Guest butlersZ Posted September 21, 2004 Share Posted September 21, 2004 In case that don't work, http://hybridz.org/nuke/modules.php?op=modload&name=coppermine&file=displayimage&pos=-1860 Quote Link to comment Share on other sites More sharing options...
ToplessZ Posted September 21, 2004 Share Posted September 21, 2004 What about it. That picture has been posted several times. Beautiful car. Too bad it runs carbs. Quote Link to comment Share on other sites More sharing options...
HS30-H Posted September 21, 2004 Share Posted September 21, 2004 That picture was taken around 20 years ago, so it should be no surprise that it was running on carbs. butlersZ, your point was? Is this Show and Tell or Show and Ask? Quote Link to comment Share on other sites More sharing options...
Guest butlersZ Posted September 21, 2004 Share Posted September 21, 2004 Sorry, the rest of the post didn't come up, I have been having problems with my computer lately. Anyway what should have been there was the question of whether or not is that engine carb'ed or FI? I couldn't tell and wasn't sure, I was curious and never seen that pic before. I don't understand how it runs on carbs exactly. What type of carb's was it using? A friend of mine that is new to Z's and has caught the bug was asking me if he could turbo his S.U.'s and I told him no because they work on vacuum not forced induction. Then I go and see where people have put S.U.'s in front of a turbo and somehow it seems to work. Is that what the guy in the pic did? Does putting the carb in front of the turbo create a supercharging effect? Quote Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted September 21, 2004 Share Posted September 21, 2004 Looks fuel injected to me. I'm wondering how the carbs could be on the pressure (output)side of the turbos. My computer isn't that great, but it looks like injector rail and injectors between the intake manifold and the head. I don't see any carburetor(s) on the suction side of the turbo. It would be kind've difficult to find a carburetor that could operate at that fuel pressure level and overcome boost to get fuel into the intake. Man, there sure isn't much extra room under there. Quote Link to comment Share on other sites More sharing options...
HS30-H Posted September 21, 2004 Share Posted September 21, 2004 OK - since that is my picture, I had better tell what I know about the car and the engine ( butlersZ - I don't know where you got the pic from - but it was originally posted on this site in relation to one of the O.S. Giken threads ). I rode ( not drove ) in the car back in the mid 1980's. It was built by a garage called AUTO SELECT of Osaka, and was something of a street battle / 0-400m warrior. Many of these small tuning 'garagistes' were trying new things and testing them on the street at that time, and it was just around the period when proper FI was taking over from carburettors in these Japanese street-tuning 'wars'. Spec. on the engine was as follows: O.S. GIKEN TC24-B1 twin cam 24-valve crossflow head conversion. L28 block bored to 89mm ( approx. 3 litre capacity ). L28 Crank. F3 type FJ20 Con Rods. Forged FJ20 Turbo type pistons. 2mm metal head gasket. 9.0:1 compression ratio ( ! ). Hand fabricated 50.8mm equal-length tubular exhaust manifold. 89mm hand fabricated straight-through muffler system. Dual-layer Intercooler with 50mm piping. Twin KKK K26-3663G Turbines ( 'Formula One' spec ). Three 50mm OER blow-through type carburettors, with 6 sub-injectors in inlet manifold controlled by a Sanyo Kiki 'D-Fit' computer . Red line was 9000rpm. It was quite powerful, as far as I remember ( ). That was the best part of twenty years ago now......... Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted September 21, 2004 Share Posted September 21, 2004 OK - since that is my picture' date=' I had better tell what I know about the car and the engine ( butlersZ - I don't know where you got the pic from - but it was originally posted on this site in relation to one of the O.S. Giken threads ). I rode ( not drove ) in the car back in the mid 1980's. It was built by a garage called AUTO SELECT of Osaka, and was something of a street battle / 0-400m warrior. Many of these small tuning 'garagistes' were trying new things and testing them on the street at that time, and it was just around the period when proper FI was taking over from carburettors in these Japanese street-tuning 'wars'. Spec. on the engine was as follows: O.S. GIKEN TC24-B1 twin cam 24-valve crossflow head conversion. L28 block bored to 89mm ( approx. 3 litre capacity ). L28 Crank. F3 type FJ20 Con Rods. Forged FJ20 Turbo type pistons. 2mm metal head gasket. 9.0:1 compression ratio ( ! ). Hand fabricated 50.8mm equal-length tubular exhaust manifold. 89mm hand fabricated straight-through muffler system. Dual-layer Intercooler with 50mm piping. Twin KKK K26-3663G Turbines ( 'Formula One' spec ). Three 50mm OER blow-through type carburettors, with 6 sub-injectors in inlet manifold controlled by a Sanyo Kiki 'D-Fit' computer . Red line was 9000rpm. It was quite powerful, as far as I remember ( ). That was the best part of twenty years ago now.........[/quote'] did it ever set any timed runs or produce any numbers that you know of? and what cams were used? custom ones made by O.S. GIKEN? mike Quote Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted September 21, 2004 Share Posted September 21, 2004 Wicked. Quote Link to comment Share on other sites More sharing options...
