Engine Controls for a N/A '77 280z Converted to Turbo?

[nienberg.11]

I'm planning on doing a bolt-on turbo conversion to the stock engine in my '77 280z. I have the turbo, downpipe, manifold, and injectors from an '83 280zxt, and I mostly have this whole project figured out, with one exception. I have no idea how I should go about maintaining the correct fuel/air ratio. I have to complete the whole conversion in the week I have off for spring break, so messing with Megasquirt isn't an option. I've been told by one guy that I should just leave my stock ecu and afm intact, and simply adjust the tension inside the afm to account for the bigger injectors, and other people have told me to buy a device to change the signal coming from the afm. Another problem I'm faced with is that I don't know if the 280zxt injectors will support the kind of boost levels I'm shooting for (10-12psi) without a rising rate fuel pressure regulator or some other modification. If anyone has any insight on this situation, I'm all ears.

-Mike

[proxlamus©]

LoL... this is so weird...

 

I have a 1978 280Z N/A that I will be bolting a turbo onto over SPRING BREAK! haha Small world huh??

 

Anyway... you can run the N/A AFM and the N/A ECU and run about 10psi *INTERCOOLED* and at least 91 octane.. or you will detonate BAD...

 

You can change the air/fuel ratio with something called an Apexi S-AFC...

basically it's a Super - Air flow converter....

 

what this small computer does is intercepts the AFM signal, "tricks" the ECU that more air is in the system, so it puts out more fuel. There is a low throttle setting and a high throttle setting.

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The second-generation S-AFC is a fuel computer that adjusts fuel/air ratio by modifying the air-flow meter/MAP sensor signal. The S-AFC features a user-definable, eight-point, adjustable fuel curve that can be set in 500 RPM increments. The range of fuel adjustment is +/- 50% at each of the user-defined setting points. On hot-wire vehicles, the Deceleration Air Flow Correction function is capable of curing the erratic idle and stall problems associated with open-atmosphere blow-off valves on hot-wire air-flow meter systems. The S-AFC is capable of monitoring and replaying the following data channels in Numerical, Analog Meter and Graph displays: Intake Manifold Vacuum/Boost Pressure, Air Flow Capacity, Intake Manifold Pressure, Karmann Frequency, Engine RPM, Throttle Position, and Air Flow Correction %.

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It needs a tach input though.. and the stock tach sender won't work, so an MSD tach signal converter will make it work.. or an MSD 6A ignition with tach signal with run fine.

Also you need an 60mm TB from a 240SX.. and use the TPS throttle positioning sensor from the 60mm TB .. because our's won't work.

 

Now to increase fuel by it's self... you can either choose a Adjustable Fuel Pressure Regulator... or an FMU (Rising Fuel pressure regulator)

I posted a thread over on Zcar.com.. i suggest reading it...

http://www.zcar.com/forums/read.php?f=1&i=547505&t=547505

 

Very very informative thread...

 

BTW what are you doing for the oil pan? Are you running an N/A pan with a welded bung? or an turbo oil pan? If you run a turbo oil pan, you will need an turbo oil pickup since the N/A pickup won't work with an turbo pickup

[nienberg.11]

Thanks for all the info Prox, I've read some of your posts before, and it looks like you and I are in a pretty small crowd of people converting the n/a l28's to turbo. Also, I just looked at your cardomain page, and we must have a lot of the same ideas...I'm planning on replacing my p.o.s clock with my boost guage too, just put it in the casing that holds clock. It's for the best since I've gone through 3 clocks in a year for that car. Anyways, I'm going to keep my n/a oil pan, and tap some threads into it for a threaded bung that I got along with my 280zxt parts. The guy who sold me the zxt parts made it up, it's basically a piece of threaded pipe with a nut welded onto one end. I read the your thread, and it did make things clearer, but I was wondering, do you have any idea if the zxt fuel pump would be sufficient if i was to run it with a rrfpr and my zxt injectors?

[proxlamus©]

How much boost are you planning on running??

The Turbo fuel pump will supply enough fuel for about 12 psi of boost.. roughly.. before it starts to lean out...

You will need about 80psi of fuel for 10 pounds of boost.

