Discussing CAPA Blower for twin-cam alpha motor again...

[Jiggy Verna]

http://www.capa.com.au/kits_hyundai.htm

I know this has been discussed before and that Bretton and a few others have dealt with this system first-hand. I have found myself back in this position where I need to know where my engine is headed next. These are a few of my questions. Feel free to answer as few or as many as you like.

1. Water to air cooling is an option but with only 7 psi is it necessary? I would not be boosting more than this.
2. Has anyone heard nightmares about this system? I know Bretton has but I was wondering about whether or not the cars were tuned properly before they went caput.
3. Would it be easier to just custom make a better supercharger that could be tuned and cooled more easily?

Please do not reply if you are going to say that I should Beta swap or go turbo. I am very familiar with these arguments.

[skierd]

Water-air intercooling is not available, however water injection is. Water injection simply sprays a fine mist of water into your intake tract to cool down the intact charge. Charge temp cooling IS necessary, even at low boost levels. Air when compressed gets pretty hot, and to prevent detonation the intake charge needs to be cooled.

The only issue's i've heard is an extreme sensitivity to octane. From what i've heard it tends to ping at throttle tip in and transition loads, due to inadequate fuel management. But thats ok, you cant use any of that stuff anyways (RRFPR and a chipped ecm) because it wont work on USDM cars.

In response to 3, yes. Its called an exhuast driven supercharger, or "turbocharger".

[Jiggy Verna]

So, with good engine management (I would have the unit tuned by a VERY reputable shop nearby) I should have good results with this supercharger? If the problems people are running into are related to fuel management then I can cure that with a little extra dough. If I am wrong please correct me.

[beppomarx]

americas best voided warranty- :lol::lol::lol::lol: nice one!!!

anyway i have no experience with this particular kit but like dadve said, the ECU chip or management unit will not work with our cars. you would have to buy the kit, install teh hardware, and find another means of engine management; be it an SMT 5 or 6, or just an S-AFC fuel controller, or go all out to a standalone ECU. the kit itself is nothing more than an eaton m30 or m45 blower (i cant remember offhand) bolted to a custom intake manifold that suits our alpha head. from looking at capas pictures it doesnt look like there is a 5th injector but either it is hidden well or you get 4 new injectors to suit it.

if you are willing to work with the kit then go ahead and do it. but with only 50% more labor you could choose a blower of your choice, have a shop fab an intake manifold to suit it (even fit a water/air intercooler which is NOT an option with CAPA and a huge advantage for forced induction in general), add 4 new injectors and youve just gotten as far as the 'kit' will get you because either way its not bolt-on and will require new fuel management and dyno time.basically with the kit youre paying for the custom intake manifold mounted to the blower and almost everything else will be your responsibility. which is why you dont see many if any at all in the US.

[skierd]

Originally posted by Jiggy Verna
[body]
So, with good engine management (I would have the unit tuned by a VERY reputable shop nearby) I should have good results with this supercharger? If the problems people are running into are related to fuel management then I can cure that with a little extra dough. If I am wrong please correct me.
[/body]

It all depends on what you consider "good results". This will not get you in the 13's, I'd say mid to high 14's at the most with the rest of the car built up around it. You are basically limited to 6-8psi at the most, due to insane intake temps, and only higher if you choose to run water injection all the time or force fit an intercooler. However, too much beyond the 10psi range and the M45 that comes with the CAPA kit is running out of steam, meaning low efficiency, lots of drive losses, and LOTS of wear on the blower.

The only real issue with water injection is the fact that you can easily run out of water if you dont keep a semi constant eye on it. If you're motor's tuned with water injection, and you run outta water, expect to buy a new engine (detonation). If you're fine with that setup, then go for it. I'd talk to CAPA and see if you can just order the supercharger itself, with none of the engine management.

Basically, will the CAPA kit get you where you want to go with the car? In the end you'll probably peak out at 140-160whp tops, which although is nothing to sneeze at, it wont be as flexible or cheap as some other options that are out there to someone with a little skill.

[Jiggy Verna]

Well, I see the points that you both are making. I am not saying that I will definitely get the kit but I'm trying to decide now where I would like the engine to go in the future.

Skierd, you stated that 14s is all that he would expect from this setup. Right now Scrud is only running 14s and he is already on stand-alone and has a really nice setup. He'll go faster as time goes on of course but only with lower compression and more boost.

What other upgrades could you make while running this kit besides more boost (since you stated more boost would not be practical)? Would a bigger intake cam hurt or help performance. I've heard that anything under 270 is okay for FI. Also, would I be able to bump up the compression safely with this setup?

Beppo, where would I start looking to maybe get a custom setup done? Please go into more detail about what setup would be good for this motor and maybe a parts list you would recommend.

Thanks.

[beppomarx]

well first off, if by bigger you mean more duration on the cam then you really dont want anything to do with that when boosting. you only want a few degrees of overlap from when your exhaust valve is closing and your intake valve starts to open, for having large overlap (more than 10 degrees or so) the boosted intake charge will start escaping out the exhaust valve. to change the cams you would need to graph the cams profiles and measure how much area is occupied under the duration of overlap. then compare that to the amount of boost youre making and therefore how much ambient air would be entering the combustion chamber given the time interval at any given RPM. once the pressure in any given time will flow more than the combustion chamber can hold, there will be blowby and you will waste fuel and have bad emissions, and lose power. in other words, stick to the stock cams or if you want cams, get a set created for yourself not just the intake one. then you will have the cam timing set to where it really should be and not have overlap, but the manufacturer may increase lift slightly.

an upgrade to THAT kit would really not be worthwhile because theres only 2 feasable things to do.

