Supercharger/turbo setup....

[TT_NS]

all right guys i got an interesting setup. i drew up two diagrams for the 1g dsm with a supercharger and a turbo. one is more basic then the other. on the first set up i have the turbo connected before the supercharger. The reason for this is that it is a simpler set up. You would not half to worry about "back wash" if you would. The idea behind this set up is that the supercharger would simply suck air threw the same intake as the turbo. giving the engine boost while the turbo is taking its time spooling up. then when the turbo spools up it will increase boost. Although i find this a really crapy set up . There would be so much air friction going on in this. First from the turbo being in the way of the supercharger and visa versa. So i thought id try something a little more interesting. Then i came up with the second diagram. In this one the supercharger has its own intake which will reduce friction. But this is where i run into a problem. When the boost being created transfers from the supercharger to the turbo i need to release all pressure being created by the supercharger so i can close off that entire area with a valve that will prevent the turbos pressure from being pushed back out the supercharger. Make since? Dose any one know of a anything that works like a BOV but releases under certain pressure? Any way the pressure from the turbo will shut the valve to the supercharger. hope you can picture how that would work. I was also thinking for either application i could fabricate a pulley or use the one off the A/C on the car so the Supercharger could be turned off and on by a clutch just like the A/C. Although i wouldn't have any idea how i could control the relay from turneing off and on without me hitting a button. that might be to complex for me. I noticed if you take out the A/C you have plenty of space for a Vortech supercharger in that area. That is my plan. Its nice to come up with something a little different then what other people are doing. Just another way to get the power so please don't bash the idea. But let me know some ideas you guys come up with. This would take allot of fabrication but im up for the work.

 

[RayPeters]

So how are you keeping it below 30psi?

Boost controllers..... 2 of them..... 1 for the turbo to keep it from doing anything rash, and 1 on the supercharger to manage max boost, used more as a safety right now. If I break the bypass door open, the multiplication of the supercharger is lessened.

 

[RayPeters]

It was on a 4G63T motor (7.8:1 compression). Took off the turbo and tried the supercharger at around 10psi. Apparently worked well but it wasn't as fun and impressive when compared to the turbo set-up.

Geared right 10 psi from the supercharger should be better for auto X and the like, but for top end the turbo is the way to go.

 

[tsiturbomm]

HAHAHHA thats the only use for a supercharger. TURBO FTW!!!

 

[Defiant]

That's the short short version. I bypass the supercharger under several conditions, it mostly is used for low end punch to get the turbo going. Then at high rpm I bypass to limit power to what the engine can handle.

Ah! Now I feel better about the whole thing. I'd love to see what jimcrackery you've gibbered up in there.

 

[nightspeed87]

You got it, the turbo feeds the inlet of the supercharger, which multiplies the inlet pressure by the rpm ratio of the drive. The supercharger displaces 1 liter of air per rev and has as effeciency of ~75% so there are some losses in all this. The engine displaces 1 liter per rev as well, so to drive it at 1 to 1 would only pump as much air as the engine can use. to drive it at twice engine speed results in 1.5 liters of air being forced into the engine per revolution. 3 times engine speed is just outside the rated max rpm of the supercharger (18,000 or so) but for the math, 2.25 liters of air per rev. Now compound all this with the turbo, it can achieve 3 to 1 pressure ratios as well, so "in theory" it is possible to have a 6 to 1 ratio. now lets convert this to boost pressure,

Givens
14.7= atmospheric pressure
75%= supercharger effeciency

so

2:1 ratio = 14.7*2=29.4*75%=22.05-14.7 to get pressure above atmospheric = 7.35 psi
3:1 ratio = 14.7*3=44.1*75%=33.08-14.7 = 18.375 psi


now watch how scary this gets:

2:1 ratio turbo with 2:1 ratio supercharger
75% effeciency on both

2:1 ratio turbo= 14.7*2=29.4*75%=22.05*2(2:1 ratio supercharger)=44.1*75%=33.08-14.7=18.375psi boost. not scary but keep reading

3:1 ratio turbo=14.7*3=44.1*75%=33.08*2(2:1 ratio supercharger)=66.15*75%=49.6125-14.7=34.912 PSI now were getting someplace

and ...

3:1 ratio turbo= 14.7*3=44.1*75%=33.08*3(3:1 ratio supercharger)=99.225*75%=74.41875-14.7=59.71875 psi This will damage something.... but man would it feel good till it did


So if everyone is still with me, that's how this all works, and keep going with the questions, I appreciate your interest.

