Building a N/A 2.3L

welcome, read the sticky tech thread and run a search. This get's asked more than once a week often.

turbo is the easy way, so you are in for a challenge doing it n/a. My website has some good n/a info if you'd like to review it.

prepare to dish out the money. For 200hp, you are going to need one hell of a nice head, tons of compression (read race gas!) and a lopy cam that you don't want to drive on the street. I can't imagine making more than 160hp on an easlily streetable 2.3 NA.
Go turbo. They come stock with 200hp, and **** loads more torque.

get a decent block, bore it .040, put some new forged pistons in it, get your head ported like crazy with large valves, longtube header, gutted intake manifolds, a huge lifted cam, get 42lb injectors, and spray a 200 shot in there and you'll love it. of course you'll have to fill the bottle up now and then but it should be fun.

I'm working (slowly) on building a carburated 2.3L with more HP than stock.

This 1981 article from "Hot Rod" magazine has been useful:
http://www.dpo.uab.edu/~bmclean/pages/m2_faq2.htm

Basically building horsepower with any small displacement engine requires either forced induction (turbo or supercharging) or LOTS of RPM.

A N/A 2.3L can make 200 HP but only at a significant RPM (like 7000). Getting 150 HP is much easier. The article has a fairly simple receipe for 150 HP: a mild cam, 4 bbl carb and intake, and a header. Their dyno work showed an increase in both HP and torque at streetable RPMs.

This is the direction that I'm heading in. I just have to keep from going overboard in any one area. For example I'd really like to use a big-valve head, but am afraid that I'll wipe out low-rpm torque.

Esslinger has a new "hipo" 2.3L aluminum head available ($1500), and Rapido has a new "stock" aluminum head ($999). Either might help performance at higher RPM. So might the Volvo DOHC head conversion.

I keep wondering if the the same tricks used to hot rod the 5.0L EFI engine might be used to get more HP from the 2.3L EFI engine. I noticed that Racer Walsh has a large-bore throttle body. If I was doing it, I'd use the later mass-air EFI 2.3L engine and work my way through the Ford Racing 5.0L book. Use more cam, higher compression, ported intake and header, and a chip to run it all.

78CobraII

Great post 78cobraII.
I beleive you are right in being concerned about low end torque. A lot of the current 4 cyls that you see in the civic, focus, ect like to rev, and make a lot of horsepower, but they have several tricks that let them keep the low and midrange power as well. They have variable cam timing, variable intake runners, and 4 valves per cylinder. Working with a 2 valve engine that has none of that really restricts our opperating range, and doesn't allow for peak power at 6000+rpm without some major loses in low end torque and drivability.

78cobraII, where can i find a 4 bbl intake? My next project is a t/c bottomend,intake,cam,lots of nitrous[hope for 250hp worth of no2] ported head,long tube header and carb. This will go into my drag setup stang. Witch has 90/10s,50/50s,subframes,3:55s,pro-stars and fuel setup.

who might know who has a chip for the SPEED DENSITY set up. 87 milled ported cammed header and kicks **** at 6000 rpm's but wants to go higher but the stock ECM wont let it rev higher,HELP!.

Hey, I'm posting to thank 78CobraII for his insights and the HotRod link. Although I have the newer EFI engine, my dyno pulls might give you some new insights, I dunno.
Anyway, thanks for the post.

Touring23, I'll definately be checking out those dyno pulls.

Tiny4lx, I bought an old Offenhouser dual plane intake and Holley 390 cfm 4bbl on eBay. Its not the best design in the world, but there's not much choice out there. I'm having to clean up some rough casting places where the airflow leaves the plenum. Racer Walsh may still have some of these intakes.

A better solution, especially for "D" port heads is to use an EFI lower with a 4bbl adapter plate. Racer Walsh discusses the EFI lower in their catalog and used to have the 4bbl adapter, but only carry a Holley (big) 2bbl adapter now. It shouldn't be real technical to make one though...an inch thick chunk of aluminum in the proper dimension and a hole saw would get you most of the way there. An EFI lower should be pretty cheap in the junkyard...you just have to clean up the transition area a bit and plug the injection ports.

Possible bad news on the 4bbl...not any carb will do. Holley used to make a 390 cfm 4bbl (List# 6299-1) especially for big 4 cylinder engine use. Apparently the current 390 cfm carb (List# 8007) is different in some way. I asked the Holley tech line if the current carb could be converted and received a "no" without any tech details. If somebody knows the answer I would appreciate it... Racer Walsh still sells them, but they are pretty pricey at $350.

