How use stock ecu?

[Guest Anonymous]

I haven't posted for a while. I've been busy and not doing much on the Z. To recap, I have a 1971 240Z with an L28T motor. It is currently setup with dual downdraft Webers with t3/t4 hybrid turbo, handbuilt exhaust manifold, manual boost control, no intercooler, blowthrough system. No means currently to retard ignition under boost. Engine makes lots of power but heats up quickly and detonates if run at anything >8 psi for extended periods.

 

I've looked at a variety of options - from soup to nuts:

1) monkey with current setup - add O2 sensor and mixture guage on dash, MSD box for ignition control, plus intercooler and water injection. This would probably make my current blowthrough setup better and less volatile. Pretty cheap and easy.

2) do a v8 conversion

3) take off the carbed setup and pick up a stock 280zt exhaust and intake manifold, stock ecu, stock injectors, etc. Easy???

4) ditch the turbo altogether and just run the turbo engine n/a with carbs (this would work but not great d/t lowered comp ratio, turbo cam). Easy but not satisfying.

5) go aftermarket sds etc.

 

At this point I want the easiest and cheapest way to get my car back on the road but still have reasonable performance. I don't want to spend the money on SDS right now.

So here's my question:

 

I think my easiest and cheapest (minimal fabrication)option is to pick up a 280zt intake, injectors, exhaust manifold, distributor, stock wiring harness and computer from 81-83 280zxt. I will need also I think the stock knock sensor, electronic ignition trigger (on crank balancer for 81 I understand), air temp sensor, etc etc.

 

If necessary I will stick with all stock stuff - I just wanna get the car back on the road and make it safe! But if possible I would like to use the T3/T4 turbo I have. I would also like to use the wategate and adjustable boost control I have. I'd also like to improve things a little with an intercooler - probably a Supra intercooler or something off ebay. I've also heard you can use a 60 mm throttle body form a 240sx and injectors from a mustang/300zx/2nd gen n/a RX7.

 

Any helpful comments from people? Where can I find the best info on tweaking a stock ecu controlled 280zt? How hard is it to adapt a t3/t4 hybrid turbo to the stock exhaust manifold? Will I just get into trouble doing this? Is it difficult to adapt an aftermarket wastegate and adjustable boost control to stock setup? Is it hard to add an intercooler? Does going to larger injectors make you run chronically rich as the computer isn't set up for this? Lots of questions; I've tried doing a search at zcar.com but looked through a couple of months listings without really nailing down answers. Thanks, guys. Remember, I wanna fix it cheap and get it back on the road. If I need to do everything stock to start with I will.

[Guest scca]

buying a "complete" ZXT% setup isnt cheap,

cheaper than SDS but not my definition of cheap anyway-----

it will cost at least $500 Canuk bucks for the whole setup. better to put that $$ towards a SDS ...IMO.

 

rough pricing

AFM $75-100 NOTE all pricing USD

computer $50-75

wiring harness $150

injectors and intake and exhaust $100

 

oh and 82-3 needs a different distributor and the 81 needs a crank angle sensor too..

plus all the sensors on teh engine itself, HEAD temp, water, etc. etc.....

and thats IF you get it to run PERFECT with the stock ZXT stuff..

[Drax240z]

A t3/t04 should bolt to the stock zxt exhaust manifold, as it uses a t3 exhaust flange.

 

As for the additions, it depends on your fabrication skills. An external wastegate or an intercooler would probably be about the same amount of work, requiring some new piping, etc.

 

Personally I wouldn't screw around with the stock system/wiring/sensors. I'm using stock injectors with a few other cheap mods and an SDS. I'd say the whole setup could be copied for around $1500canadian. (SDS, fuel pump, injectors, etc... my whole engine was $300 from a wreckers) Like Mike said, throwing $500 or more at the stock system might make sense at first, but I think once you really get into it you'll enjoy the fact that you can tune the car easily for any mod you want to make.

[scottyMIz]

I agree i have the stock system and if i could do it again would of gotten an after market one.Hey drax what did the sds cost?I'm looking at changing it all out igniton and efi.

