Blow through turbo setups?

[280zex]

If you know Holley carbs enough I have a post about the mods for blowthru in this post..

http://forums.hybridz.org/index.php/topic/87310-blowthrough-280z-dyno-resultsand-pic/

[letitsnow]

Dirtbike and snowmobile carbs gibe better throttle response than reg carbs do- for one- for two, it would almost be like fuel injectors one per each cylinder and it would be like itbs again one for each cylinder. Also with carbs instead of fuel injection I am honestly not as limited.

 

Do you have any experience tuning (blowthrough) carbs? How about the carbs you are looking a at? If not, I'd go with something more proven, like mikunis or a holley, there is a lot of support for tuning blowthrough holleys on other forums. With the bike carbs you will pretty much be on your own, and they'll need a significant amount of tuning to be anywhere near close.

 

If you don't already have an in depth understanding of carbs, efi might be easier to learn.

 

As far as getting the carbs, check motorcycle salvage yards and ebay. You'll probably either have to make or have made some adapters to go to an existing manifold.

 

Also, most 2 stroke carbs don't have an accelerator pump, so you can rule all of those out.

Edited August 13, 2010 by letitsnow

[Tony D]

Every question you have asked has been answered in the archives already, including about your fuel injection pump and linkages.

 

If you think bike carbs are a better way of doing it than EFI....

 

Well...bood luck to you. You are making statements about using things for reasons which are neither rational or particularly well-thought out. If you can't handle the linkages, what makes you think the tuning of individual carbs is within your realm (or that EFI is somehow more complex?)

 

I ran blowthrough for years. I changed to EFI because tuning was easier.

 

But you will have to learn that for yourself. Read Yetterben's thread on his build.

 

This is also in the archives as well.

 

(BTW, "Dirt bike carbs" are no more responsive than any other carburettor, if you think so, you simply don't know enough about carbs to undestand the folly of your statement! It goes hand in hand and is in the same vein as someone making the statement: "Carbs are Easy"---anybody making that statement has neither tuned carbs seriously, or has very low standards of acceptable performance. "It starts it runs, it doesn't puff black smoke much." is not acceptable performance in this company...generally speaking!)

[vega]

It is what I was told by many motorcycle guys that dirt bike carbs had better throttle response is all. as far as getting the fi to be playable in the car aside from megasquirt which i took some time on their site as well as diy auto tune. and read a lot. I also have experience in tuning hondas and dsm cars with obd1 that for me is VERY simple just use chrome and there you go.

 

The best setup i have seen on here for fi is a member called 6shooter- he has switched to a gm computer and made his own crank trigger setup. To me making my own crank trigger is a bit iffy FOR ME. the thing i would do IF this would work is use the electronic distributor I have and get a signal from that to send to the ecu but I haven't a clue persay how that would work. If you have some insight on using the fi more than i do as far converting and old engine to newer style fi setup so it is easier to tune please enlighten me because from all the searching I have done I have found very little in this aspect to any kind of ease behind it. Because it comes down to this convert it to carbs or convert it to a newer style fi setup- at least as far as I can tell.

 

The other thing I am going to attempt is a t5 swap from the zx models for the strength in the trans with a short shifter kit.

[Tony D]

Apparently Anoka MN is an ESL location, as nothing proffered seems to have been heeded. Just the insistent counterpoint.

 

Ah well, good luck to you. As they say: "You can lead a horse to water..."

[Bernardd]

It is what I was told by many motorcycle guys that dirt bike carbs had better throttle response is all. as far as getting the fi to be playable in the car aside from megasquirt which i took some time on their site as well as diy auto tune. and read a lot. I also have experience in tuning hondas and dsm cars with obd1 that for me is VERY simple just use chrome and there you go.

 

The best setup i have seen on here for fi is a member called 6shooter- he has switched to a gm computer and made his own crank trigger setup. To me making my own crank trigger is a bit iffy FOR ME. the thing i would do IF this would work is use the electronic distributor I have and get a signal from that to send to the ecu but I haven't a clue persay how that would work. If you have some insight on using the fi more than i do as far converting and old engine to newer style fi setup so it is easier to tune please enlighten me because from all the searching I have done I have found very little in this aspect to any kind of ease behind it. Because it comes down to this convert it to carbs or convert it to a newer style fi setup- at least as far as I can tell.

 

The other thing I am going to attempt is a t5 swap from the zx models for the strength in the trans with a short shifter kit.

 

Why don't you grab a turbo cas/oil pump drive and use a chipable nissan ecu. You can tuneable efi for under 300 bucks.

[Tony D]

Why don't you grab a turbo cas/oil pump drive and use a chipable nissan ecu. You can tuneable efi for under 300 bucks.

 

One time, at Band Camp, I heard this story about Cheap Affordable EFI...

[vega]

There has NEVER been a chipable nissan ecu... yeah... about that...

[Tony D]

Uh, yes there has... you just solder the chip (or if you are spunky, the chip holder) onto the board.

They are chippable, just not in the GM sense of the word.

[vega]

what chip are you removing from my understanding there is no 27 pin eprom chip.

[Xnke]

You're right...it's a 24 or 28 pin chip. Look up Nistune, Vega.

[Tony D]

With enough people out there pre-nisstune hacking the stock Hexidecimal EEPROM via romulator and prom burners, I'm surprised someone would come up with that kind of a comment.

 

Xnke is 100% correct, Nisstune gives you a Megasquirt-Like interface and the ability to burn the prom on-the-fly.

 

And you are correct, there is no 27 pin EEPROM. They all have even numbered legs...far as I know. Why would it have to be 27pin specific? By GM-Sense of the word I meant that GM puts a PROM-Holder on the ECU Board, allowing an EEPROM change in the field without exchanging the whole ECU. GM thought ahead. Ford chose to have a field flash programmer.

