Putting a 2200 cfm throttle body on the same chinesium intake we been dynoing with along w a set ofatch flowed 63 lb injectors, then after every ounce of hp is wrung out switching to stock 500 efi mpi then adding highly modified 500 efi pieces one at a time

Smitty .... what you using for a controller? HP would be nice ....

That's a chit ton of work for real results - super cool! I know that you've done a lot of work with the mpi manifold before but I'm curious to see where it's limitations kick in.

Using mefi since i own a bunch of it, other than manual tuning its 1/5 the price of holley

Air sucks today, observed numbers down 21 hp, corrected numbers down slightly, its not perfect. Went up 3 jets on norms modded 4150, gained 2ft lbs corrected, lost 8 hp corrected but back to back against tims carb w real close afrs still made 16 more hp and 9 ft lbs tq. Tims FA made no difference fwiw, Smitty

Just checked ign timing, was down 2 degrees since it was set a while back, reset it where i been making best overall power, repulled, found 10ft lbs of tq its been missing for a while (back to 627 w mufflers), picked up 10hp and got it back in mid 670s with todsys air corrected, retarded cam 2 degrees from where i been running it, reset timing, pulled again, lost 20hp and 17 ftlbs tq, it really likes where its supposed to be, pretty much what bob m has told me all along!

Good to know about flame arrestor !

While motor is still warm, put cam back, reset timing, made 674.4 hp corrected thru mufflers and 686 wo mufflers today , doesn't matter hp wise if its at 13.5 or 12.8, same hp, slightly better torque, no more power to be had found from cam timing, igntion timing, othrr carbs, jetting etc, its maxed w what it has. Testing speedy2/33 outlaws carb when it comes then moving on to efi, will be consulting w bob m on a cam change, will try looser lash loops too, Smitty

What's your pipe length from collector end with and without mufflers ?

header tubes are 32" long, collectors are 4"x 24" from merger to tip when running open headers, similar in length to boat tailpipes. When I run mufflers I use 4-5" connectors to a 5" 90 hooked to a 5" 90 with gibson 5" id boat mufflers, its 60" from where it goes over collector BUT goes up in size at that point, when its slipped over collectpor I slide them on 5" or so so its effective length is 55" to tip, I picked up virtually NOTHING from having them on to open headers on 560 hp 502 I dynioed last, this motor religiously picks up 10hp and ft lbs tq when I take them off, Smitty

Smitty, I now proclaim you the "Bill Grumpy Jenkins" of marine engines !!!!

Thats some cool info.

Did you notice a difference lbs per hr fuel consumption between Tims carb and the custom 4150? Curious to see if its making less power, with less fuel, or more fuel. I would think if its making less power, with more fuel , maybe a sign the atomization is not as good?

What list number was the stock dominator ?

Scott, here are the double 5"90s and mufflers i was talking about

Both dominators were same part number, 8896.

5800-6000rpm 540

Total collector length includes pipe length bolted to it if same size

Note: I ran this for PapaSmurf's MER 540 700hp engine that was having some water reversion issues. He made his pipe 20" total length and it stopped reverting.

Note 2: Running tuned length does not always add Peak HP, but a lot of times if really fattens up the torque curve. Really depends of course how far off the original sizing was.

3rd Harmonic = 38.8 inches long ... more bottom-end Torque
4th Harmonic = 19.4 inches long ... highly recommended , best Torque Curve
5th Harmonic = 9.7 inches long ... reduced Torque , more top-end HP sometimes
6th Harmonic = 4.9 inches long ... reduced Torque , not recommended

Tuned Lengths= 19.4 best and also 9.7 or 38.8

Heres a good article that shows the importance of booster design. Even though the downleg booster carb flowed more cfm, the annular booster made more power.

Take a look at the torque numbers below 3000rpm. The annular booster is KILLING the downleg.