Im not great with math but it kind of makes sense considering the turbo is at a set pressure and the supercharger is not. I suppose this is why you get such high boost levels.
So are you implying that this limits how high you can rev since a supercharger is based off a pulley type design limited to engine rev, youd be increasing boost out of your control if you rev beyond your specified point. I noticed earilier i believe you said you were limited to reving at like 6k or something correct?
Say you could rev this thing to 9k what would that translate to?
(Im trying to keep up.)

Also in a recent thread about a 3.5 in exhaust , Ive noticed you stated you run a 4in exhaust. Is this 4in exhaust on this twin charger engine? I suppose you couldnt go too big on your set up considering your always in boost .

 

[RayPeters]

Im not great with math but it kind of makes sense considering the turbo is at a set pressure and the supercharger is not. I suppose this is why you get such high boost levels.
So are you implying that this limits how high you can rev since a supercharger is based off a pulley type design limited to engine rev, youd be increasing boost out of your control if you rev beyond your specified point. I noticed earilier i believe you said you were limited to reving at like 6k or something correct?
Say you could rev this thing to 9k what would that translate to?
(Im trying to keep up.)

Also in a recent thread about a 3.5 in exhaust , Ive noticed you stated you run a 4in exhaust. Is this 4in exhaust on this twin charger engine? I suppose you couldnt go too big on your set up considering your always in boost .

The supercharger isn't an rpm dependent device, it produced roughly the same pressure ratio across its rpm range. The limit for me is the engine stregnth. I limit the boost of supercharger, and I rev limit at 6.5 because I don't want a yard sale . The supercharger has a rpm limit around 18,000 rpm, but 3 times engine speed puts me at 6k limit. 2 to 1 like I am now means 9k engine rpm is doable but I'd need some better internals in the engine to try it. I hope this helps

The exhaust is bigger than it needs to be right now, I was looking at buying 3" and found a supply of 4" so went with that. I'll put it to better use with the new engine.

 

[nightspeed87]

i see... Yea i was under the assumption that superchargers gained more and more boost the higher you rev the system since youd be technically spinning the pulley faster I suppose. Maybe I had a different type supercharger system in mind ( like centrifugal supercharger style instead of roots style. ) Or maybe there all the same I dont know.

Have you ever thought about applying this twin charger set up to your 3kgt Talon for laughs Probably would be more involved id imagen...

Keep us posted with some further pics and dyno information between the two cars,
and Id still like to see pics of the 3kgt talon.

 

[95TalonOwner]

Keep us posted with some further pics and dyno information between the two cars,
and Id still like to see pics of the 3kgt talon.

+1, it's nice to see someone that has done something different and actually knows what they are doing.

 

[RayPeters]

i see... Yea i was under the assumption that superchargers gained more and more boost the higher you rev the system since youd be technically spinning the pulley faster I suppose. Maybe I had a different type supercharger system in mind ( like centrifugal supercharger style instead of roots style. ) Or maybe there all the same I dont know.

Have you ever thought about applying this twin charger set up to your 3kgt Talon for laughs Probably would be more involved id imagen...

Keep us posted with some further pics and dyno information between the two cars,
and Id still like to see pics of the 3kgt talon.

A paxton or other centrifugal supercharger builds boost as rpm increases. The eaton is a positive displacement device, so it is linear ie same boost pressure across rpm range.

Actually I have given it some thought, but I have no idea where I'd put the thing, have you ever seen a 3kgt engine compartment?? I've dropped wrenches into my engine bay it took me almost an hour to get out. I seriously have 2 or 3 wrenches with a hole drilled in them to tie a string to for retrevial.

 

[tsiturbomm]

A paxton or other centrifugal supercharger builds boost as rpm increases. The eaton is a positive displacement device, so it is linear ie same boost pressure across rpm range.

Actually I have given it some thought, but I have no idea where I'd put the thing, have you ever seen a 3kgt engine compartment?? I've dropped wrenches into my engine bay it took me almost an hour to get out. I seriously have 2 or 3 wrenches with a hole drilled in them to tie a string to for retrevial.

+1 I have almost a hole socket set in my 3k somewhere .

 

[RayPeters]

Quick update for those still following this, the factory ECU is gone, replaced with a AEM EMS. Not by choice, I was driving back from a clients shop and it died. I've been wanting to try the AEM for over a year now, so I decided this is the prime opportunity. I may be starting a new thread for this install, as there are some questions coming up I'm haveing trouble locating answers to. Once I get this thing tuned I'll be back in action and off to the dyno.

