I CRX I

so i picked up a factory mazda CX-7 turbo (borg warner k0422) from a friend of mine and was wondering if this turbo would be good for 240 or so WHP on a stock d16z6 or does it look like it might be a restriction? the cx-7's are 2.3 liter motors so i dont think the 1.6 would get backd up but i wanted to ask for opinions. here's an ebay sale add for the same turbo...

http://cgi.ebay.com/ebaymotors/K04-t...#ht_1433wt_734

edit: here are a few more pics

I CRX I

would an aluminium flange adapter work between the turbo and manifold?

I CRX I

for comparison, here it is bolted to a z6 head, also, would it be wise to use the exernal waste gate or just stick with the internal?

integraturbo96

k-04 are use in audi to and I think its more 240bhp than whp that it can push

rat city rex

No alum, will not work for an adapter plate between your mani and turbo. it will melt.

I CRX I

thats what i figured, i saw an adapter plate on ebay that looked aluminium and figured that couldnt hold up very long on an exhaust manifold. anybody else know what i could expect from this little thing? is 240whp asking to much?

I CRX I

any info or suggestions would be appreciated.

Schister66

I dont see why that turbo wouldnt work for your power goals. It is bigger than a stupid 14b and people have made over 300whp on those outdated paperweights. One thing i noticed, in the picture showing the turbine (#4 in the first post), it looks like there is oil coating the turbine and exhaust housing. If so, you may have a crap unit on your hands; however, it could just be the lighting. Just something to be wary of...

I CRX I

thanks for the response. does this unit seem bigger then a 14b? ive heard quite a few people tell me about those and how they've seen some good numbers out of them. the exhaust turbine and housing seem to have a sticky coating like substance on them that appears to have come from the factory as its very smooth and evenly distributed. hopefully its not a blown turbo as these units shouldn't be older then 2007 but who knows.

mkriebs

Its a K04, in fact, its a SMALL K04. The Cobalt SS turbo uses a K04, and we run them well up to 350whp on the stock turbo, but thats also the biggest K04 available. Plus, you have to look at the LNF (GM turbo 2.0, Direct injected), its a very potent motor, and VERY efficient, whereas the D series I am sure is lacking in efficiency.

this turbo on the CX7 maxes out about 28lb/min, which on an efficient motor like a direct injected motor (like the GM LNF or the CX7's motor), can push about 9.8whp per lb/min. I see the D series being able to push about 9whp per lb/min, thus getting close to your goal, but also the turbo will be maxxed out. You would be running high boost, which will lower the efficiency of the motor.

You would be wise to spend the proper money on something a hair bigger, with a normal flange on it too. The money you spend on an adapter would be better spent on a bigger turbo.

I CRX I

would you happen to know the wheel sizes for these turbos as i cant find them anywhere. ive researched but cant seem to find much about them. i did see one article where it was stated the limits for this turbo is close to 22lbs which im assuming is measured at the turbo but im guessing i could reach my goals with just 10-12 lbs possibly?

mkriebs

I can't remember the wheel size off the top of my head, but i think that its about 38mm, but I could be WAY off, been a while since I have seen the specs. Thats also on the bigger GM spec K04.

As for the limits of the turbo, its all about efficiency. No, you will not reach your goal at 10-12 lbs. Not gonna happen out of this turbo. I was rating the FLOW of the turbo, not the capability of boost. Boost is dependent on numerous different things, a few being how free flowing your head is, how large your charge piping is, and how good of intercooler you run. The less restriction, and the more volume you gain (to an extent), the less boost you have to run to max out the turbo, because more air can flow through there with less pressure. Think, drinking pop through a small straw vs a large straw.

In terms of turbos, where many people are in the wrong mindset is thinking of a turbo in terms of boost the turbo can spin off. Thats an absolutely incorrect way of thinking about it. You want to think of lbs/min, which is the amount of air volume a turbo can move.

When a turbo is maxxed out,that means the shaft RPM is maxxed out, just like your motor at redline. Overboosting a turbo, would mean potentially overspinning the shaft, wearing on the bearings in the turbo, and increasing heat (partially due to the fact that when air is compressed, it produces heat, and partially due to the mechanical stresses of overboosting).

That being cleared up, the GM K04 will push about 36 lb/min, but maxes out about (on the Cobalt) 24 psi, then the shaft speed gets too high. I would say that on a different car with a more restrictive system, 24psi would be safe... for the turbo itself.

NOW, we have to talk about that in terms of safety for the engine. Knowing that the turbo is putting off alot more heat at 24 psi, I don't know how well a stock motor would take that. In fact, I am a noob to Honda's, so I am learning about the motors as I go along. Seems to me the little D series can handle 300whp from a big turbo rather easily.

To say that though and compare say a disco potato (GT28RS), which is admittedly a small turbo, to the K04, which is even smaller, would be something we could learn from. The GT28RS, even being a "small-big turbo", will outflow the K04, thus creating less heat from compression, and less mechanical heat, because it can support a higher flow, at a lower shaft speed.

Now, from here on out, it gets severely technical. This is when I would introduce you to compressor mapping. Some of the more knowledgeable guys may know how to do it, but it is a very complex science. This is a little write up I did on the Solstice forums in my shops vendor section, if you are interested (hope you don't need an account to access that!). It breaks it down pretty well, I think, and even provides you with a spreadsheet to help you with calculations!

I CRX I

i was actually basing my PSI off a website that drew this calculation from the compressor mapping for this exact turbo, he also mentioned the max RPM's (which i cant find now) but wouldnt it be safe to say that LBS/Min can be also converted to Lbs/Sq inch if measured at the turbo inlet (or is it outlet?) as the size and shape never changes? taking that into consideration, im sure the intercooler and the amount of CFM's the head can flow will play a big diffrence to the amount of PSI's read at the MAP sensor but im assuming it would change very drastically.


EDIT: here is the compressor map for this turbo

http://i260.photobucket.com/albums/i...g?t=1198288557

mkriebs

I am not sure how you could get PSI out of Lb/Min. There you are looking at POUNDS per sq inch, and POUNDS per minute, both pounds, yes, but I can't think of a conversion from min to inch. Might be some crazy way to do it, sure. I guess compressor mapping does use a pressure, so you could base it off that, though that is based on pressure from the turbo, and atmosphere, and it is also a ratio.

Too tired to get too in depth, but my link will explain that pretty well.

I CRX I

actually thats exactly what i was basing it off of, disregard the conversion comment as i was a bit confused but based on the map i posted above, could you conclude what the limit may be for this turbo before blowing flames into my motor? i read your write up but couldnt seem to put it all together with this map.