Twincharger v2.0 teaser...Photos inside

[this_tsi_8urV8]

Hey Ray, how did you come to the conclusion that 7.5 is what you need?

 

[RayPeters]

Hey Ray, how did you come to the conclusion that 7.5 is what you need?

I didn't do anything super scientific. I asked some local engine builders, and did some cylinder pressure calcs for the longer stroke, and decided that 7.5 was as high as I wanted to go. The 7.8:1 engine I destroyed from detonation worked ok, but I can't get any of those either. So as long as I have to make pistons, I thought I'd get something plenty safe, more boost pressure is easy for me to achieve. Remember I have no off boost performance issues as I have boost as soon as I open the throttle.

 

[this_tsi_8urV8]

Yes I was thinking about the 7.8, but forgot you had used those already. I guess 7.5 should be a good bet. Now like you stated earlier to find them will be the hard part. GL!

 

[LaN-]

Update: Made it to the dyno, 468 ft lbs and 452 HP. I'll have to scan the sheet at home if I can get my POS Epson scanner to work. 22psi and ~600cc Methanol. I think there is more to be had, but I need to build the better bottom end. Any suggestions for a 7.5:1 stroker piston / rod combo? I'm having problems locating a supplier for the pistons. No one wants to go that low on compression.

Lan - I almost have a dual TB setup done, one for the SC and one for the Turbo. The gas pedal controls the max openning amount and the pressure from each device drives the throttle plate open against the stop. Once the turbo spools, a pressure switch de-clutches the SC and the TB for the SC closes completely. Food for thought.

DAMN! Nice numbers.

I like the dual TB idea. I ordered some pressure switches that will control the bypass valve.

I'm still waiting on parts so i'm still in the same position as before LoL.

Hopefully everything should be here within 2 weeks

(I ordered pretty much everything you could possibly imagine ........all the supporting mods for a Green and my entire suspension.)

 

[LaN-]

Hey ray, what tensioner pulley are you using for the S/C belt? I have a few ideas of how i'm going to mount mine but i was just wondering.



After i looked at it in more detail.......you made 450 Awhp on the 18g? Thats amazing

 

[RayPeters]

The goal was 400 hp and 500 ft lbs, I'm still tweaking. I am using a modded factory pulley. I'm using the factory AC bracket with a new center section, a little different than the pics I posted a while back. I machined the groves out of the pulley so I can run it on the back of the belt.

Just a thought, but have you verified you are going to be turning the SC the right direction? It may sound silly but some are designed to rotate the wrong direction for our cars.

 

[LaN-]

Yea i made sure everything will be rotating in the right direction. There is a little arrow on the S/C

 

[dsm-onster]

This is all very interesting. And I've been toying w/ a set up very similar to this for quite some time. It seams that this would in fact be cheaper than a good stroker kit! And a 2.0L w/ a supercharger should definately displace more air than a 2.4L w/out. Nevermind the fact that a 2.0 is more square and can rev higher than a stroker w/out issue.

I plan on running the same supercharger being fed by my 60-1. And I will not be bypassing the supercharger up top. I want to wind out my turbo by 6000 rpms instead of 8500+ rpms. this setup would allow me to monkey w/ some larger tubine housings and still maintain 'streetability'. I have no problem w/ lag. But if I want to run a .82 a/r housing I'm going to need alot of road to tun her . This seams to be the way to go. . .

Particularly when feeding the turbo into the supercharger: why run the bypass valve for idle and light throttle issues? What issues arise? It's not that I don't trust that it needs to be done. Does the engine want to choke? Or does it boost irratically? Or is there some other issues?

 

[RayPeters]

The real key is the location of the throttle plate in relation to everything else.

Starting at the air filter here's the path.

Air filter -> turbo -> 1st Intercooler -> Supercharger -> 2nd intercooler -> bypass valve to atmosphere -> MAF sensor -> Throttle body -> Engine.