1. add a intercooler. be it water or air but regardless you still would need to redirect teh plumbing of the intake manifold, which woudl defeat the whole purpose of having teh kit because like i said, its nothing more than over-the-counter parts with a custom intake manifold.

2. go to a bigger blower to increase boost. however doing this would induce the NEED (not luxury) of having an intercooler. you would also need a new manifold to mount a larger blower, and also fit an intercooler of some sort.

as far as bumping UP compression, no. if anything you would benefit more from going to 9:1 compression, to set the timing at a more ideal level and not detonate and also support higher boost. you should read up some on how a piston carries load during combustion. you will notice that with a very high compression almost all the load of the piston is a sudden WHACK of acceleration, and has almost no force driving it near BDC because the small combustion chamber's volume wont expand enough to still be making force. with a lower compression, you have more area to fit air and fuel molecules and there will be more power to push downward, plus the chamber is pressurized beforehand. now youve got more pushing power in general and more gaseous area. gas can expand and take the force and sort of cushion it before it hits the piston so there is actually less maximum load on the piston at TDC and teh power is more evenly spread to the piston and crank on its way down to BDC. this is how forced induction makes more power for you my man!!!!

edit

sorry i canot reccomend a place to do that. me myself when i do this (taking teh same route youre thinking of only next spring hopefully) i will choose a larger blower once i research them more, possibly the M90 and draw up schematics for an intake manifold. match it to the ports on the head and the blower and also integrate a water/air intercooler. then take the design to a machine shop and have them CNC it out of billet aluminum. basically my dream is to design the system from the ground up myself which i know is not easy and will be a lot of work and math and money, but something i want to accomplish myself. thats why i cant recommend anyone, because my recommendation is myself X). i will take it to a dyno only to get it tuned afterwards but the rest of teh setup is going to come from hundreds or even thousands of hours of research and development by one person :

but if i do get it running and set right ill be sure to drop you a line and ill make you up a kit ok 8D

[Edited by beppomarx on Oct 28, 2003 2:33 PM]

[skierd]

Beppo- in a word... I disagree completely.

Remember, pressure is not airflow, and the amount of airflow at a given pressure level will vary according to the volumetric efficiency of the motor. Therefore, its perfectly reasonable to have a 160hp or 200hp motor at the same s/c speed, all depending on whats around it.

To truly take advantage of the extra air coming off of the supercharger, you really need to port and polish the head, as well as run a 4-1 large tube header and end the system in a 2.5" exhuast from the header collector back. You should also clean up CAPA's IM if it needs it, run a larger throttle body (58mm or higher imo since you're essentially flowing for a motor thats 45 cu in larger than stock, i.e. a 2.0L). A free flowing intake, be it a CAI or a WAI are good ideas too, as is anything else that adds to the VE of the motor. RPW can even set you up with a set of cams for a boosted car.

One thing you will notice is that the supercharger will make less and less boost as you add these mods. Do not be alarmed as its still flowing the same amount of air, however the motor is better able to swallow this volume of air therefore boost drops (since boost is really an indication of how much "extra" air is being forced into the cylinders). This means lower charge temps and less parasitic drag losses at the same pulley speed, meaning even more power. Basically, in a supercharger you keep maximum airflow constant as you increase VE, but the amount of work done to make that airflow goes down.

This applies to turbochargers as well, but due to the turbo being controlled off of the exhuast gas, you keep a constant maximum boost level in the system, however as VE increases you effectively shift the motor's demand curves right on the compressor maps (i.e. flowing more air at the same psi).

Cliff notes: Impove the VE of the motor once its boosted to make more power than normally possible.

Hope this explains things a little...

[beppomarx]

dave- that was three words :

i understand what you are trying to say and did beforehand and admit i left out huge piles of information that you tied up in style. but everything i said about cams and piston kinematics is entirely true. again i could not comment on capas IM or TB, it may very well come with a 72mm TB for all i know. but i did disregard the head ports, i just commented on the 2 errors in planning that he was asking about.

and in #2 i realize i used the term 'boost' loosely. i did not mean the actual PSI i mean the number of air molecules that are accelerated into the manifold. and the ports/valves can only be opened up so far, which is why an intercooler would be almost imminenet.

i also know taht he is running a 4-1 pacemaker header with 38mm primaries, 2.25" collecter and 2.5" exhaust from there back, because he is running oen of my 5 sets of extractors that i had made, around march.

nice cliff notes :bandit: although HIGHLY abridged to the point where it is more like a general rule of thumb. good sticky too :

[Jiggy Verna]

Thanks for the sticky, skierd.

I appreciate the two of you correcting my errors and further informing me on the subject. I e-mailed CAPA and am going to ask one of their reps to post on the topic as well. They have some decent claims on the site about the unit and maybe they would like to post a bit about it.

Beppo, I appreciate your offer to make me a unit styled after the one that you will be building in the future. I may take you up on that.