 

but.. with an N/A block and head.. your compression will be a bit high... so unless you have 93 octane... and ZXT injectors you will have detonation and pinging...

 

BTW - RRFPR are the same as FMU's (fuel management unit) but it should be plenty.

 

Here's an e-mail I got from a very nice gentleman Dan...

----------------------------

I would recommend finding a P90 head. You will have detonation problems with the N47 over 6 psi of boost.

 

The fuel pump system is very important when using a FMU. I have been fine tuning my setup over the past year. I found it is best to use a Mallory comp110 low pressure pump to feed two stock type efi pumps in parallel. Here is a photo of my twin pump setup. Of course there is a Mallory low pressure pump by the gas tank feeding the two efi pumps in the engine compartment. I relocated the fuseable links to under the mounting plate and used a relay to power the pumps. I cut off the wire from the fuseable link connectors and used fuseable link wire and crimp connectors to complete the circuit.

 

I’m using msd pumps which cost about 100.00 each. I run about 90 psi for 12 psi of boost and 100 psi for 14 to 15 psi on the NA stock injectors. 60 psi is good for 6-8 psi of boost with NA injectors.

 

I’m using the stock FPR and a bell engineering fmu and stock NA efi computer.

 

I disassembled the distributor and welded the advance slot in the so that I get only 8 degrees of advance. I set the timing to 20 initial (28 total) and use the vacuum advance. The vacuum advance is great for gas mileage because it adds 10 to 15 degrees during no boost conditions.

 

I use 93 octane but can get by with 91 if I retard the initial timing 3 degrees.

 

I liked the straight T3 turbo better than the t3/t4 for street performance. The t3 made 5 psi of boost by 2200 rpm and full boost by 2800 rpm! The t3/t4 only makes 5 psi at 3000 and full boost by 3500. The low rpm torque of the t3 was great and fun to drive! Rolling on the throttle in low rpms in 3rd gear and getting wheel spin is fun.

 

I’m using the t3/t04b-h3 wheel turbo. The t04b turbo doesn’t require a spacer like the t04e.

 

No need for a IC if you are running less than 10 psi of boost. I know the dynos show big improvements with an IC but it is not that apparent in the “pant seat dynoâ€.

 

You will need a 2+2 clutch (240mm)! The stock clutch will hold 10 psi of boost. After that you will need a spec stage 2. The spec stage 3 sucks on the street but is very tough.

 

This system works for me but the cost of the three pumps (370.00) and the fmu (200.00) is about the cost of a “stand alone†efi system.

 

You need a fuel and boost pressure gage in order to tune correctly. I put a boost gage in the clock location and a fuel pressure gage on the pillar.

 

Walbro pumps are loud! Your whole entire car will vibrate!

 

My g-tech says my 78 280 NA car is making 130 hp, so we are close. But the turbo car is doubling that at 15 psi!

 

Use the formula (boost+14.7)/14.7 to get the hp multiplier form a turbo. So 10 psi would give you: (10+14.7)/14.7=1.68,

1.68 x 135hp (you current NA hp) = 226 hp.

 

I would just do a simple turbo install first then do the IC later.

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That might help you out a bit

[TheSkrich]

Since nobody else has said it. Welcome to the board.

 

Hmmm.. The metropalis of McComb i think Ive seen you cruising around one of the suburbs before...... bahahaaaa

 

Cornflabbed Nemeyer and his go devil {Shaking fist in air} inside joke

[nienberg.11]

Lol Skrich, i might have seen you around mccomb too. The guy with the trenchcoat who goes around spraying the destitute and small children with hot sauce from his windsheild washers right? That'll take em down a peg lol.

Anyways, prox, I plan on running 10-12 psi of boost, intercooled, with the zxt injectors. I was under the impression that the stock '77 engine had n/a dished pistons, which are only different from the turbo pistons because they have weaker ring lands. I was also under the impression that this gave me a compression ratio 0f 7.5, which is favorable for turbo applications. I think i'm going to run an fmu, and either the zxt fuel pump or some aftermarket fuel pump. In any case, I'm not going to run 3 separate pumps. I'm on a budget for one, and that just seems impractical. Keep me posted on how things go with your project.

[proxlamus©]

ok since I have done the swap..

 

i would advice.. DONT run on N/A electronics..

