belt/engine speed or will boost amplify the speed?

If the speed is static with or without the turbo, then it's not an issue of the revised routing. I colored in trouble areas when it comes to intake temperatures and the biggest problem I face is post-supercharger.(Making dense air denser will sure as hell make it a lot hotter since there isn't a lot of travel time for the dense air to cool down during expansion.)

You bought up a good point on how I should feed the supercharger with the turbo, and it brought up several ideas to reduce the piping by probably 35-40% since I'd only need one long intake pipe instead of two. Maybe this will look better for you, or maybe it wont.

Don't worry bealjk, I'm not expecting a miracle, I'm just interested in the results to see what the powerband would look like.

Worse case scenario, I can just remove the blower, toss in one new intake pipe and it'll be converted into a single rear mount with just one pipe replacement. (Maybe two to make fitment a lot easier)

I thought of this placement solely in case the build turns out miserable and I can easily convert to a single big rear. (Rear mounts aren't that great, but I could always replace the blower with nitrous to build boost on the low end.)

Here's the image:

 

One. Which is more than the zero Vortech has actually built.

Vortech wanted to do that for the sake of simplicity. They wanted to add a S/C to the pre-existing turbo setup and didn't wan to re-engineer what Ford had already done. It's your car, you can install a kerosene turbine if you want. Just trying to save you from the "why won't this work" posts later.

I also have some experience with rear mounts. Here's one I helped build... My old roommate's car:

 

pretty picture Otaku ...

so ... this makes a little more sense...

Your supercharger will provide boost 0-8psi / 1000rpm to 3000rpm and around 3500rpm to 4500rpm your turbo will have created positive boost pressure that superceeds the supercharger ... so you have 2100rpm (from 4500rpm to 6600 rpm) to make another 12psi to 14psi (which I'm saying sarcastically) ...

I dont think a rear-mount turbo is going to create that much boosts/airflow, from the back of the car, through an intercooler, and around a supercharger ... a smaller rear-mount turbo wont create the airflow required to out-pace the supercharger and a bigger blower could create that much airflow but wont fully spool until much later in the rev-range.

so your power band will be 4500rpm to 5000rpm (around the peak torque for these engines) and you'll be pushing 14psi to16psi at this point ... which you could have made easily with a belt driven supercharger or a mid-mount or front mount turbo.

The upside is that you'll have 'some' boost from 1500 to 4000rpm, where a turbo you wouldnt quite that early. But just a standalone supercharger would give that to you too.

Also, in the higher revs (lets say 5000rpm to 6600rpm) you are getting zero benefit from the supercharger but you are 'spending' engine torque to spin it (rather than sending it to the rear wheels).

worst of all worlds, your engine is powering the supercharger and gettting zero benefit from it, and furthermore, the supercharger is a restriction on the turbo's charge-air.

 

But it will set him up to run a big rear mount and spray. That is a proven combination for huge power and crazy torque starting as early as you are brave enough to start the spray. So he is just using quite a bit of time and money to get there involving the vortech paperweight.


With what was drawn, you will need an extra bov before the blower. I would also put a meth injector right after the SC to get the temps down since they never see an intercooler. While you have it all apart though you might aswell get the runners machined for spray ports.

 

3500 sounds like a pretty good target for a large turbo quite honestly. I was actually looking into the Comp Air-cooled 7275.

But considering the turbo is spinning from the exhaust back-pressure, and also getting assistance on the intake side from the blower pull. It looks like a lot of pipe, but a Vortech V2 Ti ain't no slouch either. If I had a V3, then I can see myself running into a wall.

Don't forget the reasoning of compound boosting! The supercharger is never useless because it's compounding boost, not adding to it. Sure it's less efficient than if I compounded with a small turbo, but beggars can't be choosers.

Spray was only planned if I have to step up the build (Closed deck block, ARP 625s, girdles, etc) if the engine fails or possibly before depending on how hot IATs are.

But I considered spraying maybe a 25 HP shot for the purpose of cooling only depending on what I'm dealing with. (I'd rather concede to nitrous before water/meth. Personal preference)

Also yes! I completely forgot to draw the second blow off valve but I'll get to it so I don't reference it later and forget to add one to the actual build.

 

at the Comp 7275... I thought my turbo was oversized... Thats a 1200hp turbo... that you want to also compound. I would recommend something closer to the 6262, 6266, or 6267. If you are really shooting for the stars go for the 6767 that is rated for 1000. Turbos have efficiency ranges, and the 7275 would most likely suck until 5000+ on a 3.5 liter even with compounding.

Methanol is orders of magnitude better than Nitrous for cooling charge temps. Nitrous adds heat and means you have to pull timing. Methanol removes heat and makes the loading safer due to the increased equivalent octane.

 

Turbos aren’t anywhere near my specialties. I was basing my choices on the finding something with a better flow rate than the Vortech and going up from there. I might’ve overestimated quite a bit.

That’s why I asked those general questions in the first post. It’s very difficult to make this work the way I’m hoping, but the fun of the challenge is what drives me with this build. Would you also think the 6870 is excessive when the end goal is 1000? Or would you think the blower would limit it?

 

I hope you follow through with this …

So I do these rear-mount kits with a buddy and we use a pretty small Rev9 6262 style turbo … they are small (all things considered) and they start making positive boost around 3500rpm and we can maybe get 10psi or 12 psi before redline. and this is with a 2.25" pipe, he makes around 350hp/325tq. A 7275 will take forever to spool up and if you're running a larger 2.5"? 3" charge pipe, you're never going to overcome compression lag from the back of the car, especially if the supercharger is pulling air from it...your turbo is gonna act like an 'air charge conveyor' …

Yes, the supercharger may be pulling air through the turbo but that's not 'free' … that's additional restrictions and power draw from the crank as now the SC has to pull intake past a turbo and down 16ft-18ft of pipe - no free lunches in nature.

I don't think a vortech / procharger will 'compound' boost like you think...a stillen / eaton roots style will because it's 'sealed' / positive displacement … if the procharger belt was disconnected but the turbo was still going, you could run your engine … the turbo would simply push charge air past the impeller... if you had a roots style blower, the turbo wouldn't push air charge past the blades if the blades were stationary - i8Cobra brought this up earlier and I think you glossed over it - I think this is the assumption that defuncs your build.


you wont see anywhere near 1000hp … g'd I hope you do! A system like this with how complicated and how inefficient you are, all in my opinion, will see 500 to 600, how ever hard you can push the supercharger is the most power you'll see. The rest of parts are simply a restriction and a power-rob.

But lets see it happen!

 

Never know unless I don’t try right?

Ill be heading to the shop tomorrow to measure the distance between the pulley and volute so I can determine the biggest pulley I can fit. Crossing fingers that I can fit a 3.25” so I can just order it right away. Otherwise I might have to just get a custom sized one.

Hypothetically, if nothing goes wrong, I might be able to get dyno numbers within the month of June. Then at least we’ll have a base number and graph to work with.

 

*edit* copy

 

I can appreciate your positive attitude and willingness to attempt it...

you're not 'hypothetically' building this ... you're building this in real-life and in real-time...

plan on many things going wrong...not because you have a flawed design basis(which you do, IMHO), but because things go wrong...I dont know how many things went wrong on my front-mount build and because I had time, space, and a little extra money I was able to mitigate each problem.

give em hell! prove me wrong!

 

Oh, I'm using hypothetically in terms of when it'll be completed. There can always be random small road bumps that can stall time.

Thanks! It'll either be great, or terrible but fun regardless.