And you wonder how many guys slapped on an old swap meet dominator on their street car with a tight converter, and wondered why it was a slug and got chitty mileage

http://www.hotrod.com/articles/carburetor-showdown/

Spent a few hours reviewing dyno data today after shaking this out. Before fattening up norms modded 4150 we were in the .52 to .55 bsfc range from 5600/5800 up w afrs in the mid to high 13s (not sustainable afrs for 10 minutes at wot). Didnt really matter either between norms 4150, both doms or either intake, all in same range.
Fast forward to tims carb, bsfc's at hp peak and pretty much from 5800 up in the .61/.62 range, 398 lbs per hr fuel to make 650 corrected hp w afrs in 12's, thats 800 hp worth of fuel at .5 bsfc to mske a measely 650 hp, now before we blame his carb lets look back at combination, 8.5-1 548 w 252/259 @.050 cam on 114, not a rea efficient combination. And if you go back a few post you will see we poured some more jet to norms modded 4150 to drive afrs into the 12's to.make a fair comparison between tims QF and the modded 4150. Still made sbout same hp and beat the QF by 16 hp and some tq BUT bsfcs ALSO went into the .56 range then to the .59 range at hp peak, on last muffled pull used 375 lbs fuel per hr to make 675 hp, thats 750hp worth of fuel at .5 to make 675 hp, not very efficient at all, now, this IS from 5600/5800 up so not completely end of world but not patting myself on the back for making inroads here either!! Going to proceed w bolting all the efi stuff on too and see if things change much. Havent decided on next cam to test, if we can make same hp and pick up some tq w a little less cam plus increase efficiency a little i might go with it but if its going to take 800 hp worth of fuel to make 675 hp and motor makes 502 tq numbers like this I will be looking hard at going bigger and going up in compression, Smitty

One thing I noticed about tim's carbs, was the fuel curve seemed very stable thruout the rpm band. From 3000 to 6000 rpm, the air fuel ratio, didn't vary by more than 2 tenths. at 3k, it was 11.9, and by 5900, it was 11.8. I do like that . I've seen some carbs, vary big time. Some at start of the pull are pig rich, and by the time you get to peak HP, its piston burning lean. Or some start out in the 13's, and end up in the 10's at peak hp.

If i recall, with the stock out of the box jetting and what not, it was the same fuel curve shape, just was in the mid 12's for afr. We threw some jet at it, and lost like 3hp or something, and gained a couple foot lbs.

Looking forward to the efi testing!

Yes that was nice to see, also the gains and losses by changing jet was not nearly as much as people think, they say oh it's rich I'm losing 60 hp... no your not.... unless something is big time wrong, we changed at least 1 point in air fuels and only lost 2-3 hp, gained 6-10 ft lbs to

Full Force,
I am more than likely going to have to upgrade my flame arrestors. Need to do a bit of testing early season but really think they are restrictive at this point. What are you using that proved good in the testing on this thread?

Thanks,
Mark

Mine are 8" round 3" high, I gutted them though and only have a single winding in them.

I need to cut 1/2" out so they will be 2.5" now but was assured that won't hurt me .. need to clear higher intakes

I am thinking going with 10" X 5" Gaffrig so I should be good. Was considering 9" X 5" K&N but think the consensus is they are restrictive as well.

Mark

my K&N sure wasn't accordiing to the dyno.
I agree, you certainly hear that line quite often.

Do we need to start a "What happened to Artidfriends" thread? ;)

This has been my favorite entertainment of the day!

Did the same thing with a 5x10 on the dyno with some 600 hp engines and didn't see any change. Id be a little sceptacle running on the water that way though. You can see right through it and might just as well not have anything. I certainly thought about it though.

Baselined motor today at 682 coreected with mufflers, swapped to the cs test carb, went to 15.5 at 4800, called it a day till tommorrow, norm tested the fuel curve of the cs carbs strength to pull fuel while he was rebuilding it and said he doubted it could provide as much fuel as air it flowed and was real against even testing it in fear of hurting motor. Ill be dsmned if it didnt do what he said it would do but i DIDNT hurt the motor, going to crank up.main jets to huge ones and see wtf happens tommorrow, its all i got for now. It seemed crisp whacking the throttle. In middle of all of it today found bolts falling out of ati super damper and starter **** the bed!