 

several people have.. but with a turbo.. im not sure of reliability and power..

 

for under $250 you can go megasquirt.. and tune it all ya want..

 

my car ran like crap on N/A electronics.. never again

[Guest Loose_Screws]

I ran stock FMU, no IC, and 8psi on a converted N/A L28, but it ran like crap. I added P90 head, electric fan, large IC, 440cc injectors, and megasquirt in one swipe. Talk about waking that L28 up! This is when I discovered the stock clutch problem and whenever I would start getting into boost good, the clutch would let go!

[Guest bastaad525]

Agreed, if you can avoid it, do NOT run the N/A electronics. Used turbo electronics can be had cheap. If you can't find them I have a guy who can get them for you, PM me. Even the dishtop N/A motor had a little more comrpession than the turbo motor because of the different head on it, not much though I think it's like 8:1 or 8.5:1 at most. With the higher compression, I don't know how much boost you're safely going to get away with on stock injectors and turbo efi, even with upping the fuel pressure. 12 psi is probably at the edge of safe w/o some upgrades.

 

If you run a boost timing retard device you can get away with more, but stock ecu doesn't pull out enough timing (the timing retard device is NOT an option if you go with N/A electronics).

 

I run an RRFPR on my car, all stock turbo motor, EFI and stock injectors, running 13-14psi and making approximately 240rwhp/300ftlbs of torque. At full boost/wide open throttle, I have the RRFPR set to run 70psi of fuel pressure, and it runs pretty rich. I have the BEGI RRFPR and it's a great unit, easy to install, easy to adjust. You can get 370cc injectors for cheaper though ($200 for the RRFPR, used 370's about $50-100 for set of six). I didn't go for larger injectors as I didn't want the tuning hassles of getting it running right OFF boost... RRFPR doesn't affect the car off boost.

 

I'm running an MSD fuel pump which was pretty cheap, less than the Walbro most guys go with. The stock fuel pump took me up to about 10psi before it started to lean out on top, though some have run them at higher boost, I think mine was pretty tired.

[Kazuya1274]

This thread makes me remenisce when I first turbo'd my Z. I used the stock engine w/p79 head. Something about it, which I can only think of the compression being the culprit, but I had some severe traction problems with that engine. I don't know if it was the tuning or the engine gods decided to take it away, but the engine started smoking from the pcv and it finally let go at the 1/4 mile track, after running a crappy 60ft time of all wheelspin. I then swapped to the turbo engine, and the low end difference took away that bottom end lethalness, but it actually made the car easier to manage and take off from a standstill. I continued to use the stock NA electronics, and compensated by turning the screw on the AFM and using a RRFPR. My turbo block never had an issue with the rings, but it sure did like to blow the Fel-pro head gaskets. But, it can be done on the NA electronics. It may not be the best way, but it can work.

[mc]

....i turboed the v6 in my 1988 200sxSE and have no problems using the n/a electronics...granted its a remote turbo[rear] mount location and not as efficient as a engine mounted set up....but it works fine...idles smooth as glass,no fast idle stall outs,great gas milage and hits 5 hg boost.

[Tony D]

5 hg boost?

 

Dude, that's 2.5 psig...

 

Is that a typo, or what?

 

Fuel management is critical, blocing headgasketsand breakingrings is DETONATION and is the culprit of either to little fuel, or too much spark advance at a point on the curve. Or both.

 

A turbo's fuel requirements are almost independent of rpm! It is a varaible flow engine, so unless you have a non-linear AFM that meters above 3500 when theturbo is kicking in, you can not properly manage the fuel delivery needs of the engine!

 

A RRFPR is basically turning your EFI into a BAD carburettor. For that effort, buy triple solexes, build a surge box, and be prepared for FAR MORE power than you will get using stock N/A electronics on that turbo!

 

In the end, with the advent of the Megasquirt, there really is no reason to screw around with stock electronics whatsoever. The cost of the RRFPR and the time you spend trimming it will not get you the results you will get with the Megasquirt and some basic tuning of the fuel maps.

[SleeperZ]

Tony, I'm sure he meant 5 bar boost.

