Supercharged/Turbocharged 240?

[Stereophile33]

Has anyone ever tried a supercharged and turbocharged 240 setup. I was thinking that a belt driven supercharger with a clutch on it that would let go around 3000-3500 rpm and then let the turbo come in since it will have then spun up. I am trying to figure out a way to get good low-end yet maintain that great mid-to upper RPM and efficiency of the turbo. I was wondering if a supercharger would help with the low end? Any thoughts out there? Let me know.
Peace,
Jonathan

[luke242ti]

Has anyone ever tried a supercharged and turbocharged 240 setup. I was thinking that a belt driven supercharger with a clutch on it that would let go around 3000-3500 rpm and then let the turbo come in since it will have then spun up. I am trying to figure out a way to get good low-end yet maintain that great mid-to upper RPM and efficiency of the turbo. I was wondering if a supercharger would help with the low end? Any thoughts out there? Let me know.
Peace,
Jonathan
How much low end are you looking for? How much power total are you looking for?
My bone stock 242Ti produces 155 ftlbs @ 2500rpm @ 6 pounds of boost. You can get a small turbo that spools earlier and produces more torque.

The supercharger would need to correctly sized to provide boost at low RPMs, but the problem with that is it could overspeed the supercharger at higher RPMs (without a clutch of course)

take care

[BLOWN240]

my charger gives tons of power right off idle. .

[scubthebub]

my charger gives tons of power right off idle. .
yea, but it is (by design) less efficient then a turbo. the super charger adds power, but also steals power to run it's self. a turbo, on the other hand, runs off of wasted exhaust gas and therefore is much more efficient then a supercharger at the same boost.

if you want to get really fancy use 2 turbo's. use a small one that will spool super quick and give you immediate power, then a huge turbo to give you power in the uppper range.

[Angus242164]

http://www.hilmersson-racing.com/start.asp?show=ea

This car uses a supercharger and large turbo combo with great success. Some Toyota engines actually used this concept from factory.

It can definitely work, but as others say, a small turbo and a large one may work better. The engine bay layout and available space, and cost also have a big impact on what would work best for your particular application.

[benboy]

Lancia did this in the '80's with some of their rally cars. Supercharger was used for low rpm duty. As rpm's went up the turbo came online, the supercharger freewheeled at this point minimizing the drag. Very complicated intake system to say the least.

[740Weapon]

i think to get better low end you should look into a 2.5l penta motor and choose a cam wisely. no replacement for displacement.

and if you make the engine more effiecient. i.e. ported head, exhaust mani, 3" exhaust you can get better off boost response. if you lower your rear end you also get better off boost response. i hear if you get megasquirt you can tune the engine to have less lag.

and now for this: $$$$$$$$$$$$$$$$$$$$$$$$$$$

[PWRPUFF]

Lancia did this in the '80's with some of their rally cars. Supercharger was used for low rpm duty. As rpm's went up the turbo came online, the supercharger freewheeled at this point minimizing the drag. Very complicated intake system to say the least.
Same idea I've had in mind. A pair of spring check valves to close off each side (to whichever is active) a and a pressure switch to disengage the s/c when the turbo starts making more boost than the s/c.

Keep the s/c small, and the turbo big. That could work.

-- Kane ... having it run off a MAP sensor based system would make it easier for exterior air intake and pressure relief too.

[Stereophile33]

I am just concerned that a twin turbo setup where one turbo helps spool a fatty will cause some serious heat problem....is there anyone out there that has done a TT on a B23 or 21?
Jonathan

[Forg]

With a bit of research you don't need multiple turbos or twincharging; just use the correct turbo size to start with. Unless you're a metal-worker with all the tools & access to parts, it's going to be cheaper to buy the best brand-spankers ball-bearing turbo, as to get almost the same performance by cobbling together a huffer & a hairdryer; not to mention tuning/timing/design of all the bypass valves etc (and such things are inefficiencies in your exhaust or intake-path anyway).

eg. New turbo cars like Lancer Evo's have got balls to spare off the line, and their turbos are quite happy to let their motors rev way beyond what's worthwhile with a substantially-standard red-block motor. Similarly, the current Legacy GT is quite a lot quicker than it's predecessor, despite being a bit heavier & having the same peak power, 'cos they've gone back to a single turbo & gotten rid of the "torque hole of death" that existed in the predecessor - and if Subaru can't get turbo phasing right, imagine what it's going to cost to get it right when you're not a multinational conglomerate?

[Benjam83]

I've thought of this myself and seen it discussed. But whenever I think some notion such as this up...I tink to myself....hmmmmm, if this were a great idea, an automaker would ahve already done it.