[Guest scca]

i was offering SDS for a discount to hybridz'ers -- and a few dimers and a mustang conversion..

 

oh and to answer grahams questions i missed..

1) to get it reliable CHEAP bolt on SU's

 

2) run SDS

 

3) go V8. chevy is easier than 5L but both can be done ...

 

skip the other 2 choices.

 

[ August 20, 2001: Message edited by: scca ]

[Brad-ManQ45]

If I lived in the mountains, or high desert like I did in El Paso, the turbo could be a lot of fun - easy to stomp V-8's.

 

If you only want what the stock injectors can do for you just get the '83 Turbo setup w/your hybrid turbo and an intercooler - although that will really start taxing the stock injectors if you run more than 10-12 lbs of boost. You can get a few more hamsters by adding a rising rate fuel pressure regulator, but don't expect miracles here. You're not able to go up in injector size w/o computer change.

 

If you want more:

 

DO NOT - I will repeat DO NOT get the modified 300ZX unit - tuning difficulties will abound.

 

Go SDS and pat yourself on the back.

 

If you like low end torque and hate the rubber-band acceleration of a small turbo motor, go the V-8.

 

I have an '83 Turbo with stock injectors pretty well maxed, and a '75 that I'm going to put a V-8 in.

 

Since I live in Atlanta now I will use the turbo to go to the mountains and the V-8 for fun around town!

[Guest Anonymous]

All excellent answers guys - thanks for the input. I'll look again at the cost of SDS - maybe it is in the budget right now - but I think probably not. I appreciate your wisdom but I think right now I gotta do what I gotta do. I've found an 82 turbo 90 minutes from here and they will give me everything I need for $400 Canadian plus tax. Since I need the manifolds anyway even if I go with SDS in the future (If I used my handbuilt exheaust header I'd have to fabricate an intake manifold due to fit problems)I think I'll go for it. I'm gonna take lots of pictures and make sure I get all the sensors, etc. that I need. I will sell my Webers to offset the cost, incorporate my t3/to4 and adjustable wastegate, put on a mixture meter and get the thing going. Will likely do the intercooler later.I'd appreciate again any more input as to how to make the stock ecu work to the max allowable by the stock injectors (I've heard you can get about 230 hp out of the stock injectors). Thanks again.

[Scottie-GNZ]

quote

If you like low end torque and hate the rubber-band acceleration of a small turbo motor, go the V-8

 

Brad-ManQ45, I am curious to know exactly what you mean by that statement, what is your definition of small and what small turbo motor motor have you driven that gave that effect?

[Drax240z]

Went for a drive in an Audi S4 last week. It was scary fast. Gobs of power anywhere from 1500rpm to redline. Not a hint of lag. Not bad from a small 2.7L twin turbo.

 

Its amazing how may misconceptions about turbo engines still float around, my guess is that they are from people that did the early experiments with a draw through system, which is decidedly very primative as turbo's go. A properly setup turbo system can have no noticable lag, and produce gobs of torque even at low RPMs while still maintaining high rpm performance.

[pparaska]

Drax, Scottie, I think I know why I HAD the misconception that many trubo cars had a "rubberband" acceleration character:

 

I HAVE (HAD) ONE!

 

92 Mitsu Eclipse (2 liter turbo)

 

The car weighs a bit over 3100 lbs

 

The stock system has a bleeder tha ALWAYS bleeds some metered boost pressure/volume to the wastegate canister. This is unfortunate, as it causes alot of "around town" boost lag. I corrected that with a relief type manual boost controller that bleeds metered pressure/volume to the wastegate canister only after a set pressure point. This helps tremendously on the around down and high cruise in 5th scenarios! It's still laggy below say 3000 rpm though.

 

But this is an old design. It seems from my reading that the newer OE cars have less lag.

 

And a custom built setup if done right (for low lag design) won't have much at all. That type of system may give up at higher rpm, and heat the intake air too much at high rpms (since the turbo would be sized for lower rpm performance). Of course, two smaller turbos may help this too.