[Kazuya1274]

I agree Tony D, programmable F.I. is the way to go. I just already had everything setup before I ever heard about Megasquirt, and SDS was a little too expensive. I still think my original NA engine was out the door before it ever had a turbo on it, I kinda just "forgot" about that overheating problem it had while the car was down! Anyways, I'll do it again sometime, now that I've had the experience before, I know what to do a lot better now. 70 through 75 only this time, prefereably 70-73! I'll be looking for one when I move to Torrance later this year.

[Tony D]

Torrance, eh...

 

That's less than an unreasonable distance from my place.... LOL

 

Ask 1 Fast Z how the Megasquirt hacks into a stock EFI harness. I figure I could probably do the conversion in 2-3 hours using the stock stuff if I put my head to it.

 

But for the effort, I would simply make another harness, and go from there. It's not that hard, and easily done in a day (or a week after work sitting at the plywood building board laying out wires and terminations.)

 

BTW, Some have been using Megasquirt for over three years now. Some of the original group buy cars are another year beyond that! The latest push in recognition of that system has been because of some press it has gotten in the General Automotive Magazine Arena. Before that, it was just internet geeks and programmers that knew about it! LOL

 

In actuality, you can purchase all the components for the Megasquirt for about $65 when it all comes down to it...

 

The E-Bay assembled kits just make the project faster by about 5 hours of assembly time, and whatever time it took to source the stuff on your own.

 

What I'm getting at is it's still not too late to convert!

[proxlamus©]

I used the STOCK N/A harness on my car.. and with the help of my FSM and Blue's tech tips page... anyone can use the stock harness..

[Guest bastaad525]

you guys still knocking the RRFPR? look, the thing works, yes it's a bit pricey for what it does compared to some other options for that cost, but it's SO easy to install, and tuning it took me four pulls on the dyno with a WB O2. It's not the most efficient way of getting the fuel you need but it WORKS.

 

Just because Megasquirt is cheap don't mean it's easy. Tony you yourself have had NUMEROUS headaches getting MS installed and running. MS has it's own forum for that very reason... yeah it's relatively cheap but it's a complicated system. Maybe tuning it isn't so much but getting it in and running has proven to be a headache for many! Anyone in doubt of this fact need just mosey over to the MS board and see how many threads there are of people having install issues.

 

Having dynoed my own setup before and after the RRFPR, I say it performs VERY well. It literally just augments the stock EFI's fuel curve. I cannot stress this enough. Now the only problem THERE is, the stock EFI's fuel curve isn't too optimal to begin with. Anyone who's dynoed on stock EFI knows that it likes to run very rich in the 3000-4000rpm range, and then lean back out from that point on. And yet, lots of guys are completely happy with how the stock EFI runs... well the RRFPR wont change that, it will just let you turn up the wick a little bit!

 

At any rate, I overlayed my dyno results at 13psi with the RRFPR over my results at 10psi w/o it, and the fuel curves were practically IDENTICAL. Rich midrange in the 10:1 a/f ratio range from 3000-4000rpm, right when you need it since that's when torque and cylinder pressures peak, and then up in the 11-12:1 air/fuel ratio area from 4k to redline. This is with only upping fuel pressure about 17psi to a total of 70psi at WOT/full boost (stock FPR would give 53ish psi). My 260cc injectors are now effectively flowing the equivalent of 320cc injectors and keeping me at a nice safe a/f ratio at 13psi of intercooled boost. Keep in mind I"m running even LEANER at 13psi than I was when I dynoed at 10 because at 10 I didn't have an I/C either. So the RRFPR is providing even more fuel than the initial a/f numbers suggest.

 

The greatest thing about it though that I"ve said before and will say again and again is the RRFPR has NO effect on off boost or even light boost driving conditions. So no need to tweak your AFM or any of that, let alone reprogram whole fuel and timing maps on MS or other standalones. I only had to tune the RRFPR for on boost conditions, which was easy, one setting screw to adjust and that's it.

 

While testing, I found that the RRFPR doesn't even start to effect fuel pressure until about 5psi of boost is reached, so it doesn't really 'overlap' the stock EFI's enrichment up to 7psi of boost by very much at all. I know SleeperZ has mentioned this in the past as one of his big concerns with running one. Again, I found on the dyno that it ran NO richer at 13psi with the RRFPR than when I dynoed 10psi with stock everything.