HS30-H Posted September 21, 2004 Share Posted September 21, 2004 Sorry, I don't have any other data other than my 'ass dyno' readings........ It was a long time ago......... Quote Link to comment Share on other sites More sharing options...
slownrusty Posted September 22, 2004 Share Posted September 22, 2004 Just to add my 2cents. I bought several sets of OER Racing sidedraft carbs from Japan and these were the carbs of choice when running a blow through turbo carb set-up. I have since sold all these awesome sidedrafts but still have the original 1982 brochure. These OER sidedrafts will see 14psi all day and they can take the odd 18psi spike! Howz that for ole skool!! Interestingly I also had several sets of Group A FJ20 rods that I also imported, some great factory produced items. Yasin Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted September 26, 2004 Share Posted September 26, 2004 If only Japan was more open with their aftermarket -Ed Quote Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted September 27, 2004 Share Posted September 27, 2004 So do the "sub injectors" kick in when there is positive pressure in the throat(s) of the carburetor(s) because I still don't understand how the higher pressure air in the intake can draw in fuel from the lower pressure carburetor(s) jet(s). Unless, they have a fuel pump that supplies a higher pressure than the boost level. I know the velocity of the air over the jet(s) draws the fuel in on a normal carburetor, but isn't that because the fuel in the bowl is at a higher pressure than the intake? Is there some variable pressure fuel pump that beefs up the fuel pressure under boost conditions? Wouldn't the higher pressure in the manifold force the fuel back into the bowl and possibly back to the tank? I've been to school for an A&P license and completed every course except for non-destructive testing, and still can't understand how a carburetor can work on the output side of a turbo. I haven't actually seen one in action. Does anyone in Louisianna have one of these setups? 81zxturbo(now has 130mph speedo! Rock and roll!) 95slobaru Quote Link to comment Share on other sites More sharing options...
cheftrd Posted September 27, 2004 Share Posted September 27, 2004 The carb "sees" pressure in the runners and the float bowl at the same time due to a port in the front of the carb that's open to the surge tank. The OER carbs even have an inlet for a hose into the float bowl. Therefore, the carb works just like it would at atmo pressure. The fuel system requires a high pressure (efi) pump and a low pressure carb regulator. The difference is that it has a return line like an efi regulator so it can bypass the excess fuel from the high pressure pump (There are several different regulators that work in slightly different ways) It also has a boost reference port above the diaphragm that's connected to the surge tank. The fuel pressure will rise 1 psi for every 1 psi of boost. Therefore, if your static pressure is, say, 5 psi, at 10 pounds of boost there will be 15 psi of fuel pressure. Once again, it's acting exactly like an atmo engine, only the air is more dense. Here's where you run into problems with blow through carb turbo setups; Regardless of what people tell you about the turbo blowing air into the engine, that's not how it works. The turbo pressurizes the entire intake tract. If the engine has a 3000cc displacement, every 2 revolutions in atmo trim it displaces 3000cc of air. It only displaces 3000cc of air at 30 psi of boost as well. The difference is the air is more dense at 30 psi of boost. Carburetors do not see air density, they only see flow (signal) through the venturis. Therefore, If you jet the carb to run the correct AFR at WOT at 20 psi of boost at 5000 rpm, it will be super rich if you're trying to hold the engine at 5000 rpm at part throttle and no boost. At low boost pressures you can find a happy medium of rich one way and lean the other, but as the boost increases, so does the AFR spread. Here is where sub injectors come in. They also require the use of a high pressure pump (EFI), only they use an EFI regulator to maintain high pressure. This regulator is also boost referenced. A good sub injector controler will allow you to trim the injector pulse width, starting small at around 3-4 psi of boost and increase the amount of fuel as the boost rises, to keep the AFR constant. IMO, this is old school junk that had it's place in it's day. With the availability of cheap EFI, there's no reason to be running this set-up, other than nostalgia, if you're trying to make substantial power. Blow through carb turbo set-ups are a PITA to keep running correctly at high boost pressures. The fuel system becomes overly complex. Been there done that. Matt Hutchens Motorworx Race Systems Quote Link to comment Share on other sites More sharing options...