Racer Walsh (geeze I'm sounding like an advert!) sells some sort of fuel restrictor for the 350/500 cfm 2bbl and an adapter for the EFI lower pretty cheap. For an early '80's 2.3L with a 1bbl carb, the 350 cfm 2bbl carb and EFI lower would give a heck of a improvement in breathing! And cheap too if you use junkyard parts!

Here's a link:
http://www.racerwalsh.com/2300_intakes.htm

78CobraII,Hollysh** that was good info.Thanks or the response.

"thanks for the response"I forgot how to spell "for"duh.And other words. Its 5:55 am.

Touring2.3,

I looked at your Dyno graphs and noticed something interesing on the Torque graph. You seem to have a small dip between about 3250 and about 3750 on the output from both dynos and a smaller dip in the HP lines. Any idea what is happening here? Your A/F ratio shows a spike right before this point...

Its kind of hard to compare the engine dyno results in the old "Hot Rod" article with your chassis dyno results...but I tried.

-Your torque peak was at ~2800 RPM vs. about 3750 for the old stock 2.3L carbed engine. You were up about 5 ft. lbs. Both are good.
-Your HP peak is very similar to the stock older engine. Not so good.

The Stage 1 engine in the "Hot Rod" article went from 100HP @ 5000 RPM to 150 HP @ 5500 RPM and from about 120 ft. lbs. @ 4000 to 152 ft. lbs. @ 3500 RPM. They did this with a mild cam, 4 bbl carb, a distributor recurve, and full length header.

You have several advantages over the Stage 1 engine...a cam with more duration, larger valves, more compression. You equal the Stage 1 engine in with your header. You don't have as much lift in your cam, but the roller profile should make more torque than theirs.

So what are we missing? In short...I dunno.

The engine dyno probably shows 10% higher numbers than a manual transmission car on a chassis dyno. That accounts for some.

I would think that your larger valves would compensate a bit for the lower lift cam. I wonder why Racer Walsh's roller cam doesn't have more lift?

Your A/F ratio seems to drop off quite a bit over 4000 RPM. I wish that the old article had A/F ratio. It would be quite interesting to see how the Holley 4bbl compared to EFI.

Is there any evidence of pre-ignition above 3000 RPM? Does your ignition system retard the ignition when ping is detected? What grade of fuel were you running on the dyno? Can your ignition be advanced manually? Can your fuel pressure be raised more?

78CobraII

Hi 78, thanks for the response, it's a lot more than I expected. I agree with your analysis, something's amiss. I know this engine is capable of more than 100. The only conclusion I can come to is that the header is too restrictive above ~4000 and I'm in the process of building a 1 5/8" header now. The dyno'd header has some 37" of 1 1/2" primary whereas the "Hot Rod" article used 26" I believe. Guess where the Helmholtz calculations place the torque peaks for the two headers: yup, 3000 and 4000, respectively. I tried the Darcy gas flow calculations but without accurate EGTs it's an academic excercise, at best. Anyway, I thought I'd put the conclusion at the top of the paragraph instead of burying it at the bottom. Here's some feed back to your specifics:

I looked at your Dyno graphs and noticed something interesing on the Torque graph. You seem to have a small dip between about 3250 and about 3750 on the output from both dynos and a smaller dip in the HP lines. Any idea what is happening here?

Click to expand...

You know how both the intake and exhaust are affected by reflected waves? For instance if a reflected high pressure wave arrives at the intake valve at the correct time cylinder filling is enhanced. I believe that dip is indicating an odd harmonic: Either a high pressure wave at the exhaust or conversely a low pressure wave at the intake. Maybe cross-talk from the collector or intake plenum??? I'm hesitant to question the ignition/fuel mapping because it's such a localized dip. Natch, the HP dip is just the torque dip displayed a different way.
*Edit* I see the same dip in Brantley's dyno curve, so I wonder if it's an intake signature?

Its kind of hard to compare the engine dyno results in the old "Hot Rod" article with your chassis dyno results...but I tried.
-Your torque peak was at ~2800 RPM vs. about 3750 for the old stock 2.3L carbed engine. You were up about 5 ft. lbs. Both are good.
-Your HP peak is very similar to the stock older engine. Not so good.