 

Another big benefit that I found in a magazine I was reading... it was the April '05 issue of Dsport magazine, which is one of the last respectable import magazines left IMO... they always write very technical, informative articles and seem to know their stuff, and refrain from the immaturity found in most of today's import mags.

 

They found that as you upped fuel pressure, the injectors' spray patterns got BETTER and BETTER. And they did NOT encounter an increase in inconsistency in the amount of fuel delivered over a period of time, as some have claimed, but rather they actually ran MORE consistently, putting out closer to the same amount of cc's. The spray become more and more atomized, up until about 80psi, which they said they found to be the optimal pressure. And you all know the benefits of the fuel atomizing better. The injectors didn't start having problems until above 100psi, and didn't actually 'lock' until some really high number, I forget but I think it was 120psi +.

 

Really, I think the ONLY negative going against the RRFPR is it's high cost compared to other solutions. But even now I feel the cost was justified due to how easy it was to install and tune. I'd rather have less money than more headaches! I've been running the thing for quite a while now and have had NO problems with it, and would highly recommend it to anyone who doesn't mind the initial high cost. This is about as easy as it gets for additional fuel and boost!

[Tony D]

"Tony you yourself have had NUMEROUS headaches getting MS installed and running. MS has it's own forum for that very reason... yeah it's relatively cheap but it's a complicated system."

That really is not a fair comparison Bastaad. i was the first to use the system in MY application. Had I chosen to go the route Moby took, suing an 82/83 setup, it is a plug-n-play setup, no harder than any other system.

I was actually running within 15 mintues of starting the system when you look at it.

 

But having gone the route of the RRFPR, and Stock N/A electronics, I would NEVER do it again!

Same can be said for going with a blow-through triple carburetion system.

 

The difference between my comments and many here saying the MS is "hard" and holding my case out as an example is that GIVEN THE PATH I TOOK, I would STILL recommend the MS setup over ANY tweaking of the stock system.

 

Until you have actually HAD an adjustable fuel and spark delivery system on the car, and GOTTEN RID of the NUMEROUS HEADACHES common in "tweaked" setups, you can't begin to understand why we make the suggestions we do!

 

I would NEVER consider tweaking stock electronics now that MS is Viable, and TESTED with CLEAR instructions for the install.

 

And the reason MS has a forum here is to HELP the ininitiated SHARE our EXPERIENCE. Withthe commonality of questions about Tec2, Tec3, and SDS programming, should we all draw the conclusion they are also a "pain" to install?

 

It's all relative. MY case is unique because I may be gone for MONTHS at a time, with only a few hours or a couple of DAYS to work on my project. IN TOTAL my time expended on a never been attempted developmental workup on the MS really has been FAR less than the travails you have gone through screwing and tweaking the stock system! The difference between your work, and mine, is that you have been at it continually for three years (+?), whilst I have spent maybe a month time in total in three years working on my project---with a result that I can now go 0-4500 in fourth gear and back to 0 in WELL under 3/8 of a mile... With not much more time on the road than that. It runs well, and had I used the system everyone else used, it would have been up and running FAR sooner.

 

But then that group of people out there with 81ZXT's or 81ZXT-Based Engine swaps would never know what they needed to do to make the system work with the MSS setup.

 

So don't use my experiences of doing a first-time install. Even with ALL the problems I have had (95% of those BASED IN MY LAPTOP, and NOT the MS!) I would STILL recommend MS over tweaking a stock system.

 

For the cost, and the benefits, there really is no comparison!

[proxlamus©]

yep... i bought my assembled MegaSquirt for under $250 and it took one to day to install thanks to Mobythevan, the greatest guy ever!! haha..

 

But anyway.. it took me nearly 1 week to attempt to get my N/A turbo setup running right.. took less than a day to get MSnS up and running and perfection right out of the box!!

[Guest bastaad525]

Tony - heheh I knew you'd say that. In retrospect, it wasn't good for me to use you as an example... I knew you had 'strayed from the beaten path' with your setup... And I do recall reading some of your posts where you found your laptop was causing you all kinds of problems. So your problems would not be representative of what most guys could expect doing an MS. So for anyone who read my post, strike that comment from the record.

