Serban

Here's a short drive with the turbo setup. The Draw through is on an L24 that I pulled out of a parts car I bought. Sat for a very long time, but after putting some MMO in the cylinders and letting it sit for a while, it came to life!

I had another thread on here I started a few years back, then Photobucket decided to be the biggest troll of the century and block everyone's hosted photos from being linked, so it's easier for me to start a new thread with the old pics, and latest updates of my car. I'll start again, I got this car October 2013, and in these last few years, it's come a long way, and had a few transformations as far as engine setups. Day 1, tow it ~200 miles back home Not much of a looker The engine was a mess, only ran on 5 cylinders. After a while, I started having problems with the stock EFI setup, as one would expect, so I decided to venture out in the world of carbs, first up, stock SUs, then triple webers, and lastly, a draw through turbo kit

I found the source of my exhaust leak... The turbo inlet flange has this channel in it (not really sure what it's for), and the new T4 inlet gasket I bought didn't fully cover it, which in turn made for a nasty exhaust leak. I'm using the one that came off the turbo in the meantime until I find another one. With that being fixed, I took the car for a drive, and it struggled to even make 4psi. I double checked everything then researched the wastegate hose placement. I'm supposed to run the hose to a boost source before the throttle plate. In this case, everything before the throttle plate has no boost. Tial does not recommend connecting it to the manifold, as vacuum could cause problems with the diaphragm, so I tried disconnecting the hose, and running it as it was before, without a wastegate, and got about 7-8psi. A little better. The wideband was around 13:1 afr, but without a wastegate, this turbo just wants to make more boost, and I have a feeling it'll lean out. I may try connecting the wastegate again, and adding a boost controller. It has a 4-5psi spring at the moment. Has anyone that has run this setup been successful with using an external wastegate?

https://youtu.be/IA-Wr9WPeFk Here's a video of it starting up!

The L24 is in, and ready to go! I only get to work on the car a couple hours a night, so it took me about 3 nights from start to finish. Initially the L24 had low compression on a few cylinders (between 30-40psi). I put some Marvel Mystery oil in each cylinder, and after about 4 hours I tried again, and got about 150 across the board, seems promising! It starts and runs, and holds idle great! I have yet to drive it, I think there's a huge exhaust leak somewhere. I can't pin point it yet, but when you rev up the engine, exhaust smoke is coming from the manifold to turbo up pipe. So I'll probably have to pull it all apart and see how the welds are, or if there's a crack. But so far so good. Here's a few pictures from the swap!

Valves are 42mm and 33mm, looks like they're stock size.

Tony, your input is very useful, and I appreciate it. I'll see if I can find some time tonight to pull apart the SU carb and see if any of that's been done. If the dished pistons are a surprise, perhaps there are more? I was told 9k went into the engine build, just curious where all that money was spent, if that's an accurate number.

Hey everyone, it's been a while since I posted on this thread, but I finally got around to pulling the head off. Pistons look fine. This is an E31 block, and E31 head. It's got dished pistons which I'm told is not the stock piston on the E31, and the bore is 83mm. Pistons look clean with no sign of detonation. I haven't measured the valves yet to see if they're oversized. But what is everyone's thought on this? The head looks pretty clean. I guess next step will be to drain the oil and pull the oil pan off and investigate a little more. I still plan on cleaning this engine up and swapping it in with the Rajay turbo it came with, as long as it checks out. I'll also add an external wastegate. I don't like the idea the idea of not controlling the boost. I'm also not looking to shatter any records, I realize doing an EFI carb body would ultimately be the way to go, but I just want to keep this as it was 30 years ago. I don't want to spray any methanol, if the SU will handle 10-12psi without running lean, I'd be ok with that.

Nope, already did SUs and moved one to triple webers now.

Very cool z-ya, thank you for sharing those pictures. I can't wait to start digging into this engine, but I've been idle with it now since my other car decided to get a nice rod knock. I've got that engine torn apart at the moment while I wait for parts.. When that's all done, I'll start tearing into the L24!

21psi seems like a lot of boost and I'm surprised a single SU is adequate enough, even 17psi... This is a neat setup and I would like to run it. I thought about using my 280Z intake manifold and going EFI, but the E31 head does not have the holes to put a 280Z intake manifold on. Either way, I think a more modern T3 turbo and wastegate would be a better option than the hybrid Corvair turbo. I also found the Crown adapter for a Weber carb. Would that be a better suited carb vs. the single SU?

Tony, thanks for sharing, what are your thoughts of keeping this turbo setup (obviously with more modern fittings, etc.) vs switching to a proper EFI system. All this is dependent on if the engine is good, and if it was purposely built for turbo of course.