So the supercharger operates at 1.6 times the displacement of the engine, this gives us excess air under all conditions. The ISC cannot manage the idle speed with pressure at the TB (valve is pushed open by the pressure) so that excess air must be vented off so there is no pressure at the TB. The bypass valve is a heavily modified 1G BOV. I'm not going ito the specifics here, but it is setup to open under vacuum conditions and close as the pressure differential across the TB becomes zero. Also there is an air heating problem without bypass, the supercharger takes a lot of power and heats the air dramatically. Highway cruise conditions are the worst for the heating issues, high rpm and very low airflow demands.

So this issues from NOT using a bypass:

CAR WILL NOT IDLE on factory TB or mustang for that matter
High intake charge temps
increased belt wear
increased engine loading
intake piping can see pressure spikes of 30psi plus, that is very rough on enerything from the supercharger itself to the piping.

Hope this helps,

 

[dsm-onster]

This helps tremendously! Thank you. I can't wait to dive in. . .

 

[Mikael SS]

Putting the throttle body in front of the supercharger is an easier way to solve some of those problems.

 

[dsm-onster]

Ray,

I'm looking back at your post:
http://www.dsmtuners.com/forums/showpost.php?p=151158940&postcount=175

You managed a meager 468 ft lbs and 452 HP at 22 psi. Was this at the turbo or was this in the intake manifold? I'm trying to 'spreadsheet' this and my calculations are not jiving. . .

 

[RayH]

It's good to see new stuff being tried on our cars. For reference, here's the twin charger setup used on the Lancia Delta S4. It should be possible to build a lightly sprung one way bypass valve at the supercharger without going with electronics. It would open when the intake vacuum of the turbo exceeds the output of the supercharger and operate similar to when a weakly sprung wastegate is blown open.

For efficient air to water intercooling checkout Laminova intercooler cores.

 

[eclipsh]

That above map combined with an RPM switch for the magnetic clutch could be a very easy way to set this all up. Turn it on at 2k rpms and off at 6500 or so. It could also be wired up so that if the IPS switch is triggered (zero throttle) the clutch is disabled. You could also wire in a kill switch to disable the s/c when you're cruising on the highway and only turn it on when you want the added boost. I don't know what that'd do to fuel systems though.

 

[LaN-]

Please no one take offense to this, but almost all of this has been addressed earlier in the thread. (i understand if you didnt read it ### its a lot )

ray made those numbers on a 18g turbo. Where he got the PSI rating i am unaware so he will address this.

As for the Lancia Delta S4, thats the same image in the VW twincharger i was speaking about earlier also.

Again don't take offense to me bitching, i just want to see this thread keep moving in 1 direction.

To make things easier and if Ray has some spare time maybe we can do a recap of everything so far. Any thoughts Ray?

 

[eclipsh]

Lan - I know the clutch issue has been talked about but I can't recall specifics on on/off details. Are you referring to my post as well or the ones above?

Clutching the S/C in the way I'm thinking should work just fine. For that matter, I think the TPS puts out a varying voltage based on position (or clicks, I'll have to double check). Either way it could be set up to turn of the S/C at a given throttle position/rpm combo, say below 20% throttle and/or under 2k rpms.

 

[LaN-]

Lan - I know the clutch issue has been talked about but I can't recall specifics on on/off details. Are you referring to my post as well or the ones above?

Clutching the S/C in the way I'm thinking should work just fine. For that matter, I think the TPS puts out a varying voltage based on position (or clicks, I'll have to double check). Either way it could be set up to turn of the S/C at a given throttle position/rpm combo, say below 20% throttle and/or under 2k rpms.

I'm just talking about the above posts. I just don't want to see a bunch of repeat questions.




I will have the clutch and bypass valve be operating on pressure switches. If the car is under vacuum the supercharger is off and all the air goes directly to the turbo. When you reach 0 psi the valve closes and the supercharger comes active. It will then wait until you reach 10 psi (not sure if this is the correct number right now, i'm just using it as an example.) and switch back to the normal setup. (S/C off bypass open)

 

[dsm-onster]

well that leaves one poster because my question has not been answered in either thread as well. Oh well. . .

