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Discussion Starter #1 (Edited)
Ok I have read up a bit on the concept and see a few exige's have done it but what I dont know or have not found info on, is what do I need to know.

I already have a katana 2 and was planning on getting the rev400 but thought about saving money and going with a turbo in combination. I say saving money because that rev kit is 7k plus and have seen turbos for less. Plus the K2 does not have an inter cooler, guessing that would help fit a turbo on. Of course I still have the option of selling the k2 that I just dino'd. Runs great and has like 10k on it. Not sure if its worth 3k though...

Aside from flashing (may have to customize this a bit, I know who to talk to) and a new clutch what would I have to do so that the car cant take/fit this set up in an elise. Has anyone here done it? Would an inter cooler become a must at this point?

Just throwing it out there as using google didn't turn up much for me.
 

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Discussion Starter #2
I have no idea how this got in parts for sale, could someone move this to Elise or general lotus talk.
 

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Your current Katana is bolted to your intake manifold. It would require different mounts/manifold to merge the supercharger and turbocharger air flow. Final analysis, the cost of all the custom welding, fabrication, tuning might likely exceed the cost of the REV400.
 

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Without chargecooling a twincharger setup would probably be worse than your K2 alone. You're better off doing either a REV400, a smaller turbo with an IC, or a DIY supercharger + charge cooling.

The point of twincharging is to allow a fast spool off of the supercharger while still pushing huge volume through the midrange using a big, slower-spooling turbo.

There are two kinds of twincharging: series and parallel.

Series is the easier of the two (basically blow supercharger into the turbo inlet or vice versa), but requires a lot of charge cooling because while you're multiplying boost, you're also multiplying the inefficiencies of the turbo and supercharger (you're compressing and heating air once, then compressing and heating it again).

Parallel is complex: you need a diverter valve and some way to "choose" which boost source to use, which means for maximum efficiency you also need a magnetic clutch or some other way to disconnect the supercharger. That means lots of electronics, which will require a new ECU or a piggyback controller. I don't know if anyone's done a parallel setup on this car before and the control systems would easily blow your budget even before fabricating the necessary manifolds.

In short: your K2's output is limited by a lack of charge cooling, so you're probably not going to get anywhere without adding some.
 

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You want to compound charge a stock motor with an 11.5 compression ratio or upgrade to the Rev 400?

I understand you might not find much related to compound charging this car but if you make your searches more general you might find useful information on other vehicles. The one car that had this setup no longer does from what I’ve read, and I’m sure more than $7k (the cost to change to Rev400 plus or minus) was spent in doing so. I don’t think it will be an easy road if you go this way, especially if you have a small budget in mind.

Is there an end goal in mind or do you just want something different from everyone else?
 

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Do it!

I am truly confused by you. Last month you put regular fuel in your car because you thought you could save money. This showed a lack of understanding on how the car works, and now you are thinking about doing what is quite possibly the hardest / most complicated forced induction setup there is? This will be interesting! :panic:

Seriously you need to do MUCH more research on cars and how they work to understand what you are getting into... Things may sound easy until you realize what is required to make EVERYTHING in the system function properly...
 

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So going to throw this out there as Fred from BWR and I have gone around the block on this topic a few times. My goals are 350 hp and about 280 ft/lb of tq. So not crazy, however my cost point is much different than yours.

If you want to drive a car that has LOTS of power ALL the time, then sell your K2 kit and purchase a Rev400, and keep it below the 8k RPM limit until you do some engine modifications (Specifically new valve springs).

If you want a car with a little lag, and time and money tuning, and putting together EVERYTHING you will need to route the turbo kit (even though you can find used kits for about $2500 right now) then go for the turbo. The benefits of turbo vs. SC is something you can research and then decide from there. To do a two F.I. system is not suggested as Ronin was one of the few who did it...and personally I would do a K20 swap LONG before I went with a Bi-Forced setup...far more reliable and as much fun if not more enjoyable.

My 2 cents.
 

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I'd be very concerned about reliability as well with a compound charge setup. Frank's car was always in pieces because stuff kept breaking.
 