 

Now, everything is available through the OBD Port and is reburnable that way---CONSULT can do the same thing with Nissan Boxes. You don't NEED a replaceable chip to have a programmable EFI system on your OEM ECU. On the older stuff, it just made hacking the Hex easier by reading the files, changing values, and reburning/replacing the chip to see what changed.

 

But that was the stone age, Eh Gimli Boy?

[Bernardd]

I think or thought that he was kidding that's why I didn't reply..... and it's supposed to be nice and cool for friday night under the lights. Car is on the trailer ready to and you're welcome to join me.

[Tony D]

The guys in Regina just have to cut me a P.O. and this time I'll drive over instead of fly direct!

(Worked at the Co-Op for a couple of weeks in June...)

[Bernardd]

Ok, let me know when you're on the way over.

[vega]

nistune is a daughter board i have SOME but little experience with it on the 240sx platform. 27 pin is what most manufacturers use with their obd1 system with their eprom chips so you can take that out and put in a zif socket and a burnable chip or chip emulator like the moates.net products.

 

From my understanding unless things have changed nistune is not available for my 1978 ecu. If it is or was i love nistune it works great!

[John Scott]

wow. all it takes to tune a carb is to turn a screw and adjust a float, maybe change a jet if you are mechanically inclined...lol!

What was I thinking reconfiguring every emulsion hole,jet,and bleed on my n/a carburetor? That's with an E, by the way. Blow through carburetion is an art as much as a science.

 

Some random considerations, admittedly my experience is dated.

You realize carbs need little psi but high volume. With A Holley, for example you'll want to keep the fuel pressure about 7 psi over the boost. 10 psi = 17 fuel pump psi. You'll also need a way to bleed the pressure off immediately when you are running full boost and then let off. Washing down the cylinders with over rich mixture, blowing the needle and seat, or worse yet hydro-locking the engine is ugly. Don't ask how I know. Most carbs can't handle high pressure at the needle and seat anyway. Not enough pressure and you make wiffle ball-like piston tops. Have a boost regulated regulator with return line. Questions: Can the carb body, float bowls be designed to handle boost. Will floats collapse? How about the fuel curve designed in the carb itself. There are many bleeds, emulsion holes, powervalves, venturi that are designed for n/a. Add boost and you've upset the equation. You do want to drive this other than WOT, right?

 

Check here for some basics: http://www.theturboforums.com/smf/index.php?PHPSESSID=f45d653824f89440d10d1d6663f3d4b7&board=13.0

When Innovate forums gets up and running again, check them out as well. http://www.innovatemotorsports.com/forums/

Beyond the blatant naivete, your idea sounds really cool. I hope you can pull it off.

Edited August 19, 2010 by John Scott

[letitsnow]

nistune is a daughter board i have SOME but little experience with it on the 240sx platform. 27 pin is what most manufacturers use with their obd1 system with their eprom chips so you can take that out and put in a zif socket and a burnable chip or chip emulator like the moates.net products.

 

From my understanding unless things have changed nistune is not available for my 1978 ecu. If it is or was i love nistune it works great!

 

Check out the sticky about the z31 ecm swap.

[Tony D]

Wow, so the criteria for the turbo swap is you wish to retain your 78 ECU now? Wish that was stated earlier.

 

Like it was said before, you need to read some more. Especially about your R200 which you don't think can handle the torque of the V8...

 

As was stated, this is all well-covered previously.

[vega]

no that is NOT the criteria of the swap.... that makes no sense. My point was that nistune is not available for these the 280z ecu- one would have to- as previously stated swap to a z31 ecu. OR one could just swap to a gm ecu. I will NOT be retaining my stock ecu when the car is modified for any reason.

 

As for the r200 I don't think it can handle the tq of a low revving v8 without too much stress if the tires actually hook as I am working on the suspension to do so- I am not building a drift car where it doesn't matter. Now a higher revving v8 which the peak tq gradually comes in and toward the higher end of the tq curve I think it can handle. I just don't think the amount of hp I am looking for at that kind of rpm is plausible in a v8. I want about 7-8k rpm in the v8 so a 327 or smaller preferably a 302 which good luck there so either build a 283 or a 327 or a 327 small journal with a 283 crank (FORGED crank btw because anything past 5600 rpm is going to be too hard on a cast crank. So now JUST for a descent forged crank new we are talking about 1100 or so. Now lets make it rev even higher - lets just use a 283 with some great heads- well from my understanding (I could be wrong- I was told this by a builder) there is something about how small the pistons are in a 283 that are great for higher revving but have a hard time making hp because of the size of the head options available- which for my goals are going to make that a very expensive build. I have gone through and blue printed the price on engine builds and the like it seems that we are talking about 6 or 8 grand for the kind of power I would want out of a v8 where the kind of power of a supercharged or turbocharged l28 is a bit more attainable. Now if it was a low revving motor this would be WAY cheaper- but I just don't think that is a good idea from what I have read, my own personal experiences, and from talking to people in REAL life rather than just online. I hope that clears things up a bit- you come off a bit standoffish.

 

I am currently talking it over with a friend of mine about using the stock dissy with a gm ecu- seeing that it has a 6 tooth magnetic pickup design a gm ecu can read that kind of signal without using a crank trigger- THAT will basically BE the crank trigger. Which is pretty much how the ecu is already setup in this car, except that it does not have the far tunablity as the gm ecu i.e. using the moates ostrich real time chip emulator and chrome. What I need to figure out is if I NEED to use a gm icm or not. That part is what escapes me at this point.

Edited August 19, 2010 by vega