Click to expand...

Yup. I came to the same conclusions.

I wonder why Racer Walsh's roller cam doesn't have more lift?

Click to expand...

Yeah, you know, this is a Crane cam and every time they add lift (.420",.450", .480") they increase the duration (226*,232*, 240*), so I wonder if they're keying off of ramp rates and valve float? FWIW, when I queried my Dyno2000 simulation to find the "BEST HP" cam for this combination it came back with this cam, retarded quite a lot, and with more lift. SIC ~9:1 compression.

So what are we missing?
Your A/F ratio seems to drop off quite a bit over 4000 RPM.

Click to expand...

Yeah......<scratches head>

Is there any evidence of pre-ignition above 3000 RPM? Does your ignition system retard the ignition when ping is detected?

Click to expand...

No evidence of pre-ignition or ping, and it doesn't have a knock sensor.

What grade of fuel were you running on the dyno?

Click to expand...

87 consistently, no funny additive business. K.I.S.S.

Can your ignition be advanced manually?

Click to expand...

Sad to say, no.

Can your fuel pressure be raised more?

Click to expand...

Sure......But......it's aleady pretty rich at ~12:1.....???
FWIW, here are some other checks:
I looked for a dead hole but compression checks out OK around ~155 psi.
TPS checks out: 4.8V at WOT.
Oil pressure is excellent (~35 at idle up to ~60 at redline).
Transmission losses? The Trac-Loc is still tight up to the limits of my torque wrench, 100 ft-lbs. Could be a slipping clutch but the olfactory alarm isn't going off. Oh. Duh. Torque is torque. It transmitted ~126 ft-lbs OK at ~2800. OK, eliminate that question mark.
The back pressure test shows the exhaust isn't a restriction aft of the header.
Check out what happened when I disconnected a coil pack.
I never flow benched the ported head; it might not flow as well as we would expect, perhaps even worse than stock

Anyway, thanks for the response and hopefully you're getting some benefit, too....? What not to try?

*Edit* 350-390 CFM seem like a lot of carburetor, you're not worried about throttle response? That's the equivalent of 966 CFM for a 350ci (!) I mean, you only need to fill one cylinder at a time with the four cylinder.

*Edit* 350-390 CFM seem like a lot of carburetor, you're not worried about throttle response? That's the equivalent of 966 CFM for a 350ci (!) I mean, you only need to fill one cylinder at a time with the four cylinder.

Click to expand...

I hadn't really thought about throttle response...the "Hot Rod" article showed that the engine really responded to the extra carb on the engine dyno, even at lower RPM's and just with bolt-ons (carb, intake, mild cam, header). They didn't comment on throttle response...it would probably be difficult to guage on the engine dyno anyway.

The stock Holley-Weber 2bbl is something like 230CFM, but its a progressive 2bbl...you drive most of the time on 1bbl. The Holley 350 cfm 2bbl runs with both bores open all the time...like half of a 4bbl. The Holley 390 cfm 4bbl will run on only 2bbls most of the time (assuming I can keep my foot out of it ) but the primaries are smaller than those of the Holley 350 cfm 2bbl. Racer Walsh used to claim that the 390 cfm 4bbl got better gas milage than the 350 cfm 2bbl, and it makes some sense when you compare the primary bore sizes.

Let us know if you find out what's holding your engine back.

Here is a small webpage I have started on my 2.3L powered '78 Ghia. I've put up a handful of pics of the parts I'm using, but I'm at a pretty early stage of assembly so there not much that's finished...

http://www.geocities.com/m2cobra78/

Yeah, yeah, its a little pimp car...

Nice!

Excellent thread here.

Touring23, I would guess the torque dip might be because of destructive interference at that RPM point in the header. Something about the point where the exhaust gases collect a pressure spike is distributed back up the other tubes from whatever one has an exhaust pulse exiting at that time, and if the spike hits an exhaust valve in time for its opening it will interfere with cylinder scavenging. (My theory my be a little off here but soemthing like that.) Anyways, the shorter the header, the more often the interfering pressure spikes can bouce up and down the primaries, and the greater the chance of hitting an opening valve, which is why a long tube header makes more consistent torque with respect to RPM as well as more overall torque. But even a longtube will probably encounter interference at at least one point. Anyways, I am not sure if that is what you are looking at.

Where can I find these equations you're talkin about? What information do they give you?