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L24 turbo conversion help needed

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So I've been searching a few forums and haven't found what I was looking for because threads all seem to get shot down to why not just 28et swap.

I currently own a 71 240z with the original l24 that's been built a bit by the previous owner(he died) so I don't know what has been done and it's been sitting since I've bought it(runs awesome though)

I live in Minneapolis Minnesota so I won't start working on her till we get into to 40-50s currently is -4 degrees

So I'll try to make my concerns as clear and on point as I can


is turbo mani I know my head is the e88 and the zxt mani will bolt on if I notch the head


I've been searching down rabbit holes and I think I want to go with megasquert diy kit with an msd and some kind of baffle in the gas tank with an external fuel pump and serge tank so it doesn't run lean when under heavy acceleration or hard steering.


will my pistons flat top) create to much compression with the e88 head and turbo setup to run reliably with about 10 psi of boost.

I guess I first need to determine what cr I have to say yes or no to but I guess what is a safe compression ratio to boost with should be the question.


My goal is a cheap reliable build to put out 220-260 hp and to be able to work on it by myself and with my nephews

My budget is now updated to work on chassis repair (floors and frame repair) and converting to efi first so it doesn't have to be out of commission this entire summer.

I expect to have my car done by next summer putting body work paint and interior off the list till September-October

My mechanical skills include watching my grandfather tune carbs doing oil changes when I have the time(I work 80-95 hours a week in the summer months) bleeding brake lines and changing gaskets on everything but the head

Edited by 240zdex

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Welcome to the forums.


First off I would give the forum rules a read just to get familiar, runs awesome is great, but it is not easy to get facts off of. Some numbers like good compression values would iterate the point more clearly in a factual manner that would make it easier to convince others that your engine is indeed awesomely running.


The reality is that an L28ET swap will be easier, cheaper, and more powerful in the end, but I don't mind bench racing once in a while. Is there a reason that you don't want to swap in an L28ET? Or is there a reason why you want to keep the L24? If it is just plain old boneitis then your fishing for having your cake and eating it too which is pretty daft.


First off we need a baseline, what do you have? What head and what block? What resources? What skill? What aptitude?


I am not sure what the exhaust ports have to do with the fuel rail not fitting. The L24 head INTAKE port probably doesn't have the injector reliefs to take the factory injectors.


If it is an E31 head the square ports will take an L28ET manifold from what I remember.


Your second category is glossing over a big thing, fuel is important, how do you plan on getting fuel to the motor, blow thru carb? Draw thru carb? FI connversion? Man with a spray bottle?


Spark management is also important, stand alone spark control? Aftermarket ECU? Fixed distributor? Man with a match?


High compression/flat pistons generally means you have to play with timing a bit more, run higher octane, and most likely you won't be able to run as large a PSI of booste. I want to say most of the combos keep this motor from being an interference motor so I don't think that is as big a concern.


You aren't really going to be finding any of these parts off the shelf, it is going to be on craigslist or ebay most likely, occasionally a junkyard or auto parts recycler.


Cheap and reliable don't go hand in hand here with the exception of the L28ET as that is fairly cheap and as it was an OEM offering so fairly reliable. The cheap way to do some things will just be a liability down the road, that doesn't mean you need gold plated exhaust studs or anything like that, but it does mean that gluing fittings onto the pan, running ebay parts, running bandaid setups will compromise reliability.


For example if you want cheap you would fix the distributor to one timing setting, but without the ability to control spark, you will be running the engine in un-ideal circumstances part of the time either on boost or off boost which leads to early wear if not outright failures. If you want cheap you would do a draw through turbo, but one hiccup on start up or backfire and you will be blowing out your intake as well as turbo and carb. 


With that in mind your budget is pretty light.


For a basic conversion, keeping the L24...

Turbo manifold


Oil feed line

Oil return line

Oil feed fitting

Oil return fitting

Block oil feed fitting

Block oil return fitting

Intake manifold

Throttle body



Fuel rail

Fuel pressure regulator

Fuel pump

Crank trigger wheel or dizzy

Down pipe


Intercooler piping

Intercooler piping joiners (silicone couplers)



A decent turbo is going to set you back about $600 off the shelf and the cheapest ECU that could run engine with some control will be a megasquirt and that would be about $400 (both those numbers are rounding down). That is half of your budget gone.


