New2TheZ2006 Posted December 18, 2006 Share Posted December 18, 2006 OK, Lots of INFO. I Have a bored out 2.8 with injection (75 280z) I was thinking about taking off the injection and putting on carbs. Is this a good thing or bad? I am just getting into this who Z thing, Hence the name. I would like input on the swap, to swap or not to swap. I am looking for fun car to drive, in process of body work paint and then new interior suspension and brake upgrades then out of money for a while. Thanks pS willing to get a used set carbs and intake for the swap though if good upgrade Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 18, 2006 Share Posted December 18, 2006 The stock injection sucks really bad. It is very primitive and the AFM is a big restriction. You can however swap to a stand alone FI system which will rid you of all of the stock issues and problems. That is kind of a DIY thing, so you need to have a lot of familiarity with FI in order to get one of those systems working properly. Check the megasquirt forum. If that's not your thing, carbs are pretty easy to get in the ballpark and in my opinion, even a set of SU's would be a step up from what you have right now. If you're looking to make a lot of power, the triples have a definite advantage over the SU's, and 44's or 45's have a definite advantage over 40's. If you want the best of both worlds, you can get triple throttle body injection that bolts onto a triple carb manifold. Several people here are running that setup, and it is probably the ultimate for NA induction. Quote Link to comment Share on other sites More sharing options...
bjhines Posted December 19, 2006 Share Posted December 19, 2006 I will say that the SUs perform very well indeed... You need the later model N-36 intakes for the SUs... The biggest issue that seems nearly unsolvable without buying the Z-Therapy rebuilt SUs... is the throttle shaft leaks... Forget about finding a good factory set... The Z-therapy SU carbs are THE BEST SOLUTION for a new Z owner... They work like magic... That said.... The triples get some attention... especially if you open up the airbox and let them howl... I swear the triples make as much noise in front as the exhaust does in the rear... You will REALLLY turn some heads at a Honda meet... An aggressive cam also helps them make noise... I would go for a new set of triples... unless you know how to look a set over and determine their wear factor and rebuildability... also look for consecutive serial numbers (or very close at least)... The DCOE 152s are the latest and most managable versions of the Webers... The Mikuni-Solex versions are fantastic... they are often harder to find here in good shape or streetable form... Quote Link to comment Share on other sites More sharing options...
HakosukaJD Posted April 21, 2007 Share Posted April 21, 2007 Running Triple Solex PHH44's, 225air, 175fuel, 50 pumps, and 60pilots (yeah...I've heard....should be between 40-45) on what I believe is a stock L28. but... Very mild stumble when going on the mains and after about 20mins of running (from cold), A/F is hovering right around 14.6. At WOT, its around 12.5 (via Innotech W/B). When its cold, A/F idling is around 11.8-12.4..... Gas mileage sucks. I have 1.5 turns on the idle screws, engine idling at about 900RPM. I don't mind the stumble...it is VERY slight....but the mileage is in the neighborhood of 10mpg.... Will dropping to 45's on the pilots help out here? With mid 14's at idle after it warms up, will it go too lean? Also...anyone have any luck getting the LM-2 RPM kit to work right? I went with a hard wire setup on the main unit, ground the LM-2 to the same place as the main unit and am sensing off the coil with a 50k pot to adjust the input voltage..... can't get a clean signal.... I've asked on the innotech site as well....might get a faster answer here.... Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 21, 2007 Share Posted April 21, 2007 I think you need larger pilots and smaller pumps. In my experience the smaller the pilots the larger the hesitation, and putting bigger pumps in makes it worse. Larger pilots may run fat, but they smooth the transition to the mains. Quote Link to comment Share on other sites More sharing options...
HakosukaJD Posted April 23, 2007 Share Posted April 23, 2007 I think you need larger pilots and smaller pumps. In my experience the smaller the pilots the larger the hesitation, and putting bigger pumps in makes it worse. Larger pilots may run fat, but they smooth the transition to the mains. The hesitation isn't too bad. The issue is this. I'm getting 9.4 mpg. ...it sucks in and of itself.....but I'm also paying close to 4 bucks a gallon. Do I have a fuel leak? Or is this a result of running at 12.5:1 all the time....? Quote Link to comment Share on other sites More sharing options...
Zmanco Posted April 23, 2007 Share Posted April 23, 2007 At the risk of stating the obvious, you either have a very heavy foot, or are very rich, or both. I see 10 mpg on the track, but can get as much as 21 on the highway with a very light foot with 40 mm DCOEs. What do your plugs look like? How about carbon buildup on the back of the car near the exhaust? Those can be telltale signs of running too rich. Would be better to get access to a wideband O2 sensor. Given the rate at which you are spending $$$ on gas, might be a good investment to visit a dyno that knows how to tune your carbs. I'll guess you'll get the tuning money back in a very short time. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 23, 2007 Share Posted April 23, 2007 I was also getting low to mid 20's on the highway with 44s. He did say he has a w/b O2, and it sounds like its tuned in about right. Not sure what the problem is. Quote Link to comment Share on other sites More sharing options...
datman Posted April 23, 2007 Share Posted April 23, 2007 225 air 175 fuel!!! mine had 190 air/135 fuel and was still on the rich side. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 23, 2007 Share Posted April 23, 2007 225 air 175 fuel!!! mine had 190 air/135 fuel and was still on the rich side. The jets depend a lot on the cam used. Bigger cam, smaller jets. I think I had 215/155s in mine. Besides 80% of your drive around town fuel economy comes from the pilots in my experience. Quote Link to comment Share on other sites More sharing options...