Raceboat style!! lol

He is busy wondering how many of us are having as much fun as he is. .
Somebody has to do it . Im glad he is sharing

CS aeresol carb is a hand full. After ALOT of jetting, stagger jetting etc got afrs somewhat right at wot. Was able to get almost 669hp out of it at 6400 corrected (620 something observed), our base line was 682 hp (650 ish observed) with modded 4150 with mufflers the day before, air wasn't nearly as good yesterday and if i hadnt spent 6 hours trying to get a clean run with CS carb i would have base lined it with modded 4150 to have true comparison same day same dyno. With modded 4150 i have seen observed hp in the 625 to 632 range on days with cf of 4-5% fwiw so again, , corrected to corrected the CS carb falls about halfway between the modded 4150 and the 2 dominators and tims quick fuel, beating them by about 12 to 14 hp, lagging behind the modded 4150 by about same amount depending what day you want to compare. I wouldnt HOWEVER run out and buy a aeresol carb yet as afrs were pig ass rich at part throttle, it had a weak fuel signal and needed almost 100 main jets WITH power valves to not run lean on top, afrs were uneven side to side then after stagger jetting would even up then invert to too rich/too lean where it was just the opposite. Official done testing anymore carbs on this engine, giving all carbs back to their righful owners and even drug out a few good carbs i own including a nice 950 hp after norm showed me what holley did wrong with them and put them on ebay because IF i ever put a carb on anything of mine again EVER which i probably wont do i would just give norm a stack and say build me one! Now on to efi if my parts ever show up!

[QUOTE=articfriends;4533411].....Official done testing anymore carbs on this engine, giving all carbs back to their righful owners and even drug out a few good carbs i own and put them on ebay because IF i ever put a carb on anything of mine again EVER which i probably wont do i would just give norm a stack and say build me one! Now on to efi if my parts ever show up! /[QUOTE]

I don't know about that. Carbs are wonderful devices. Simple and you can pretty much make them do anything you want with a small handful of brass parts. For marine use, about the only negative (and it is a big one) is that they can fill your engine bay full of gas vapor. That's a pretty big argument in favor of EFI right there though.

I love what you're doing here. I really like the fact that you are doing it with a real world (low compression) engine and not something requiring avgas or whatever as the ultimate shootout engine. I like your attitude of building an engine that can reliably run 20 minutes at full throttle. And then do it again. Endurance race engines might be the toughest to build.

Thanks for sharing your research. I'm really enjoying it.

Dan

Post #63

Unless you raise the injectors up in the runners.. not at the base like they usually are. Think Nascar of today....Old news that has been used in Formel1 and tintops since 60's. Stack injections wake up with on top injection and a plenum on top... sorta like putting a Big plenum on top of a tunnel and injectors there in line above throats.

Chasing 17-20,000 rpm gives you really short intake tracks!

Look how tiny that clutch is, and how low (close to the ground) that allows the crankshaft to be. Just beautiful.

Look at how many plates that clutch has.... Short runners or not (those are variable) Never Ever put the injectors washing up the valve stems from lube like it is the norm for OEM engines... Just look at every injection, even mechanical form early 60's including Crower ( which was what KAM used) back in the day. * Thats why Carbs usually beat EFIS for top hp...

FI on performance motorcycles were a step backwards powerwise for a while until they put a second injector further upstream in the intake, and that was a major game changer. I have never once heard any racer say that they miss carbs after that. Are there two stage injectors on these bigger motors?

Last day of carb testing, was going to be done BUT norm and i decided to do what we could to straighten out f2speedy/33outlawsst's cs carbs. Norm calculated what size the power valve feed resttictions would need to be to get a nominal increase in flow when power valve opened so we could jet his primary main jets leaner but still get enough fuel flow at wot to support his hp goals. So we opened up the feed holes with a #47 drill and went down 7 sizes on primary main jets. His cs carb made good wot hp at a safe afr BUT having to use a #93 main jet put afrs into mid to low 11s when i dragged the dyno brake at 2800 to 4000 from 250 to 375 ft lbs. After the mod of course we had to see where we were at on dyno. With power valve closed at a part throttle load we were now able to get mid 13s and then go richer when you leaned on it at wot. Previously it did the opposite! Called it a day, looked at afrs at 5500 rpms and about 625 hp load and decided what jets HIS carbs would need for safe starting point. Im quite impressed w norms nowledge and ability! We slapped a prototype carb on that norm built and is experimenting with, did a few adjustments then called it a day! All efi stuff happened to show up today, starting to bolt all that on Tommorrow! Btw, check out the adjustable cam linkage norm built for progression rate of secondarys!

Prototype carb he built, notice anything missing?

Everything. Where are the mister thingamajigs? Never mind the choke and J-tubes. ;)

Missing MORE than that in appearance