I think I see what thermal dynamics are being ignored. and yes your right probably the loss that I would get from having to spin a small enough pulley to make the boost down low that I would need would probably more than eliminate any gains from this match. I imagine a larger centri this would be a combination possibly worth the attempt. With this high stall converter I should probably just slap on a t88 and call it a day. Although I am interested in compound turbo's. I know little of the setup I doubt they are worth it as I have never seen any big hitters running compound. Twins are another option since I already have a 60-1 garrett sitting here. Thanks for the input guys. Just thought it would be interesting to try to run both. The sound of leaving off a two step with a large turbo and a centrifugal makes me get excited.

 

But the fact you have chosen two blowers, with similar downsides makes the entire idea stupid.

And you mention compound turbocharging. Read up why this is used, before thinking about it, as its another dumb idea.

The only sensible 2 blower option, is one where each type of blower compliments the other. Not holds each other back.

You need one that will assist power in the lower rpm range. ie a PD type blower ( or small turbo )
And one that will then carry power through the upper rpm range. ie, centri or turbo

Anything else is just dumb

 

I was unaware a centri supercharger had a lag. That makes no sense to me. But that is the only type of forced induction I have yet to personally work with so I am not going to question it. Seems to me though as with any other supercharger if you match the pulley correct you can have your down low you need. On my car I run daily I have a pd and i had to machine the snout o the supercharger to clear the pulley. I have boost at 1000 rpm if i want. seems to me the centri would do the same. but that is just "seems" i have no way to back this up. the s trim v-1 is not that small. its good for 600-700 hp. So what I am getting is your saying a centri will basically need to "spool" like a turbo? and yea compound I am not really keen on.

 

Yes, a centrifugal supercharger has something like lag. It is not a positive displacement devise. Just look at it---it is a belt driven turbocharger compressor housing. It will not make max boost untill it gets spun up---high rpm.
The only time I would use a centrifugal supercharger with a turbocharger would be in a Duramax diesel. Put an F1 Procharger with a small pulley (2-3psi at idle??) blowing into a large turbocharger. No lag, but tons of power everywhere .

 

ok fair enough. guess that ends that idea. good thing i bought the whole kit for 400$ and already sold the fmu and boost reference timing retard module ha ha ha.

 

It doesnt have lag. Airflow from it is always present. As to whether that volume of air is sufficient to make boost, is another matter.

And you cant just gear it up to spin faster. You can only spin any supercharger so fast, before damage might occur.

Why would a centri do the same as a PD, when they are so completely different ?

A V1 is small.

 

do a compound turbo set up

 

I understand the air flow is there. now does a centri build boost in the housing as does a screw style supercharger or is it similar to a roots? to me the way it is designed it is similar to a PD. maybe I am mixing up my terminology. If so will someone please correct me?

 

PD + Turbo = Good Compound Boosting.

Edit: And I can imagine it being relatively dangerous all that boost hitting at once...o my. lol

 

Ya know...too much of a good thing isn't always bad...blondes and boost for example.

Who the F cares, do it, make it work, be the first.

 

It doesnt matter if it is capable of building boost as you put it ( compressing the air )

If there is no restriction after the blower, that air will de-compress again.

The restriction is the engine, and the blower needs to be shifting a lot more air than the engine can consume in order to make boost. With a small blower, it just aint gona happen until the blower really comes on song.

 

no, a centri is designed like a turbo... except its pulley spun, rather than exhaust spun.


Centrifugal charger


Turbo


see the similarities? I'm sure you know what a PD blower looks like, since you said you've worked with them. Most centrifugal blowers still don't have the low end grunt that a positive displacement blower has, mainly because they have to spin up to several thousand rpm to really get going. hell the little P1 will spin to 65,000 rpm.

 

yea i am aware of how they look but they both seem to work similar. i have all three next to each other and a roots moves air but does not build boost inside the housing. I believe screw type superchargers build boost in the housing. that is the statement I may have backwards. but the centri when taken apart is a gigantic fan blade. mine is straight blade which seems to me would not build the boost in the housing but rather move the air causing a low presure drop in front and high pressure in the housing. I am just going twin gt35r's as i already have a brand new one sitting here. I am giving the centri to my friend with a ls1 camaro and we are jut gonna boost his car too. why have both units on one car when you can have one unit on each

 

why not just run twin GT35rs turbos? They will spool fine on the 6.0. if you wanted stupid fast spool then you could look at using N2O to assist with spool. Alternatively you could look at a couple of quick spool valves like what Zombie used on his rear mount.

Just thinking of alternative ways to achive the same goal......

Chris.

 

quick spool valves? what are those? i have never heard of them.

 

here is a link to the product:

http://www.spracingonline.com/store/...ool_Valve/3659

and here is a link to Zombies building, using a similar vlave:

https://ls1tech.com/forums/forced-in...ke-graphs.html

If you google it there is some more info.

Chris.

 

damn! that is VERY interesting. It basiacally does the same thing a variable vane turbo does. I wonder if the longevity is similar. but I will for sure be doing a gt88 with this! thanks man!!!

 

the electirc clutch reminds me of Mad Max. great movie. lol

 

Or Chuck Norris' Supercharged Dodge (I think) SUV (?Ramcharger?) in Lone Wolf Mcquade