I ask this question because 22 psi -no matter how you look at it- can not yield such high hp numbers on a 2.0L (assuming the Ideal Gas Law has some merit here ). If you add the supercharger you're raising displacement, I know; but by raising the pressure of the aircharge even further. So needless to say, I suspect that 22 psi is befor the supercharger.

I'm attempting to formulate some "predictors" so that I do not destroy my engine (or an one elses) because of not understanding what probably will happen. If I do X, will Y or Z occur?

Thre is serious potential with this here. BUT, what is the extent of the potential. And what variables stand out as more important to reaching a goal.

As my math goes. It seams that intercooler efficiency has greatest effect after the turbo. Not that there isn't significant gain intercooling after the supercharger. But if you have a choice between a 75% efficient intercooler and a 80% efficient intercooler, placing the 5% better intercooler after the turbo and the remaining after the supercharger will yield a large plus over the other way around. However, raising the boost of the supercharger yields 15+ hp per psi instead of raising the boost of the turbo which yields a little more than only half that per psi. Other details are needed to verify this and establish a model, so I ask.

I'm seeing here in my scribble that you're supercharger if running w/out the turbo would yield you 14 or so psi where there is 100% intercooler efficiency (very high, you say you're running meth injection) after the supercharger. This calculation comes from the assumption that you have an 80% efficient frontmount (also high) running after the turbo and an 95% VE at the engine (good cams, good intake mani.)

I'm attemptign to forcast results using the supercharger boost because that can be measured for any setup (run w/ the wastegate on your turbo open and see where your boost is w/ jsut the supercharger). This seams a likely path to begin because everones vacuum is different as everyones set up is different. So I plan on forecasting what should happen by knowing the boost the blower puts out at atmospheric pressures. The knowing turbo intercooler efficiency and supercharger intercooler efficiency and turbo boost pressure before the supercharger, I can get the %VE of the supercharger and engine combined and then finally the hp output at the crank.

Earlier there was an assumption given that the supercharger will compress the air at the same ratio. I don't see how you can assume that the supercharger will compress the boosted air at the same ratio for every engine. As the supercharger has to overcome different vacuum levels depending on rpms, cam profiles, intake mani flow, volume displacement, etc.

 

[LaN-]

My guess is that he had his boost gauge hooked up to his intake mani like everyone else would.

I agree that 22 psi cannot yield those numbers,

I believe his power is created by the increased airflow the supercharger provides.

Later today i would imagine he will clear up the gray area's. Everything i've stated are just my best guess.

 

[RayPeters]

My guess is that he had his boost gauge hooked up to his intake mani like everyone else would.

I agree that 22 psi cannot yield those numbers,

I believe his power is created by the increased airflow the supercharger provides.

Later today i would imagine he will clear up the gray area's. Everything i've stated are just my best guess.

Gotta get some sleep, but really quick, 22psi off the turbo, 1.6 ratio through the supercharger should yeild you a approx 3 to 1 pressure ratio at the intake valve. That is more than enough for 450 HP. Because the ratio through the SC is fixed, I don't concern myself with the exact pressure, I can't control it at that point anyway. It is controlable with the turbo outlet pressure. There is only 2 connections to the manifold directly, the brake booster, and the bypass control. Hopefully that clears that up, I need to look into a 6 row drive belt as I tink I am loosing a bit from my calcs. 3 to 1 pr should put me well over 500 but as yet no luck. As for the recap, I'd rather work on my car than retype this stuff, reading isn't too hard.

Now for the meaty questions: The SC output pressure is 1.6 times its input pressure. Only work with absolute pressures or this math stuff doesn't work. A 2.0 to 1 ratio is like putting a block of C4 in the engine compartment, you will break something. Have you loooked at the eaton flow maps? 14 psi out of a roots blower is like pissing up a rope. The outlet air temp will be close to +200 deg over inlet temps. Be happy to have 10 psi and get the rest from the multiplication. The SC is simply a positive displacement compressor. It will compress air and pump it anywhere you pipe it, on engine is the same as the next assuming it is capable of handling the flow.