If you were going as cheap as possible you would be taking this stuff off of an L28ET, but once you take off all the parts you are going to be left with basically a stripped long block which wouldn't function anyways. Given how easy it is to pull the motor in our cars it would honestly be more effort to transfer everything over then it would be to transfer the block which is why people would recommend otherwise.


I would recommend you sit down and write out what you want and why.


Your overall budget is pretty decent, put a bit of money into the suspension and the interior and have a numbers matching driver would keep the most value and keep you entertained. I want to say Rome listened to forum advice and ended up with a pretty sweet turbocharged ride in that ball park.


Now if you were to say limited to that budget by some rule set like you had an actual guideline you had to follow, there are some interesting ways to boost an L24 on a dime and nickle budget, but without knowing your mechanical aptitude and skillset, I wouldn't be anywhere close to recommending you go down that road.

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Man! how awesome is that. Your first post and look at the reply you got!


I don't post very often but I have been in your place in the past. I had an L26 with a E88 head that I converted to fuel injection. You can drill and tap any head to fit a fuel injection manifold. If I were you I would first convert the block to fuel injection. Megasquirt is a good way to go if you can build it yourself. get comfortable with tuning and running on fuel injection. To got turbo after that is easy. This way you can also spread the costs a bit.


As a general rule you can say that a project like this will always cost you more that you anticipated. It's the little things that add up.


Turbo manifold $50

Tubocharger $300 (chinese ebay unit)

Oil feed line $ 25

Oil return line $25

Oil feed fitting $5

Oil return fitting $5

Block oil feed fitting $5 (1/8 T fitting)

Block oil return fitting $5

Intake manifold $100

Throttle body $50

Injectors $300

ECM (DIY Megasquirt base unit with mods for ignition) $250

Fuel rail $25 (stock unit)

Fuel pressure regulator $50

Fuel pump $100

Crank trigger wheel or dizzy $150

Down pipe $100

Intercooler $250

Intercooler piping $50

Intercooler piping joiners (silicone couplers) $75

Clamps $50


That's about $2000 right there


and I would like to add another $1000:


new fuel lines $50

laptop and tuning cable $250

2,5" exhaust $250

fuel filter $10

throttle cable setup $25

electric Fan $100 (stock fan doesn't fit with intercooler piping in place)

Wideband O2 sensor $150 (Tunerstudio's autotune is awesome)

full version of Tuner Studio $60

Jim Stim megasquirt stimulator $60


With a lot of searching you can probably reduce the price a little bit. But the money you save on deals you find will be swallowed up in all the unforeseen stuff.


I hope this does not discourage you. A S30 with a turbo is pretty awesome beast and totally worth the effort. Good luck and keep us posted :D

Edited by Xander

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Thanks Seattle jester and Xander yes it's my first post here and I don't have very much information on my car because I bought it and only drove it around the block and on my trailer.

My skills are vary basic oil change brakes tune ups no welding skills whatsoever but that's what this cars for to me I guess

That said I do appreciate your guys information and I plan on doing it but it may just take a bit more time then I thought but what build doesn't

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Based on your skill level your budget is low , but don't let that stop you. Read until your eyes hurt and make good use of your budget. Don't shoot for HP goals - shoot for smaller goals like making your fuel system good enough for FI . Even with the "easy" zxt swap- there's a lot of ground to cover

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Look at that Xander filled out the list for you!


Keep that in mind though saving money by buying an Ebay turbo or knock off turbo affects your reliability, they seem to be making them more and more genuine, but overall consensus is that they won't last more then 10,000 miles if they don't break within the first 100-1000 miles.


The basic Megasquirt kit can indeed be had for that much, but that does require quite a bit of soldering, and that is quite a bit of precision soldering at that.


I would definitely give the car a once over before you start planning your build. Having to pay someone to replace the floors or frame rails is going to suck up about 1/4 of your total budget if not more very easily. 


If your skills are basic keep that in mind. Write it on a banner and hang it. Use that knowledge to your advantage. Realize you won't remember how things came apart, or where things are supposed to go. Label everything, document everything, take pictures of everything.


Do your own research and read a lot. There is so very much on this forum alone, and you can find different flavors on other forums like classicz, vicz, atlanticz etc.

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