 

But it's a function of cubes as well.

 

I USED to think that all turbo cars had lag, due to my reading mags for twenty some years, etc. and having owned one that was laggy. But I've learned that this doesn't have to be so.

[DavyZ]

Ditto on what Pete said--having owned an older turbocharged car, lag abounded. When I went to work for VW, their turbocharged cars had little to no lag, BUT there was still a kick-in-the-pants difference between the turbo 1.8L and the n/a 2.8L--probably due in most part to cubic inches. Funny thing is that with merely a chip change, the diminutive 1.8L puts out more horsepower than the 2.8L. Ahhh, nothing like ECM tunability for turbos!

 

Hmmm, maybe I'll turbocharge the V8 sometime...Lonehdrider, are you listening? I may need your help...

 

Davy

[Brad-ManQ45]

I have had three turbo cars - an '85 Conquest (Starion) that I had the HKS intercooler setup on running 14 lbs boost, and '87 Starion ESIR that I bumped the boost up on, and my '83 280ZX Turbo.

 

In normal around-town driving, unless you stay close to 2600 - 2800 rpm in the ZX, when you first floor it, it takes a few momentos to get up and go. Thisis after reducing lag with 3" mandrel exhaust & cat, and T3/T4 Turbo. (Assuming you're NOT in 1st gear).

 

I am a fan of instant torque - the better to squirt through traffic. No problem, but just no as responsive - and you can NEVER eliminate ALL of the lag.

 

The Mitsubishi products had MUCH more low end torque (2600cc 4 banger) than the 2800cc 6, so didn't notice it as much.

 

If I were ever to rebuild the ZX engine I'd put in 9 to 1 pistons and a new FI setup and intercooler and probably never complain again, but I've always wanted a V8Z so I'm gonna do that first.

[Guest Anonymous]

I hear ya Davy, maybe make us two turbo setups ..

 

Regards,

 

Lone

[BLKMGK]

Please make that three if it works out. I'm always up for more power and turbos rock! May go ATI down the road but hey a turbo is pretty neat and quiet.

[Kevin Shasteen]

Regarding the "Rubberband" effect on turbo's; no actual hands on experience here- simply recent "Book Learning".

 

After reading 1/2 way thru Corky Bell's book of which he makes a hole heap of interesting points I've grown to understand the misconception on Turbo's.

 

For starters most people (up to recent-including myself) dont understand turbo's & how they work. Most RPO Mfg's Turbo cars are going to be produced w/all kinds of limiting factors, for warranty purposes, therefore-the car is going to be a compromise in just about all circumstances.

 

I've not had actual turbo experience but I did work the warranty side of GM for 5 years (the GN & GNx hay days) & the mfg's come down hard on the dealers about replacing turbo's under warranty....a lot of scrutiny abounds.

 

I remember taking one claim where the dealer was "Tattling" on the customer; claiming he witnessed the customer at the local 1/4 mile track hot rodding his GN & smoking his tires on his burn out to rediculous levels. The dealer claimed this equated to "Customer Abuse". I told the dealer I understood his concerns but if GM didnt want their cust's hot rodding the car they shouldnt put a turbo in it & packag the car as a muscle car; I definately auth the new turbo (I hate hypocritical thinking).

 

Remember, the "Lag" is not a bad thing; its merely the time one waits for Boost to build. Therefore, in order to reduce "Lag" time, one must understand all the dynamics with which "Lag" is created; as in Pete's alteration of the Wastegate set up.

 

Lag is nothing more than the effects of controlling "Airflow" by way of controlling Boost...or the bleeding off of Boost.

 

According to Corky Bell if you want a low boost threshold (lowest rpm where boost is created) then usually you will lose boost at a higher rpm but at a lower rpm than usual had you not altered its initial set up; if that makes sense-providing I expressed that point correctly.

 

Its similar to the ole "Gobbs of Power" at low rpms at the sacrifice of "Top End Power"...everything's a juggling act. Corky claims when you are researching a turbo to find one whose Turbo allows 65/70% efficiency beginning at 3/4 WOT. Anything sooner sacrifices tope end boost.