Dave240Z Posted April 23, 2007 Share Posted April 23, 2007 I would tend to agree with the other advice offered here, those jets seem huge for a relatively stock L28. FWIW, back in the day I was running 145 mains and 180 airs with 55F9 idles on my then mostly stock L28. I was able to easily get 20+mpg on the highway and mid teens in town. On my Rebello 3.0L with a crazy cam, I’m using 155mains & 60F9 idles which are still a little rich according the A/F ratios I’ve seen while on the dyno. Also, don’t underestimate the difference a seemingly small jet size adjustment will make, both in drivability and efficiency. Little changes can have big effects on these carbs. 12.5:1 is great for WOT, but you should be much leaner at idle. That’s a lot of wasted fuel and can really impact your city mileage. I would say you need to drop the jet sizes across the board. Just looking at the sizes, all of them seem too big to me, although the readings you have seem to indicate otherwise. I’d be interested in seeing a complete A/F graph from idle to redline. That will help explain things a little better. Going with the LM-2 is the right way to go about this, but make sure it is working correctly before blindly following the readings. Technology is great, but it shouldn’t replace your brain entirely. Sort of like the guy who crashed his car by blindly following his in car navigation system which told him to turn left right into a building! Just for the record, what are your timing settings? How about spark, are you getting a good clean spark? Quote Link to comment Share on other sites More sharing options...
srgunz Posted April 23, 2007 Share Posted April 23, 2007 Running Triple Solex PHH44's, 225air, 175fuel, 50 pumps, and 60pilots (yeah...I've heard....should be between 40-45) on what I believe is a stock L28. I am running the same motor as you (stock). I now have 135fuel with 180air and 60pilots. No hesitation and fairly good mileage considering I have a 4:11 rear gear ratio. Try my set up. I think you will like it. Quote Link to comment Share on other sites More sharing options...
datman Posted April 24, 2007 Share Posted April 24, 2007 It did have a wild cam, decent exhaust manifold and CR of 10.5:1, ignition was 36 deg full in with vac advance disconnected. Pulled like a train from low down all the way to 7k. My idles were also 55f9's. Quote Link to comment Share on other sites More sharing options...
HakosukaJD Posted May 14, 2007 Share Posted May 14, 2007 Timing looks to be 12deg at idle, 34 deg at 3k RPM. I finally managed to get my RPM logging working now....had to set it by engine RPM rather than using soundcard output. Ever since I hooked up the ground on the LM-1 to the block ground, the RPMs at idle have come up by about 100. Here's a spot of my LM-1 Datalogging A/F spikes come right as I shift, no surprise there. The really odd one is where the A/F goes to 20:1 right in the middle of a WOT run (misfire?) What do you think? Quote Link to comment Share on other sites More sharing options...
dv82xl Posted December 19, 2007 Share Posted December 19, 2007 hum...I had tripple 48 DCOE on my L24 too MUCH carb - you want em? Quote Link to comment Share on other sites More sharing options...
twistex Posted February 22, 2008 Share Posted February 22, 2008 Bought a set of 3 45mm sk racing carbs. for 500! Good deal considering there brand new. The jets in there are as fallows f11 tubes 180 air 130 fuel 55 f8 idle I'm going to play with them today. I have them all sync'd and I'm going to bottom out my mixture screws and turn out 1 turn and no more then 2 or so to see if i have the right sized idle jets for my motor and setup. This is what the carbs came with. From the looks of it, they use weber jets. I have a 3.2 diesel block, diesel crank, z20 rod, 90mm ka pistons, 480/280 camshaft, ported polished maxima head with big valves. I currently haven't driven on this jet setup so I cant tell you how it runs lol. I need exhaust first. I will post back on what i find but, I'm hoping I wont have to change from f11 to something else because they are pricey! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 22, 2008 Share Posted February 22, 2008 I would suggest a larger cam to take advantage of the triples. Good deal though for $500!!! Quote Link to comment Share on other sites More sharing options...
Careless Posted February 22, 2008 Share Posted February 22, 2008 I have a 3.2 diesel block, diesel crank, z20 rod, 90mm ka pistons, 480/280 camshaft, ported polished maxima head with big valves. I currently haven't driven on this jet setup so I cant tell you how it runs lol. I need exhaust first. I will post back on what i find but, I'm hoping I wont have to change from f11 to something else because they are pricey! what kind of power you intend to make? that sounds like a nice setup, and the inexpensive purchase of those carbs will make it all the better. nice catch Quote Link to comment Share on other sites More sharing options...
SHO-Z Posted February 22, 2008 Share Posted February 22, 2008 I do not know if these are stock or what on my SK Racings I have: 45 MM Carbs 34 MM Venturi Jets Mains 135 Tube F11 Air 165 Idle 50 I went to buy a 5 spd for $75 and bought the SKs for $100, not bad $175 for carbs and tranny! Now all I have to do is get off of my dead ass and install them! Quote Link to comment Share on other sites More sharing options...
twistex Posted February 23, 2008 Share Posted February 23, 2008 I would suggest a larger cam to take advantage of the triples. Good deal though for $500!!! true that! you have any suggestions on the size and actually I have 3 cams 460 270, 480 280, and a 516 227 @.50th 294 adv! I actually think i have the smallest one in there right now. I will try the 516 lift cam but i will have to check my wipe pattern. May need to put different sized lash pads. Quote Link to comment Share on other sites More sharing options...
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