 

But, there is still the fact that it seems quite a few other guys have had problems getting their MS's running. Now, I'm not really trying to say MS is really so difficult... like you said, it's all pretty relative. I'm sure that as far as standalones go, MS is probably one of the easiest ones to use on an L28ET (of course I really have no way to know that for sure as I've never used any of them, but I've read enough to determine that SDS, Tec and others do seem very complicated), and definatley the cheapest. But I'm saying, compared to installing and tuning an RRFPR (install took me about 30 mins, and it was tuned in less than an hour after a few dyno pulls), it's a much more complicated thing. Also, remember I'm using my RRPFR with stock TURBO electronics... as opposed to you using N/A stuff.... I myself would strongly advise against anyone using N/A electronics in ANY way with a turboed motor.

 

Look I'm definatley not trying to put MS down... I know it is a good system and for the price is really amazing what you can do with it. I'm not even gonna TRY to be so silly as to say the RRFPR is 'better'. I'm just trying to defend the RRFPR, because in my case, it really has been great. Again, it was SO easy to install and tune, and I honestly have no complaints about the way it's worked for me these last months. As far as I'm concerned, my car runs great, when driven normally or driven hard. Could it run better? Probably. Could it run better with MS? Most definately. But with my shortage of time and money, it was a great solution for me and it works FINE IMO.

 

Honestly, the ONLY complaint I have about the way my car runs now has nothing to do with the FPR... rather, it's the even cheaper/easier solution of a boost controller I'm using. I HATE that my boost spikes the way it does... you can FEEL it when you get on the throttle and it surges and then suddenly drops a little bit as the boost spikes to 15psi then settles down to 13. I REALLY want a better boost controller.

 

Tony, I'm confused, when you say I've spent so much time tracking down problems and tweaking my stock system... I'm not really sure what you're talking about. For one, I've only had the turbo swap for two years And yes, I've had TONS of problems with my car after the turbo swap, but most of them have been MECHANICAL problems, not problems with my EFI. I've had a few bugs, sure, but I don't think I've had any more than anyone else who's done a swap with stock EFI... little things like corroded wires needing cleaning. Nothing major, and I haven't spent much time really messing with the EFI. And I've had NO EFI related problems in a LONG time. I have however spent hours and hours fixing mechanical problems... but they were nothing the MS would have fixed

 

It just seems to me that you guys paint this bad picture of how the RRFPR works and how it will make your car run, and for a while a couple of you had me convinced against getting it, but then I talked to a couple guys who were using it and loved it and took the risk to try it myself and have not been dissapointed. It has given me NO problems whatsoever.

 

In my case MS would have been somewhat costly. I have the '81 front mount CAS and 'blank' dizzy, for one, which I thought I'd need to change out to use MS, but apparently you found a way around this?? Also, if I weren't using the RRFPR for extra fuel, I'd obviously have to switch up to larger injectors. Then needing a lap top. Then a proper dyno tune OR a WB O2 to tune it myself. I don't remember what else but I remember pricing everything I'd need maybe a year ago and coming up with like $500+. So the RRFPR was economically much more feasible to me.

 

On top of that, I'm very scared of trying to install the MS myself. I have horrible luck, and I just know that there's no way I'd get the MS in w/o problems. And I don't feel like having it undrivable while I spend lord-knows-how-much time trying to iron out a whole new set of bugs. It's running good now and I just dont want to fuss with it anymore, but rather just enjoy driving it. However, if I had someone close by to me like Moby who could help me get it in in a days time and who knew what they were doing, I'd probably have installed MS long ago Make no mistake, I would LOVE to have a programmable standalone system instead of just the RRFPR.

 

Tony... you live somewhat locally no? heheh but... I'm gonna guess that you are much too busy... if you hardly have the time to work on your own Z. Do you think if ever the day came I could get everything together that I'd need to install MS (this would NOT be any time soon trust me) you might be able to help me out on a few things? Mostly, on how you modified the crank pulley so I'd be able to use my '81 CAS.

 

At any rate... for people who want a simple, working solution to getting extra fuel the RRFPR is great, again the only negative really being it is kind of overpriced for what it is, but it works. And it works well.