 

[nightspeed87]

Quick update for those still following this, the factory ECU is gone, replaced with a AEM EMS. Not by choice, I was driving back from a clients shop and it died. I've been wanting to try the AEM for over a year now, so I decided this is the prime opportunity. I may be starting a new thread for this install, as there are some questions coming up I'm haveing trouble locating answers to. Once I get this thing tuned I'll be back in action and off to the dyno.

Thats whatsup.

 

[tsiturbomm]

Could you get alot more videos of this thing running and speedo shots on highway pulls?

 

[Defiant]

I rev limit at 6.5 because I don't want a yard sale .

....across several neighbors' yards.

 

[RayPeters]

Could you get alot more videos of this thing running and speedo shots on highway pulls?

Ok, got that @#$%&^@* AEM mostly working last night. Man their manual SUCKS!! Gotta get my wideband talking to it and then I'll see what I can do for some shots.

So you're asking for what, a 40-100 highway pull??


I got the camera mount done as well so all is ready.

 

[nightspeed87]

Ok, got that @#$%&^@* AEM mostly working last night. Man their manual SUCKS!! Gotta get my wideband talking to it and then I'll see what I can do for some shots.

So you're asking for what, a 40-100 highway pull??


I got the camera mount done as well so all is ready.

40-100 sounds good. A vid of that pull in both cars would be even better.

 

[eclipsh]

It looks like this setup shoots the supercharged air straight into the intake.

Would it be better to run that air to the intercooler first? I understand that you are using methanol to cool air temps but as a D/D I think that'd end up being impractical.

I am picturing locating the supercharger underneath the intake manifold where the AC pump is and running the air down under the timing belt to a FMIC and then back up to the intake. The other option being one of those SC's that had a long shaft and mounting it above the air intake/tranny area.

Would it destroy the turbo if the SC were placed before it in sequence? Any gains/losses from this setup?

I too had thought about a SC inline for instant throttle response. Glad someone did it but damn is that a lot of ECU work!

 

[GVR4592]

If you need help with the AEM just post the questions in this thread and I'll help you out.

 

[Splitpi]

Would it destroy the turbo if the SC were placed before it in sequence? Any gains/losses from this setup?

I would think you run the risk of blowing the seals and/or having a surge hitting the compressor blades and causing it to counter spin or slow down.

 

[RedEclipse17]

I may have missed it, but what kind of turbo are you running exactly? sorry for getting off topic

 

[eclipsh]

He's using an 18g. It's listed early in the thread somewhere.

Yeah, I was sleepy when I posted that earlier... Just thought of something else for not having the SC first. The turbo will be sucking way more air than the SC at higher rpms so it would create a flow obstacle.

 

[Defiant]

So you're asking for what, a 40-100 highway pull??

No, that'll get your thread locked and infraction points for "street racing" here. If [when] you do it, don't post it, nor links to it, on this site.

 

[eclipsh]

Looking in eBay, that SC you have looks like it came off a GM 3800 series V-6. Is that correct? If so, they can be had for only $2-300...

 

[JFZERO ECLIPSE]

Wow thats really bada$$ been reading since the very beginning....Very impressive with this install.....I guarantee that over 1/2 of us could never even imagine this kinda install....

You were saying bout there being very little room to work....I seen a few areas you could be improved if need be
1. Relocate Battery
2. Remove CC get a 1.8 NT throttle cable
3. If your HC remove p/s and put a 1.8 mauel rack in or go with an unassisted p/s rack (I love the feel of it personally)
4. You already said your gonna get new pipes made...when you buddy is done with moving stuff from his shop...


But what I think is the craziest thing......You still retain the A/C.....thats gotta be the greatest....plus must be fun to work around sometimes....dealing with the entire belt situation....

I might not have caught it earlier but exactly which pulley is the belt connected too???you still got p/s, a/c, so you got me at a standstill wondering...

I'll continue to read and be in awe about your ride...

 

[andytalon]

If anyone new VW accually just came out with a new car that has the same concept. It uses a supercharger to compensate for the turbo lag then shuts itself off automatically. They call it the "Twincharger" its the new Golf GT. The 1.4 liter, four cylinder engine features a turbocharger and a supercharger to produce phenomenal maximum output figures of 168hp and 177lbs of torque. The torque curve should provide diesel-like cruising and acceleration, with the top-end fizz of a petrol engine. Top speed is claimed to be 137mph, with the benchmark 0-62mph said to take just 7.9 seconds. The major benefit of such a low capacity engine (other than cheaper road tax in certain countries) will be low fuel consumption and low emissions. This engine will eventually be available with the superb Direct Shift Gearbox too. Now this car is not yet in the US.

-Andy