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Frank did the turbo/sc setup. I believe it took about $100,000 to get it all sorted and then he was still breaking parts because of so much torque/hp

You need to change transmissions, gigantic charge coolers (aka cut out your trunk) and thousands and thousands of dollars in tuning. I am not talking to get his hp numbers, I mean to run normally on the street

And I will be quite "Frank" with you. If you do not have a unbelievable amount of hours in research and knowledge of all the systems and how they work and how they work in connection with each other, Frank will not talk to you or help.

LotusSport.org ? View topic - The 211 Project
 

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rule #1 about twin charging... if you have to ask a forum about it, then you aren't properly prepared/educated...

:facepalm

the rev400 option however will be significantly cheaper... take significantly less time to complete... & be as significantly fast as you need

oh & Phil will probably have more patience with you to top it off
 

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Yeah +1 just get the 400 and have fun it is cheeper in the ling run. Franks car was compound charged and is now straight turbo. He has tremendous experience with the 2zz FI. Do not attempt this. Albiet turbos show cheap but need to be well sorted. Search Hass turbo for experience! Remember adding power is addictive and requires multiple other components to be upgraded. Please do you homework. Tommy


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Discussion Starter #13
Is there an end goal in mind or do you just want something different from everyone else?
Mostly I read about this and wanted to know more. This thread just gave me all the info I was looking for.

The Elise has spiked my interest in many areas, I'm learning much and enjoy it all. I understand what a pain it is to read a post where the OP didn't research it but I just had no luck in the matter. So thanks to all the contributed to this thread.

I don't know if I'm ready for a rev400 yet but it sure is tempting.

:clap::clap::clap:
 

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re: Twin-charging

Based on the OP's ask, I completely agree that a simple supercharger is best for him.

Twin or compound supercharging is very complex. It requires a lot of tuning and know-how.

1. You will need one big intercooler or 2 smaller ones, one after each charger.

2. The interaction between turbo and supercharger is hard to tune for. When the turbo is spooled up, it will actually push on the supercharger lobes, which will put power back into the crank! :)

3. If you look at a lot of power curves, at the end they look like the turbo curve, anyway. The obvious question then becomes why all the weight and complexity....

There are interesting examples of compound supercharging. It works better on diesels, since they can take much higher boost pressures while the power and fuel economy improves (not the case with spark ignition).

1. Old Detroit diesel trucks and city buses ran 2-cycle diesel with a supercharger for scavenging (the original source of 6-71 roots superchargers on all the dragsters) and a turbo for power and economy. It was sequential.

2. All new 18-wheelers run dual sequential turbos with intercoolers in between.

3. Tractor pulls to get very high boost as in 100 to 200 psi.

4. Old supra's had 2 turbos. Most people what swap them out for one big one.

5. New BMW's have 2 sequential turbos on the in-line 6's.

6. Ronin's car was twin charges.

7. Simon in England twin-charged a Lotus. The power curve looks just like a lotus on 35R (turbo), only, though. Simon had a lot of fun tuning it.

So you really do not want to do that, unless you have a lot of $$ and experience.

Anton
 

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+1

Do it!

I am truly confused by you. Last month you put regular fuel in your car because you thought you could save money. This showed a lack of understanding on how the car works, and now you are thinking about doing what is quite possibly the hardest / most complicated forced induction setup there is? This will be interesting! :panic:

Seriously you need to do MUCH more research on cars and how they work to understand what you are getting into... Things may sound easy until you realize what is required to make EVERYTHING in the system function properly...
If you want to save money this is not the car for you! Try a Prius!:D
 

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A nice reliable setup, that's known to work, and pulls like a freight train is:

REV400 with 70mm pulley
JCR Headed Ported to our spec
Stage 3 cams
10.5:1 motor
Headers

We've built a lot of these over the past year.

On 91 octane, they make 355whp +/- 10.

You can lay a straight edge on the torque curve from about 2500 to 8500.

I just finished up two more this past week. It's the most popular setup people are having us do because it's just SO FRIGG'N FAST and you don't have to mess with. It's all on the stock ECU and will walk through most emission testing...

-Phil
 

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^+1
 
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