200 X-flow EA 3.0 results

[MustangSix]

I loaded the specs for the Locost engine with six 38mm Mikunis carbs, my cam, and the headers into EA and got these results:

266 hp @ 6000
255 lb/ft @ 5000

A little peaky, but powerful. I'm at the limit of what you should do with cast pistons.

This was with an unported head, stock valves and only 50% flow efficiency rate. Increasing the flow rate, opening the exhaust, a slightly bigger cam and a little more carb gets you over 300 hp @ 7500. Realistic? Probably not...... In reality I think this might be a 200 hp engine, but who knows where you could be with a little tweaking. M3 power levels?

 

[addo]

EA 2000[/b]":2ztyc9ai]Piston speed !!EXTREMELY!! high...

All in a lightweight package. It ought to get up and boogie. That's a pretty buzzy motor. Hope you're not running a 2.something rearend.

Adam.

 

[xctasy]

There is way, way more hidden there. I think the engine analyser is under estimating the power and torque spread. I can't prove it except by benchmarking it with other actual dyno runs of vehicles of less advanced breathing systems than yours (Minis and Holden OHV engines)

I have seen Minis with optimised scatter cams do similar specific numbers, relative to rpm and cubic inches. The pulse tunning of a correctly sized carb will give you a figure near to this. In Aussie, its nothing for 9 porter Holden 202's to get 254 hp at 5250 rpm with just a set of HIF 6 SU's, the stock cast XU1 header and a 308 degree cam. There is every chance these figures would be about 240 hp installed.

The limits to your cast pistons may be higher than you think, but its better to be safe than sorry. See how narrow things get from torque peak to power peak when the rev range goes up? I'd bet on a broader range than even the EA suggests if you have a duration of less than 290 degrees. The cross flow has near ideal approach and departure angles, and inertial ramming with just the right carb can exceed independant runner EFI systems.

Normally aspirated piston engines hit a wall where (rpm *cubic inches)/ power equals 3650.

At 266 hp at 6000 rpm for a 206 (60 thou over)cube engine, thats 4647.

(a Mini with a VP8 cam, one IDA 46 and 1435 cc reving to 7500 rpm doing 148 hp gives 4449)

At 300 hp at 7500 rpm for a 206, thats 5150. The number gets lower if the engine can handle the revs, it doesn't go up unless its badly matched.
I'd bet money you'd be getting 350 at 7500 rpm, more like 4414. A cross-flow Ford has a perfect induction system compared to an ancient Pommy Austin A-series! And sure as heck is better than any 40 year old GM Holden.

If you were to change the rods to 5.09 SBF and get custom pistons, and you'll see another 10 hp at 6000 rpm, by my calcs, with no reduction in torque. This reduces frictional losses.

 

[MandarinaRacing]

Jack the good thing is that that graphic shows that you would have over 200 ft/lbs @ 3000 RPM....so it still can be streetable.....and still have power to boot. Maybe now the potential of the X-Flow head will be more evident.

Alex

 

[Anonymous]

Bet you can hardly wait to try her out on the street to see how close you are to those numbers!

Doug

 

[MustangSix]

I get closer everyday. Ok, not everyday, but I'm making some progress.

Here is the six in a row 38mm Mikuni setup I cobbled together. Now for a half dozen flanges and some tubing.......

If I put individual K&N's on these, they'll stick out of the side of the hood. Cool looking, but maybe a problem in the rain? I'll come up with something. This is pretty peaky compared to a stock 250 or 300. I'm planning on running a 3.55 rear, but maybe I should find those 4.11's I have on the shelf.

Xecute, I ran several other permutations of EA on this setup and can get a few more ponies out of tweaking the ignition, cam specs and timing, tuning the headers a bit, and doing just some heavy porting. I maxed out at 397hp @ 8250 rpm but the curve is like a light switch. It makes 7 hp at idle and goes straight up from there. The torque curve looks just as steep.

At any rate, the bottom end I've built would never survive those numbers. And I'd definitely have to do something to improve the oiling. Conclusion - you can probably improve peak numbers considerably, and with electronic engine management you could approach or exceed M3 power levels. All I need is $10,000 to build such an engine!

 

[XFlow_Fairlane]

jack easy rain solution...get some loose fitting tin cans you could drop over them...maybe a little teather or simple lip on them

nick

 

[MustangSix]

Yep, carbs! It's actually easier to mount these than I thought. I spent part of the afternoon cleaning the bowls, checking float levels and pondering the fuel and vacuum lines I need.

I also connected the fuel pressure regulator to the mechanical pump. I think I'll try 1 or 1.5 psi to start. These carbs are gravity fed, so too much pressure might overwhelm them. I ended up with four fuel feeds because of the way the two sets went back together. The outer pairs have a tee'd feed, then each of the centers have an individual feed. I'll just build a fuel log with four outlets.

Each carb has a vacuum nipple on the top so I'll have to build a vacuum manifold to connect the trans modulator and PCV.

The choke actuator is near the front carb and is facing forward, but I may be able to rework that to make it work from one of the rear carbs.

I made a couple of S-bends from 1.5" tubing to match the carb positions to the inlets on the head. I'll get my machinist buddy to make some flanges for me then I'll weld the S-bends to be the stubs to mount the carbs.

One set of the carbs had a throttle cable. Perfect shape and length, so I think I'll keep it. I will need to add one more cable to activate the trans kickdown.

I'm still not sure on air cleaners. I may try to make something out of aluminum sheet. It'll add to the handmade look and I can make it more weather proof than K&N stubs.

Just for grins, I also set them alongside the log head that I cut the log from. It wouldn't be too hard to braze some stubs into the intake ports.......hmmmm......Maybe Ak was on to something 40 years ago.....

 

[Asa]

one very loooonnng air-filter would be cool... then again, you could do something similar to headers, some pipe running from each merged into each other all running to a big pipe hooked up to a K&N cone filter...
it could be a B!+ch to work on the engine with it, but it would def. be different

 

[MandarinaRacing]

Just for grins, I also set them alongside the log head that I cut the log from. It wouldn't be too hard to braze some stubs into the intake ports.......hmmmm......Maybe Ak was on to something 40 years ago.....

Alex

 

[xctasy]

Happy brazing and TIG welding dudes. Garnish the dish, and buy all the bike carbs you can boys.

Great idea Jack, MandarinaRacing, and Ak Miller. I'm in awe!

 

[MustangSix]

There was a post the other day about performance fuel pumps so I went back to the shelf to look at something.

The Oz pump is nothing more than a Carter pump made under license. It looks a lot like some V8 Carter pumps. I had shelved it because it had an extra line for fuel return, but when I disassembled and cleaned it, I saw that the return was simply plumbed into the same chamber as the supply, so it was easily blocked off. Actually, I made use of it as another supply line because it lined up well with the location of the regulator.

I'm not sure if Oz pumps have any more capacity than the US pump, but it looks it and is more substantial.

 

[addo]

The highest flow rate Oz six pump was the "250 crossflow with power options" one; it was a V8 pump with the Aussie six arm (different to the US six arm - ask me how I know ). Other than that, the 64-66 filter canister units had a slightly higher nominal pressure than the later units... But they all take the same rebuild kit. The 2V fuel pump was a sealed V8 type unit.

Adam.