My Trans finally died!!

[Dave]

So why is this post in the performance section...

well, I've actually got a good reason for it.

I've not got a running (good condition) DOHC engine, wiring harness and computer - altho I won't need the computer or wiring, because remember, I'm goin' old-school on this project.

If no one buys my Z in the next week (engine and all) I'm gonna be pulling the motor, and welding together a nice little engine stand that will support this fine motor of mine, strong enough to even start the motor, and I'll start pulling things off, and putting things on, and welding stupid looking things together in an attempt to make a carb'd version with a standard distributor.

I know, I know, using injection will give better emissions, better fuel economy, better throtle response, etc - but this is a project I've been pondering for quite some time - for no other reason other then to expirement with making power in a way that no one else has with this motor.

If anyone has suggestions, pointers, or other helpful hints, I'm more then ready to hear them.

--Dave.

[Doubt_Incarnate]

go for it, i'd like to this up and running. i love that dohc motor even if it doesnt fit my car, i still like read the peoples articles and they stuff they do. i recomend side draft carbs, you could keep the whole pakage a lower profile.

[Dave]

I was actually thinking about doing that too, having 6 side-draft carbs bolted in some fassion directly to the head, and having something setup just to connect the coolant passages.

it sounds almost like a stupid setup, but if I can make something like that work, I'd imagine I could get a hell of a lotta power outta it.

--Dave.

[Mach10]

You won't get side-draft carbs to work all that well with this motor, given the angle of the heads.

At the high-end, you could probably fabricate a useable IR downdraft carb setup with a few smaller webbers (< 35mm).

A few things to note:
1) You will lose all streetability in running a setup without a properly tuned intake setup. Not only this, but you will be losing the mid-to-high-end gains from having the long runners and plenum space.

2) Fuel economy will be attrocious, tuneups will be hard, and there's no good way to filter air with an IR setup.

3) Have you ever tuned paired carbs? Not many have. It's a bear to do on my Jag, and that's only 2 of them.

4)After you get all 6 carbs to bleed evenly, then you have to map out an appropriate advance curve for the distributor. I'd assume you can use the distributor and module from an earlier RWD carb'd 2.8, but don't even think that the advance curve on it will behave properly with an IR setup. And then, after you've picked an appropriate curve (and found someowe to re-ramp the distributor) you'll have to re-tune the carbs... Then recheck the timing...


If you go ahead with this, I would expect that you will lose vast amounts of torque clean through the power band. By the time you get it performing at stock levels, the cams will have to have be more aggressive, and you still won't get anything remotely resembling torque under about 4000rpm or so.

Well tuned velocity stacks might work, but at the end of the day, given how ridiculously easy it is to get a 91-93 ODB1 LQ1 to run with just a battery hookup... You have to ask yourself: Um, why?

A normal four-barrel carb on this motor will kill it. Even a monster-flowing demon will not have the right kind of airflow velocity since you can't get an intake that will work properly with it. The intake and plenum that's on the motor already is more-or-less an advanced tunnel-ram manifold. You will be taking four steps backwards to take one forward.

A set of downdrafts will work (be prepared to spend an assload of money for them), but the side-drafts won't unless you want to build a riser off the heads. And you don't want to force the air/fuel charge to make 2 90º bends. All of your fuel will wash out on the intake.

It's one thing to go old-school on a setup that mimicks the airpatch of a carbed motor (TBI v8/v6, straight 6 etc). It's another to reingineer a whole motor that was built around a very sophisticated fuel injection and air-delivery system.

[Dave]

Wow Mach - that's some good info...

I've tuned IC setups (not just IR, but ind. carb setups) on chev V8's before - that's tough, extremely tough, took quite some time, but on top of that, we also had adjustability of timing for each cylinder +- 3 degrees so we had some extra flexability there - too many things to look at when tuning one of those motors. It is true that they don't make power till the higher RPM's, but the power they make at those speeds is awesome! I've seen an N/A - Ind. Carb. setup make over 500hp of course it didn't make much below the 4k mark, but this motor was built to be twistin' up to the 9500 mark.

Anyhow, I've looked at the distributors from the other 60* engines, but I still have the issue of clearing the head - granted, I can probably trim up that bit on the head, but I still don't think that'll offer me enough clearance - I'm going to have to get one of those distributor relocaters, or find a way to mount a front-mount directly on the int. shaft, or on the back of one of the cams (probe style)

I thought about doing 3 twins and finding a way to mount them to the stock lower intake manifold, and using the stock injector ports for N2O jets as an other way to destroy this poor engine, but I honestly want to see if I can get power in a way that no one else has before.

Altho, I haven't seen a successfuly supercharged version (not to say there isn't one, I just haven't seen it yet)

If there hasn't been a successfuly supercharged (centrifugal supercharger that is) then I may go that route too, before I start cutting things up and taking them apart.

now all I need is a 3bar map sensor, and some time to play with the bin files.

I've got several strange ideas runnin' through my head right now, and what all I can do with this engine - it's got a lot of potential, I just have to find the keys to release it.

--Dave.

[Mach10]

Ha! I didn't even think about distributor clearance....