 

Corky Bell does compliment the Porsche 944, Buick GN/GNX & the Lotus Esprit turbo set ups as quality Mfg's powerplants; he says most all other factory systems are wrought w/comprimises; as with any compromised system-the Hot Rodder must understand its dynamics so they can then modify the short comings for positive gains.

 

Kevin,

(Yea,Still a, Turbo Learning, Inliner)

[pparaska]

Not to bust chops or anything, but just a disagreement:

 

quote:

---

Originally posted by Kevin Shasteen:

Remember, the "Lag" is not a bad thing;

---

 

Well, some of us think it's "bad". On the street, if you come from no/low boost to boost (i.e., through the "lag") in a corner, it can be NO FUN - I can imagine a high hp turbo FWD or RWD car coming through lag halfway through a hot corner would be deadly!

 

Even some road race type cars with turbos get in trouble here - I've listened to enough race drivers say this about turbo porsches, etc. For drag racing, it's not a problem, since the system would be designed to never run through the lag through the 1/4.

 

quote

..its merely the time one waits for Boost to build. Therefore, in order to reduce "Lag" time, one must understand all the dynamics with which "Lag" is created; as in Pete's alteration of the Wastegate set up.

 

Personally, for a street car, that "wait" for the boost to come on is very bothersome. Certainly, I've gotten my OE turbo car to not lag as much, but it's still an issue. With a crank driven Roots or Lysolm supercharger, the torque and power are "right now". Same goes for a large displacement engine that's tuned (cammed, inducted, etc.) properly.

 

I've seen people talk about the kick in the back that a turbo gives. Well, I see that kick in the back as a signal that I wasn't being pushed in the back by the seat hard enough before the turbo spun up. I guess I look at the glass as being half empty .

 

Cheers,

 

[ August 28, 2001: Message edited by: pparaska ]

[Kevin Shasteen]

Originally posted by pparaska:

[QB]Not to bust chops or anything, but just a disagreement.

 

No Chops being busted here-I thrive on Hot Rodding Discussions; even if someones point of view differs from mine.

 

When I said "Lag" is not a bad thing...I didnt mean it was an acceptable phenomenon. What I meant is, Lag is simply a Mfg'ers compromise designed into the system; that once understood, can be minimized.

 

Just like that "Properly Tuned" supercharged set up, or the "Properly Tuned" Hi/Perf. N/A engine....for it to give that "Kick in the Pance" feeling at the desired moment-it must be "Properly Tuned".

 

The Mfg is never going to give you a properly tuned turbo set up-to many turbo's would expire under harsh treatments & abuse...all of which we call fun. The mfg isnt going to relinquish that control. So, we have to buy the product & make the changes...all in the risk of "Voiding" the mfg's warranty.

 

Once that warranty expires...all bets are off. Yea, I understand what you mean about the Supercharger's effect being "Immediate". Still tho, "Lag" can be minimized w/a "Properly Tuned" turbo system.

 

The hard part is determining what "Properly Tuned" means to the driver.

 

Kevin,

(Yea,Still an Inliner)

[pparaska]

quote:

---

Originally posted by Kevin Shasteen:

The hard part is determining what "Properly Tuned" means to the driver.[/QB]

---

 

That's a mouth full! And that's exactly why, as you said, the OE's have a hard time doing it and keeping the thing warrantee-able.

 

But that's where us hot rodders come in - WE decide what's right and build it for ourselves! (or pay Lingenfelter to )

[clint78z]

A turbo charger just make a slow ass motor fast. The 2.0l non turbo mitsu couldn't pass a medichair, then turbo it and yes there is a bit of lag at low end but it screams potential.

 

Somehow turbos always get a bad rap, or compared to an engine size more than twice it's displacement with a supercharger. I guess we need infinity to put out some twin turbo V8's to get everyone whistling a different tune.

[pparaska]

I think Bob Reiger (sp?) is doing a heck of a job convincing the drag racing street car set that turbos ARE a great alternative! As did the GN!