slownrusty Posted September 27, 2004 Share Posted September 27, 2004 Chef...wow good to see you on here!!! Taking a break from 4AGs? Great write up BTW! Yasin Quote Link to comment Share on other sites More sharing options...
cheftrd Posted September 27, 2004 Share Posted September 27, 2004 Chef...wow good to see you on here!!! Taking a break from 4AGs? Great write up BTW! Yasin Yea, the 4AG is still my favorite all-time engine, but I spend 80% of my time putting RB26's in other cars. Bummer...... Quote Link to comment Share on other sites More sharing options...
slownrusty Posted September 28, 2004 Share Posted September 28, 2004 So when can I ship my 280ZX across for you to work your RB26 cuisine on it....LOL!! Yasin Quote Link to comment Share on other sites More sharing options...
olie05 Posted September 28, 2004 Share Posted September 28, 2004 cheftrd: great info! Perhaps this should be a sticky Quote Link to comment Share on other sites More sharing options...
HS30-H Posted September 28, 2004 Share Posted September 28, 2004 IMO' date=' this is old school junk that had it's place in it's day. With the availability of cheap EFI, there's no reason to be running this set-up, other than nostalgia, if you're trying to make substantial power. Blow through carb turbo set-ups are a PITA to keep running correctly at high boost pressures. The fuel system becomes overly complex. Been there done that. Matt Hutchens Motorworx Race Systems[/quote'] If you're going to make a 'sticky', then this is the only bit you really need...... Quote Link to comment Share on other sites More sharing options...
cheftrd Posted September 29, 2004 Share Posted September 29, 2004 IMO' date=' this is old school junk that had it's place in it's day. With the availability of cheap EFI, there's no reason to be running this set-up, other than nostalgia, if you're trying to make substantial power. Blow through carb turbo set-ups are a PITA to keep running correctly at high boost pressures. The fuel system becomes overly complex. Been there done that. Matt Hutchens Motorworx Race Systems[/quote'] If you're going to make a 'sticky', then this is the only bit you really need...... A little clarification on this: Notice I said "if you're trying to make substantial power" and "high boost pressure". There's nothing wrong with blow through carb systems if you're just looking to run around 10 psi on your "L". If you already have a set of carbs, you can save considerable money over the cost of an EFI system, and if tuned correctly, the max power curve won't be that different. Around 10 psi of boost can be tuned to run at WOT and will still run well at part throttle, although it will be rich, and you're gas milage will suck. At high boost pressures, it becomes a very risky adventure, at best. Lose a float bowl gasket (happens all the time at 20+ psi) and you're going to saturate the engine room in a gasoline mist . If you have a slight leak, even at low pressures, you're going to be chasing misfires, bogs, and all kinds of tuning demons. If one carb doesn't get boost in the float bowl, it will never pass gas into the booster. Two cylinders will not run. Quote Link to comment Share on other sites More sharing options...
cheftrd Posted October 1, 2004 Share Posted October 1, 2004 I know this thread has been seriously hijacked , but one last word to the wise on carb-turbos. This mainly applies to higher power engines, but when running a long duration cam in a low compression engine with carbs, it is a PITA to get started. The low comp in combination with the cam will create an atmosphere where the mixture will not ignite. If you hit the accelerator pump, the air is not moving fast enough and the surfaces are cold which make for poor atomization. This in combination with no squeeze and it will be one of those cars that "you have to know how to start it". It's not uncommon for a 6-700hp carb-turbo L to have to crank for up to a minute to fire, let alone start. Matt Quote Link to comment Share on other sites More sharing options...
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