Just based on that, it ain't happening. There isn't any way to clear enough material from the head without punching through an intake port and a water jacket. Even if you sealed the gaping hole up, I'd be worried about the integrety of the head.

On the other hand, I'm sure you can get an aftermarket spark-box to work with DIS.

But with that kind of money and wiring complexity, it'd be far better value to stick with the ODB1 and hook up the stock fuel injection.

It's not that I don't find IR downdrafts sexy (I do) it's that I really can't see it working properly with this motor.

If you want to get creative, supercharge it. It's been talked about, but AFAIK, nobody has EVER done it short of draping an m90 onto the lower intake and snapping a picture.

[Dave]

I should look for a wrecked supercharger that's gaurenteed never to work again, and ready for the garbage, that way I can figure out mounting hardware, clearance issues, plumbing, and all that good stuff.

I'd love to see IR's on one of these motors tho, I think it'd be the most sexy setup ever.

altho I pondered working with a couple engineer guys I know and seeing if we couldn't convert the motor to a 2stroke supercharged setup, using the exhaust ports only, and cutting in our own side intake ports - I wouldn't even want to imagine that pricetag.

--Dave.

[Mach10]

I don't know that mounting it up would be technically more difficult that bolting it to any other motor that doesn't have a specific manifold for it.


The lower intake manifold has all 6 ports lined up in a column. You'd need to build an upper that bolts to it, but also moves the ports in so that they are at least in pairs... or at least into a plenum underneat the 'charger.

For the throttle body etc, I'd just use what they have on the L67.

[Mach10]

I haven't really sat down and taken any measurements, but while the idea of a supercharged higher revving motor does make my loins tingle ever so slightly, I'll be honest; I much prefer a hard-running high-revving NA motor. While I don't have a great reference point for exhaust tone (mine was swiss-cheese welded to swiss-cheese with velveeta), this motor really starts to sing at around 6000rpm. Even with the holes in the exhaust, you can hear the intake. blower whine is cool, but not so much in a Fiero where I can hear every injector click. I've heard sound clips, and while my hat gets tipped just for sheer coolness, I never really considered a blower to be very... sports-car-ish.

I'm building a sports-car, not a drag car.

Turbos are a little better, since they sound extremely seductive at about 100,000rpm, but there's a lot to be said about induction noise with a free-flowing intake and a quiet (but free flowing) exhaust.


That being said, I need something to flex my brain while I work...

So,


To get that blower on top you need a few things looked after.

-First, the manifold has to be robust enough not to crumble when the drive loads up with tension (like when it shifts, or even just tightening the idler).

-Second, to get the most out of this intake, it'll need to be fairly open, with no sharp bends. You don't want a set of pistons running lean under boost because of huge flow differential between pots.

The options are of course to hack up the lower intake and weld a "box" to it, which will save you some hood clearance. You'll want to shape the ports fairly consistantly, and have at least a fair bit of open airspace under the blower to allow for some pressure equalization. Basically, you'll be turning that runner-shapped LIM into a single-plane manifold with a riser and deck for the blower to bolt to.

In fact, I'd almost suggest getting ahold of a 3800SC intake and trying to keep the same spirit of design (plus you might be able to hack off the mount plate. I don't think there's any hope in hell in being able to modify the 3800 intake... The head angles are different, the ports are in different places... It'd be a nightmare. ) But take note of the design cues in terms of runner shape and length.

After all that, you'll still need a fuel system. Granted, you can go with a more common supercharger and just slap a carb on it. But you'll still need to fart around with the ignition.

I vaguely remember a bloke on the Fiero forums getting some gears cut and manually putting together a belt-driven distributor on a North-star. That might in fact be a solution. You'll need to do your math VERY carefully, however. You can NOT have the pulley sizes off, or it will continuously put itself out of time with the motor.

IIRC, there are several kits available for a Small Block Chevvy. If you were able to make an SBC crank pulley fit on the end, you could just modify the SBC remote distro kit yourself. Belt-length will increase stretch (and may play with your timing under load) but the ads swear that the rubber belt gives more consistant timing 'cos they absorb crank/cam harmonics better than chains or gears.

If you can get that done, the world is your oyster in terms of old-school induction methods.

I still think you're wasting your time. The EFI will just work better with a bit of tuning.

[Dave]

See, I'm still really crossed between doin' the IR carb'd setup, and having some type of distributor - I'd probably end up being DIS, just because of the ease of it, and I'm sure there's some spark boxes out there that can help it work ... or I could go with the supercharged method - not the type on the top of the motor either like you're thinking, I'm thinkin' more along the lines of mounting one where the A/C goes, using a Centerfugal blower, like a procharger for example, running it through an intercooler in the front of the car (obviously) and comming up from underneath and hiding the duct work in the factory airbox and such.

as for the plenum, I'd knife edge the lower plenum between the runners, and take the factory upper manifold cut it in half all the way down, gut all the extra material out of it so it's a big open box, TIG weld the two halves together do some grinding, and make it look stock.

if I could get something like that to work, where you wouldn't see the procharger/vortec/whatever model used supercharger sitting down below, do a good enough job with the intercooler so it's not as noticable, and hide the duct work, you'd have a hell of a sleeper, that even if they looked under the hood, they wouldn't notice it ... right away.