My guess is my losses are due to the 2G head, the smaller ports hurt the top end for sure.

Ok sleep time I'm not flowing well. Tomorrow ask away.

Ray

 

[dsm-onster]

Thanx Ray for answering these questions. It all makes sense now.

14 psi out of a roots blower is like pissing up a rope. The outlet air temp will be close to +200 deg over inlet temps. Be happy to have 10 psi and get the rest from the multiplication. The SC is simply a positive displacement compressor. It will compress air and pump it anywhere you pipe it, on engine is the same as the next assuming it is capable of handling the flow.

This makes sense. There is no way I'd be comfortable pushing over 10 psi at the supercharger. Besides my turbo likes high boost pressures anyway. It would be fruitless to have a 60-1 w/ an E cover and only be able to raise the boost to 15 psi because my supercharger/engine flows too much . Wow, a 2.0L flowing TOO much. . .

My guess is my losses are due to the 2G head, the smaller ports hurt the top end for sure.

I guarantee it. As has been seen, the 1G intake manifold out flows all the SMIMs until around 6000-6500 rpms. Since you're not really revving over this anyway then the old 1G head and intake mani swap is the next step here for sure! Good thing I already have one .

I'm on Mcmaster-Carr's website looking for solenoid valves that might double as a bypass valve. All one would need to do is purchase a Hobbs switch from their local Napa and adjust it down to .5-1 psi (i've done this before accidentally w/ my homebrew water injection kit). And you have a reliable electronic release. . .

 

[dsm-onster]

On the subject of the bypass valve. Remember that a stock 1G (perhaps 2G too) is a true bypass valve. It is open during vacuum conditions. The "dodge garage mod" did two things for the dodge guys. It allowed to valve to seal better at very high boost but also caused it to shut completely during idle and vacuum conditions, which most of us want for a blow-off valve.

The 1G valve can't handle 35 psi across its inlet and outlet. But, if you recirculate it -like it was originally intended- around the supercharger, then the only pressure differential the valve sees across its inlet and outlet is the pressure differential of the supercharger... which is approximately 10 psi (1.6PR) in this situation. Any unmodded 1G valve can handle this (2G as well). The unmodded 1G valve also is known to be a very quick acting unit, so it should respond rapid enough for this application. Now if the 2G valve acts like the 1G, except for the weaker spring, then we all have a new found use for the piles of 2G bypass valves that are chucked for little to nothing

Recirculating would also do away with that annoying noise on your long trips . But blowing off in the atmospere at 35+ psi must sound insane!

The unknowns are:

-How much does the valve flow when open and is this enough for the supercharger?
-Does the valve want to remain open until around 0 psi?
-Does the supercharger need it to vent until 0 psi? or is there a good compromise already dialed in these bypass valves?

Since most of us already have blow-off valves/bypass valves that can handle up to 24 psi, place your current valve after the turbo. Then, place an UN-MODDED 1G (or possibly 2G) valve after the supercharger (recirculating of course). 2G would be a simpler install as it must not have a special flange, correct?

EDIT: I think that this would be a guarantee to work because, if any force (psi) begins to build up against the valve at the inlet when the engine is in vacuum (even light vacuum), the tendancy will be to push it open further to release said pressure. And, I feel that the 2G valve would work best as it does in fact have a weaker spring. Go figure. That weaker spring comes in handy .

 

[eclipsh]

Where exactly are you having the 1gBOV recirculate to in this scheme?

 

[dsm-onster]

The first is RayPeters setup. The second is mine. Mine is just the typical orientation of a supercharger bypass valve found stock on engines which incorporate a stock supercharger (i.e. T-bird Super Coup, Grand Prix GTP, Regal GT 3800, etc.)

 

[eclipsh]

I'm a little confused as to how that bypass will do anything routed the way it is. Shouldn't it be going back into the line before the supercharger, and possibly the turbo, not after?