Mikuni Blow thru --Cartech

[madkaw]

I know this is a long shot, but does anyone have any info on the Cartech mikuni blow thru set-up. I would love to find a copy of the installation of this set-up. I have contacted cartech and they said all that stuff was destroyed when they moved offices.

[Sam280Z]

I've attached the instructions for the 280Z conversion. Joel sent this to me many years ago. He got it from Cartech. They said it was all they had at the time. The new Mikunis I have listed in the parts for sale section were part of a Cartech kit that never got installed (I'm pretty sure).

 

Sam

Cartech.pdf

Edited October 12, 2010 by Sam280Z

[turboHLS30]

Yea that's the same thing that I sent you. It's actually kinda useful it just doesn't have any info on the Carbs.

[madkaw]

Thanks Sam ,and as Shane said, he sent me that info. I wish it was for the Mikuni set-up.

 

Sam , you said the Mikunis are for the cartech set-up specifically-do you know if the jetting is set-up for the blow thru and does they have different floats?

[SHO-Z]

From what I have read the cartech is just a box. It is not like the HK that uses a baffel to increase the pressure in the float bowls and richens the mixture under boost . The Mikunis have the same floats as the SK Racing and are more heavy duty for boost. Do a search on the subject.

[Sam280Z]

From what I understand, the floats do not need to be changed. I'll look at the jetting that was in the carbs and get back with you, but if I remember correctly, they had the standard Mikuni jetting in them. The reason I think they were part of cartech kit was because of the shipping label on the original box and the fact that there were long socket-head cap screws included - like to hold on the cartech plenum.

[Sam280Z]

Look at post 42 in this thread: http://forums.hybridz.org/index.php/topic/61291-hks-plenum/page__hl__%2Bhks+%2Bcartech__st__40

Edited October 14, 2010 by Sam280Z

[madkaw]

This is the problem when considering this set-up, there is not much info out there for the non-expert mechanic. I read that this Cartech set-up puts boost out like an on/off switch which cause lean issues. This might be a waayyy cooolll set-up in it's time, but it might be more expensive and time consuming then just going from carbs to EFI. Yes there are threads about the Cartech, but no specific instructions.

[SHO-Z]

I am surprised that Tony D has not logged into this discussion. As he says EFI is the way to go. He is the expert on blow thru. I was working on a supercharger/ blow thru set up. From what I have researched getting a higher pressure in the float bowls that the carb throats is one of he major design considerations. As I said HSK used baffels, I was planning on using a tubing set up and the pressure loss going through the intercooler. From my reading the stock jetting will work if the bowl pressure is higher than the carb throats. Now I am no expert and have really stopped working on my project, due to lack of interest. My z has either been sitting in the garage or in a trailer for better than a year.

[madkaw]

I saw some of your posts and pictures when doing the research. This blow thru set-up is very cool, but I think I will be over my head. I think I will stick to my original plan to go from SU's, to Mikuni's, then EFI TBI's and then maybe turbo charge that!!!! I think with the advantages of wide band O2 set-ups and edis you could maybe help the blow-thru set-up work better without a lot of guessing on your afr's. This doesn't change the fact that the Cartech box is too small or the set-up is not as driver friendly as what I want for a semi-daily driver. Tony would say-go efi is the better way to go-and I agree. The money spent on this set-up would be much more cost effective to buying a wideband/O2 and EDIS and getting the optimum tune on my SU L24 now and slowly work towards a MS controlled EFI.

[Sam280Z]

I contemplated doing the blow through carb thing years ago. Based on the advise of those who had been there / done that, I ended up using TWM ITBs on two motors - one is a 3L and the other 2.8L. The 2.8L is on the road now and I'm in process of tuning. The 3L is for my fancy project that has been on the rotisserie for far too long.

 

Right now I have cartech plenum and think I may be experiencing that "transient lean" that TonyD speaks of in post 16 and the fuel mileage in post 37 (http://forums.hybridz.org/index.php/topic/61291-hks-plenum/page__hl__%2Bhks+%2Bcartech). I cannot source one HKS plenum, much less two - so I have drawn up plans in autocad based on the 3D modeling on MONZSTER's "monzster plenum" thread ) (post 143). I have a friend with a CNC mill and hopefully will build a couple in the near future.

 

TonyD, Is the main advantage of the HKS plenum the additional volume or the diffusing action of multiple inlets and routing of air? I'm wondering how much effort I should be putting into replicating those features for an injected setup.

 

Thanks,

Sam

Edited October 15, 2010 by Sam280Z

[Tony D]

Both. Thing is the diffusing action is not as important on a plenum blowthrough style, but is on a plenum with ITB's. The ITB's as MONZSTER showed withthe CFD will get uneven flow from the introduction of air to the plenum, so diffusing and straightening it is beneficual. A Cartech Box is just a box, worse than the flow characteristics of the stock N/A EFI plenum when it comes to distributing air to the cylinders.

And the stock EFI plenum has been shown to produce 500+ HP with little modification at all.

If you ahve ITB's then the diffused plenum will giveyou more even air distribution. That means one cylinder won't run lean or rich compared to it's sisters.

 

At 100HP a hole, that makes a difference. Especially on 5 & 6!

 

Look at Yetterbens comments as he lived and learned. Jetting Jetting Jetting. The jets the guys ran in the Cartech boxes were humongous compared to what I would run in mine. Or what I had to run after going smaller and undiffused.

[turboHLS30]

Sorry to kind of high jack your thread Steve, but Tony, I'm in the process of removing my Cartech turbo kit to sell it but I'm gonna run the triples open with velocity stacks. Would there be a problem with me running them without the turbo kit?

[Tony D]

Just get some air correctors and main jets. You will be making less than 350HP and the main jets will be humongous for what you need without the turbo.

 

My car had two sets of jets, I could swap from Turbo to N/A in about 45 minutes including the jet swap.

 

The size jets yetterben was running were an order of magnitude larger than what we ran on our record holding N/A Bonneville car!

 

Other than jetting down, that's about it... I blew my turbo at MSA on Saturday, and was N/A at the car show Sunday Morning sporting a Red ITG Air Cleaner and plastic sharks on it. "Wasn't this thing turbocharged at the Auto X yesterday?"

 

Yes, yes it was. Got up at 4AM, and left the house at 5AM as an N/A. Piece of cake.

[chicago240z]

My room m8 just bought a 280 that was bought in an estate sale with a brand new cartech /mikuni system with a msd6 and turbo timer would this setup be better than a vq35 swap I want more h.p. but dont want to sacrifice torque any one actually used this system setup correctly?