The only reason I'd want a totally unusable supercharger, is I wouldn't want to spend much money in the R&D half of getting the plumbing together ... however, after I get all the placement issues worked out, then I may invest some money, get a working charger to match the one I had, get some engine dyno time somewhere, and build a program using a 3bar map sensor that would be streetable - then find a small car to tuck it all into ... something obscure like a J-body - granted, it'd still be FWD - but I can honestly say I've never seen, or heard of a setup like this in an early 90's J-Body, and those are pretty much disposable little cars, so you can find 'em anywhere.

I've got tons of crazy ideas - and if I happen to win the lotto, I'll turn this motor into a 2-stroke - but that's just dreaming - the sad thing about that tho, is I already know exactly how I'd do it...

--Dave.

[Mach10]

A centrifugal blower would plumb up pretty much the same as any turbocharger would.

Although better than nothing, I've yet to see a CF blower come close to the power output of a turbo charger running less total boost. The CF blowers tend to be lossy since you have to gear up the shaft to get the rpms, and there's a lot of drag on the crank from that.

About the only great thing that can be said is that a CF blower is consistant. It'll give consistant boost for a given RPM range much more nicely than a turbo, which in theory would make it easier to tune.

I don't know that I've ever seen a pull-through carbed CF supercharger, and I don't know that it would be a very good way to go. The fuel will probably separate long before it reaches the manifold.

A blow-through... hehehe... Have fun setting that one up!

I wouldn't use the upper intake manifolt at all, since it would offset the 'charger and/or carbs. You'd want it all centered so you aren't forcing a more curved airpath through opposing cylinder banks. I would create something new that kept the whole assembly equidistant from the head intake ports. The way the manifold sits does this because it has the plenum space underslung beneath the runners. You count the runner length from the plenum, not the throttlebody. The airstream comes into the symetrical lower intake vertically, so there's no length discrepancy.

The particular intake manifold that's on this motor is the major source for it's GREAT powerband. There is nothing else special about this motor. While the intake may be improved upon, I don't think anything more intrusive than smoothing transitions and a general port-match/polish will actually improve it any. Nor have I seen sufficient data to suggest that the manifold is in any way restricting the motor.

Look at what Kev did with just headwork on a stock intake. You can't tell me the intake/throttle body is restrictive when he picked up nearly 80WHP just from a port and polish. Yes, the rotating assembly was matched and balanced... But I wouldn't account more than a few percent of actual horsepower gain just from that (structural integrety and harmonic distortion improvements are awesome... But you won't necessarily see them that much on a dyno. You WILL see the benefits after running it hard for a few months then inspecting the bearings ).

I guess my whole bit is "Don't reinvent the wheel" unless that's specifically what you are out to do.

As for two-stroking this motor....

Um, wow.

As horny as that sounds, I'm not so sure you'd be picking up all that much since you are still needing to drive the rest of the valve-train.

The exhaust valves are shaped way wrong to be able to flow both the air, fuel, and exhaust demands of a 2-stroke.

The other problem is that 2-stroke motors do not make a lot of torque, and they need to rev up HIGH to make power. I'd be seriously concerned about the bottom-end scattering to the four winds the first time you tried to bouce 10k off it. I know that the 2-stroke minimizes the stretch stresses on a con-rod... But I'd be worried about pounding that bearing completely flat on each stroke, or shattering the piston.

In any case, how on earth would you separate the air/fuel streams? You need to fire on each rotation... I can't see any way of scavenging the exhaust while trying to pull an intake charge, considering the close proximity of the intake and exhaust ports. Even 2-strokes are "valved" somewhat, although this action comes from the piston itself. You mention cutting side ports... Which would mean drilling straight through an unreinforced block and into a water jacket...

Truly, the concept boggles my mind.

[mr_merkur]

hell if you were to put a stupercharger were the A/C is supposed to be why not just put an Air/water intercooler under your dash, run the intercooler piping to look like a cold air intake?!

[Dave]

MR. Merk... that's goin' a bit far - plus I want to try to hide any sign of a CAI by running the exhaust of the charger (pressure side) through the factory airbox and hose that way ...

I want it to look like, when ya pop the hood that there's nothing more then a factory engine stuffed in a small car - and that's even if I do go this route with this project - after all, if you gimme the word, I'll pull the motor for ya, and get 'er set up on a pallet and ready for transport.

--Dave.

[Mach10]

Anyone that knows anything about late-model GM will soil their pants when they see a TDC under the hood of a J-body...

From what I've heard from a lad that tried it, you will run into serious clearance problems as it is just from the width increase of this motor.

Actually, I'd like to see a TDC in an S10... Not that it's much of a truck motor, but I think it'd still be cool

[mr_merkur]

Dave, I'll know after we get the heads pulled from both engines, I kinda doubt half the heads will be bad, but there is a chance. On a side note I bought a new, well used tool box today. Craftsman with ball bearings etc., its a 2 person box hehe.