[mAydAy]

ILancia did this in the '80's with some of their rally cars. Supercharger was used for low rpm duty. As rpm's went up the turbo came online, the supercharger freewheeled at this point minimizing the drag. Very complicated intake system to say the least. I had looked into doing a twincharge setup. In looking around, I pulled up all of the Lancia schematics of the intake and charged air systems. After seeing all of the lines and the complications, plus all of the potential for losses through leaks of all the lines and stuff, it just wasn't worth it. Also, it'd be so expensive I'd rather just drop the money on a GT or a Turbonetics ball bearing turbo (Lets not get into the steal vs ceramic here ;)). Pretty much, you may as well go with a properly sized turbo and stay with it. Plus, you can't use off-idle power that easily, all you do is get wheel spin and once you've launched you can easily keep your RPM's up. My 15g spools so fast that I've hammered it at as fast as 50mph and as soon as it upshifted and nailed into boost the sh!t would break loose. Even in gear running with it as soon as you lean into it, it takes off (Sure, its still a small turbo, But a big one is coming soon to prove a bigger properly sized turbo can do the same.)

-Andy

[Bishop]

Nice concept idea, all done before already by a few car makers with alright results, but kind of outdated now, because you can get off the shelf turbos that have an awesome effective operating range, with super fast spool up, teamed with the right cam and intake/exhaust setup and it's very hard to beat in terms of power per dollar overall.

[Stereophile33]

Well this is all food for thought. My problem is that everyone is talking about single big turbo's....let take a look at what I want to do. I do not want a car that come on at 50 mph. I don't want a drag car....any guy can drive in a straight line. I am trying to build an ultimate volvo track machine. Some of the road courses have really tight turns and are 1st gear turns and u turns that slow you downn to 10 mph, I need hp right out of that turn not lapping and waiting for a turbo to spool up.

Also, many of you speak of want I want to be a really easy thing to do. If that is the case then why are people not doing it and having reliable cars. Most of the guys that I know here are turbobricks have lots of problems. Dougs car kept blowing head gaskets. That 242 that is for sale right now down in oakland is running blue smoke. I have yet to see someone build a 242 and I mean build it well for decent hp and then not have it blow up on them. I just am not interested in a car that will blow head gaskets left and right. I have been building sti's and rx3's and datsun 240's for the last few years...and those cars were so well build they could have been daily drivers...sometimes they were.

I just want an excellent track car that can also be streetable. To be honest money is not really the object in this product. But I don't want to reinvent the wheel. Some of the cars I have looked at have spent upwards of $30000 only to then change their mind because it didnt work out. I want to build an engine and I want to only build in once. I want to do it right...the first time.

If anyone knows of anyone that has built a "RELIABLE" turbo volvo that is track worthy and streetable please let me know. As their expertise would be invaluable.

As I have almost given up hope on a B21 of B23 and have thought about going with a T6 motor in the 242 and running pretty low boost. I like the torque and technology and reliability of the T6.

Any thoughts?

[benboy]

Yeah, I think Lancia liked to go to extremes in a very serious way. They also had a twin-turbo set up with that cool cylinder head with the intake valves on opposite sides of the combustion chamber. Similar to the BMW Apfelbeck M10 engine. Interesting engineering, but not for the shadetree tuner.

[mAydAy]

T6? Reliable? HAHAHHAHAHAHHA Thats funny. Even funnier is considering the twin charged system to be reliable.

You point at RX3's and STi's and 240z's. All of these cars have problems, don't tell me they don't because I've experienced them. The biggest difference with the built ones though is budget. How many people here could afford an STi? Not many. Because of this sometimes compromises are made with our cars to do the best we can do with a much smaller budget. Also, most people here DO drive their cars daily. Maybe thats why they do have more problems.

The thing is, a project car is gonna have problems. Doug blew headgaskets because he was spiking a lot and the headgasket just couldn't take it and probably were some other things wrong there. Sometimes, some problems are the compromise for not having an infinite budget.

Having a twin charge setup is going to have, well, probably about 4x the problems of a turbo car. Turbo cars are often slightly less reliable than N/A. Why? Because they're more complicated, they have more working parts. Twin charging a car you have MUCH more working parts than you have in the turbo setup. Now you have the problems of a turbo, and the problems of a blower, and the problem of making them work together, and fitting them under there. You're chopping off your nose in spite of your face here, you're just making it worse on yourself. I LOVE the twin charging idea, but you're looking at it for the wrong reasons if you value reliability.

