Thinking that myself....intercool after the turbo.

 

Ok, so like said it's not exactly adding the boost of the two, but multiplying the pressure ratios. So here is a chart of said multiples. Looks like the turbo is only gonna have to make 5-6 psi to get me the desired 15-18 psi I'm looking for if the blower is geared to make 7-8psi. So just how much heat is the turbo going to make at 5-6 psi, that need so much cooling??

 

You won't be the first...its been done MANY times on mod motor mustangs with mixed results. There is an article online ( I think muscle mustangs) that did a dyno test with twin turbos and a blower. Correct, it did make alittle more power under the curve compounded, but they took the blower off and just ran the twins...and it made alot more power at alot less boost. Its fun in theory, but doesn't really work good in the real world.

 

I don't like the concept in general for various reasons. For instance, choke flow on the turbo compressor will come at the same hp level as if you run the turbo alone. So, peak hp capability of that turbo will be somewhat reduced due to the parasitic losses of the roots blower. The screwcharger won't become a restriction because the air will be much more dense. But I could go on for hours...

Anyway, you can get some pretty cool 45 degree reducing couplers. I have a 45 deg 2" to 3" transition coupler on my PWC connecting the turbo directly to the intercooler with no piping in between. I found a 3" to 4" 45 on the site.

 

looks cool

 

why not run the turbo into a front mount then into the blower? it would help keep iat' s down and give you more room for BOV and Meth. i dont know where you had yours positioned on the turbo setup bu maybe an intercooler with inlet and outlet on the same side would work

 

ive read that same article and from what ive heard hellion power systems has pretty good results as far as under the curve
http://www.youtube.com/watch?v=trpSMlo7pN8

this was taken from another video of theres..
"Hey Guys, This is Craig from Hellion. Please remember that the goal with the compound deal is more AVERAGE power, or power under the curve. Also remember that the kits can be run without a supercharger, it's up to the customer what they want to do. The kit has made 1,188 rwhp on our stock '03 Cobra"

 

Where did you find this graph?

 

I believe a guy on performancetrucks.net made it by multiplying pressure ratios.

 

The only reason to do it is just to say you have a supercharger and a turbo???

 

Nice keep us up to date on progress and some numbers

 

No, that's not the only reason... Geezz you guys have a 1 track minds and no imaginations. This truck is for the street with an occasional trip to the track. Yes, the coolness of it is key, but why I want to do it is cuz I want the low end boost of a PD blower and the top end pull of a turbo. I never said it hasn't been done, cuz I know it has, Hellion as a TT kit for superchaged Cobras, I found several Diesels that are using PD blowers to spool BIG turbos and have almost no lag and VW makes a gas car with like a 1.8l motor that has a PD blower and a turbo. I've been researching this for quite a while. I know I'm going to loose a little off of both, but it still should have more in the middle to make up for it.

One of the biggest things I don't like is when I go to the track, I have to brake boost the crap out of it on the line to leave with boost, which leads to inconsistend times and hard to bracket race. That has also lead to 2 broken output shafts on the 4l60 tranny which is why I swaping to the 4l80 also. I want to be able to just roll into it and still have good 60' times. The PD blower should give me that.

To give you an idea of the lag i have now, I did a little nonscientific test a few weeks ago just so I had a seat of the pants feel to compare to afterword. From just sitting still idling in gear, I stomp the gas and it takes about 3 seconds to reach 10psi of boost. I want to see how much difference it will be with the 4l80e, 3k stall, and PD blower. That's the surprise stop light effect I'm hoping to achieve

I said no one that I have seen has done it with and LS based motor in a combo like this. Ya you can do the same thing with spray and a bigger turbo, or hell, just spray... The point is out side the box thinking... Nothing ventured, nothing gained.

 

There seems to be a bit of misconception about this type of system around here..

First off, when sizing the turbo, you can consider the supercharged engine equivalent to a larger NA engine

Next the supercharger will be running through the same efficiency zone as it does without the turbo. With the R1900 running that level of boost you'll be right through the heart of the most efficient portion. But, the input power of the supercharger will increase because the mass airflow through the supercharger has increased (volume flow says same)

Twin screw or TVS... it doesnt matter what the internal geometry is, what does matter is the Isentropic efficiency.

I would reccomend putting an air to air intercooler before the blower, that will help with overall system efficiency

The VW engine is a 1.4L and has the boosting systems are in the reverse order.. supercharger is first.

 

It will come on quick with that blower on there!

I see where you are coming from on low end power with a less then optimal setup. Would be nice to run the tight converter if you want to use the truck like a truck still.

 

seems like the blower will take care of the low end so you would want to run a lot bigger turbo, like a 94mm or something. this would help pick up the blower on top when it starts to fall off and also help keep intake temps and back pressure in check on the low end. just my .02. its already gonna be moving so much more air than normal because of the blower the 76 just seems small.

 

nice im glad a few people are trying this id like to do one too one day. But any ways if you spray meth with Dual nozzles should be able to get IAT pretty lower.
My IAT were 190 with meth about 80

 

Well, been doing a little research and I think the t76 is gonna be a little too small, with the air flow and pressure ratio I'm thinking it's going to need to run to support the boost level I want to run with the blower/turbo setup. Looks like a T88 would be a better suited turbo from these maps. Also, I've been told Master Power is coming out with a T88 turbo that I think might just fit the bill. I think the blower will spool that turbo nicely though. I will have to see what they come out with. Here is the maps.



Here you can see here the T88 looks a little better



I am going to give the T76 a shot though, cuz no one really seem to know how this whole setup is going to really react to this. I have most everything ready for this setup, just waiting on a couple little parts to show up and having a small issue with the 4l80e I just install not locking up the TCC. Got a new TCC noid coming and if that fixes it, everything will be go for the blower.

Oh and for those of you guys who think It's going to have hi IAT's here is some pics of the intercooler under the blower. I really don't think a T88 is gonna make much heat at only a 1.4 PR

 

Also, here is a VERY good discussion/read from an engineering standpoint of how well a compound setup like this will work

http://www.eng-tips.com/viewthread.cfm?qid=174690

 

what exhaust housing you gonna run? should be able to get away with a lot bigger I would think.

 

The T76 I have now has a .96 a/r. I don't know what the new T88 will be available with. I know bigger would be better but I don't think I can get anything bigger for this turbo. I'm gona give this a shot first and see how it all works. I might pulley UP on the blower too, and let the turbo do more work and get it more in its efficiency range at a higher PR, we will have to see what it does.