Greetings fellow Z enthusiasts! I just picked up a very very rough Z (which will go to the scrap yard), but it came with a supposedly built L24 with a draw through carb turbo setup. In my internet search, I found something similar, made by Crown many years ago. What I have is very similar, but the log manifold that connects the two carb manifolds is different, and looks custom made, also, very nice piece despite all the rust. The guy I bought the car from said the previous owner had about $9k worth of engine work done, I won't know until I pull the engine out and get it checked out. What I found interesting about this whole setup was the use of pipe fittings and valves everywhere, pretty sure this setup was done before AN fittings were available The carb inlet pipe has two nozzles in it that spray right into the carb, not sure if that's for extra fuel? A single SU carb doesn't seem adequate for a turbo setup in my opinion. The fuel line was connected to a T that goes to the custom made balance tube, and on one end was some kind of electric sensor, or switch? It could be that someone just stuck a hose on that fitting over the years to cover it, I don't know for sure. I also have an adapter for using a Weber carb with this turbo. I'd love to hear more from those of you who may have some info on this setup, it's pretty unique. If this is a fully built engine, and still good, I struck gold for sure! At that point I might just ditch the carb setup, and go for a more modern EFI setup. This will eventually make it's way into my 280Z which I recently converted to carbs since I was tired of all the EFI problems. Here's some pictures of this thing:

I wish I could say I've been driving the car more, but for the past 5 months, I've been plagued with fuel gremlins from hell. So much so, that I've decided to get rid of the stock EFI.....and go with a carb setup. I know the logical thing would have been to do a standalone EFI, but I was so fed up with troubleshooting one thing after another, I just wanted something...simple. Now, I've never worked with SU carbs, or carbs in general, I grew up in the era of fuel injection, but I wanted to try something different without spending a whole lot of money, so I got a set of 3 screw SU carbs, complete with manifolds and linkage. Pretty complete setup, but it was very rough looking, most folks probably wouldn't even bother with cleaning, and rebuilding these. One of the suction pistons was completely froze inside the dome, but over the last few days, I've been cleaning, and sand blasting parts, to make these carbs usable, and make them look somewhat nice. I have one more carb to sand blast, then I can start putting everything together. I already bought an electric 4.5psi fuel pump, I just need to wire that in, and hopefully soon, I can drive the car again. It truly is sad seeing it collect dust in the garage!

Thanks for the info guys.

I'm kicking around the idea of giving up with the fuel injection, and going to carbs on my 280Z. What's the going rate for a complete manifold and carbs? I'd prefer the round top SUs vs flat tops.

Let me run some tests first on my AFM, thanks for posting though.

I'll try to get some test numbers soon. Thanks for the info.

Trying to see if my AFM is bad, thought it might be the ecu, but even with a new ecu, the car is doing the same thing. Does anyone have a good and relatively cheap AFM in the $50ish range? Any more, and I'll probably consider doing a Megasquirt, and getting rid of the whole thing. My car is a '75 280z, if there's any differences in the later AFMs. Thanks!

Tried to start the car and it stayed on and idled fine, didn't flood out. Not sure what the deal is, but I'm leaning toward ecu. Fuel pressure with the vacuum line on was at 31psi.

I was just browsing through the Engine Fuel chapter, I'll take a look at it a little more tonight. I'll report back with results as I have time to work on the car. Thanks for guiding me in the right direction in trying to hunt down the culprit. I may start pointing fingers at the ECU though. As I mentioned once I unplugged it, and plugged it back in, the problem would resolve itself, but now its not.

I know the injectors are a little bigger than stock. The guy who made the rail for me tried to get something close to the original ones, I guess that's as close as he could find? I'll double check the fuel pressure if I can get the car running long enough. The AFM was adjusted as per the atlanticz instructions to lean it out a bit. Full throttle the AFR is in the low to mid 13s, however, idle is very lean (when running "properly" of course). ECU is stock. I'll pull the AFM and inspect it to make sure nothing came loose in there.

Pretty sure fuel pressure was in the mid 40s psi during this whole ordeal, but I'll definitely take a look at the fpr. I'm still using the stock one, but I've got an adjustable Aeromotive I need to install. BTW, I forgot to mention, the car has Ford 19lb injectors in a custom made rail. I've put over 10k miles on this setup, so I doubt it's the injectors. Anything else I should look for? The car has been pretty trouble free since I've had it.

Yesterday I tried to make it out to a yearly Nissan meet, and only got about a mile and half away from the house before the car died on me. Here's the back story, every once in a while, either at idle or while driving, the car would just flood out, wideband gauge pegged at 10:1, so much fuel that the car would just die, couldn't keep it running. My solution was always to unplug the ECU, crank it up, let it run a second till all that fuel was cleared out, reconnect ECU, and it was fine again! In the 2 years I've had the car, this happened maybe a handful of times, no big deal as it was always a quick fix. Yesterday on the other hand, there's no getting to stay on. I tried my usual routine, but nothing. I had my brother in law hold the wiper on the AFM clockwise, leaning out the mixture, and the car started and stayed running as long as he held it, once he let go, it would immediately run so rich, it floods out. I didn't have any time to trouble shoot. After spending a couple of hours on the side of the road tinkering with it, then waiting for a tow truck, my wife was not happy with me spending any more time trying to figure it out. Any ideas on this issue? Fixable, or is the AFM done for, and I need a new one? Bonus, here's a pic of my car getting loaded on a flat bed. Quickest $50 they ever made!

Thanks dude!