See, you don't seem to be used to using too many newer turbos, and you seem to need some practice with driving. With the turbo car, you just have to lean into the throttle a touch earlier to start the spool for one thing. Most newer turbos you can roll into the throttle and will spool very quickly. Right now I've sort of shifted from striving for more power to striving for more traction for all of my torque. If you properly match a turbo to an engine, use a ball bearing turbo and set up everything properly, lag is not a problem. Probably, you've just experienced too much Supra syndrome with people who can't handle it. I know several people, one of whom you should be hearing about on the site before too long, who run regularly at the Nurburgring with their Turbobricks and can smoke everything around. A guy I know with an 850T whooped up on an e36M3 at VIR last year, because he knew how to drive his car better.

Before you go making it more complicated, try looking closer to home and improve the simpler things that are more likely the problem.

-Andy

[stylngle2003]

also, if youre worried about not having enough boost in the turns, you need to learn how to track a turbo car, you need to practice left foot braking more, because thats how the experienced race drivers keep their boost up in the turns. a properly sized turbo should come on very early in the rpm range, last throughout, and provide great response all around. also, the reason us 'murcans cant get huge power and reliability out of our bricks is because we sacrifice compression ratio and max boost capability for boost repsonse. the sswedes are running like 8.0 compression and less and insane boost levels, and they are making more power and seem to me to be more reliable.

big power supras and stuff are crazy unreliable...thats the name of the game...when you triple stock horsepower, you aren't going to keep stock reliability...thats just life. and also, before you go throwing mad-crazy power down in your own brick (i presume a 242), take it to the track and drive it in stock or current form...chances are you may need to work and hone your skills a bit until you get used to the power level you have. sure, you may not be able to run down vettes, sti's or evo's down the straight, espeically when you first start, but they cost likely at least 20x what your car cost you, so no big deal. my best friend has a stock RSX-S (200hp, 6 spd) and afetr his track session this past year, the first thing he said to me when he got done was "man, that car is soooo fast as it is...i dont think i need much more power", and its the truth...i've driven it. all it really needs is some better front brake pads, a rear sway bar, a strut brace, and sticky tires, and it would be incredible.

truth be told, on a road course, you want consistency, grip, awesome brakes, and great control...i suggest you start by getting the brakes, suspension/tires, and seating in check and overbuilt for track duty before you start building an engine, because chances are you may be plenty fast as is with a hot suspension, hot brakes, and stockish power. only experience will tell, so good luck, and let us know what you decide to do

[Stereophile33]

My apologies for my last thread and if anyone was frustrated with me.

I have run scca for the last 5 years and worked a lot with Paul and his national championship MR2.

That being said. The last time I was out on the track even though I was heel toeing it like mad I was having trouble getting the turbo to spool up. The car felt like it wanted a load on it to spool up the turbo. No granted I am fairly new to my 242. But for the last 3 years I was driving an aussy STI. This was a great car, I feel that I should be able to get something similar out of my 242 if done right.

I do realize that I(the driver) and the number one problem on the track, but I have the money and the time to build a 242 right. I was to do it while I can. Someone said earlier that the swedes are getting nice powerband with their 24* builds. Where can I get info on this. I guess you could say that I am not looking for some 320hp spike. I just want 240 hp wide powerband and consistent. Any thoughts?
Jonathan

[mAydAy]

Hey - Sorry to hop on you like that.

The thing is, the T3 on the 242 is an old, out of date turbo, being fed by a restrictive motor with restrictive intake tract (if its stock), sub-par fuel injection, and low compression motor pushing it all. I'd say your best choice is going to be go with a medium to high compression ratio for the low end grunt (I'd say around high 8's low 9's) and quick spooling, head work for ultimate flow, later style intake manifold or even a plenum and equal length runners if you're capable of fabricating one, better intercooler, some sort of programmable fuel injection and ignition system, and a nice, newer turbo. The Mitsu turbos spool pretty quickly. Or something higher tech, such as a ball bearing turbo from Turbonetics or a Garrett GT series. See, you've got a car thats using 20 year old technology, so your best thing is to try to update it and optimize it since it wasn't all out performance in the first place. With this setup I've said, you could get a solid 300hp curve. Along with the boosting of the turbo, Its also important to get a good transmission behind it, LSD, and properly matched rear end gear ratio.

-Andy

[Forg]

No granted I am fairly new to my 242. But for the last 3 years I was driving an aussy STI. This was a great car, I feel that I should be able to get something similar out of my 242 if done right.
Even the very latest STi's here are laggy ... you should be able to do better with the 242 (in terms of non-lagginess), having 150kg+ (360lbs+??) less weight and 300cc's more cubic capacity. OK, the Subaruba engine is going to be more efficient without LOTS of money thrown at the Volvo, but a 15% capacity increase has to count for something.
[The above comments are made assuming you're not looking for 400hp or something, if so then very expensive options may be worth a look - but I still think engine limitations will affect you mroe than turbo ones]

Find your nearest MrBishi dealer & drive an Evo8 ... there's a lack of lag for you. :)