low compression 548 dyno testing has begun!!
 

Finally got 548 on my dyno, this is going to be a LONG , extensive dyno test comparing the merits of different intakes, carbs, manifolds, throttle bodys, stock 500efi intake, highly modified 500 intake, speedmaster chinese open plenum intake, edelbrock 454r victor intake, cams, cam timing etc. The "mule" motor is a 8.5-1 548 w afr 315's that been re-cnc'd to flow over 400 cfm. The first test which is 80% complete is to establish a baseline using the chinesium intake which is similar or same as what tim full force had on his 540's. I bought a 180$ speedmaster efi rectangle port intake and efi rails to use for this. Overall at first glance intake appeared to be a nice piece for the money.

When i ran the inside calipers thru all the ports to get a idea of how uniform it was i found 6 of the runners to be fairly uniform in CSA and #2 and #7 to be approx 10% smaller. As far as "core shift" and other alignment, i found zero problems. I spent about 6 hours w a die grinder and polishing rolls port matching intake to heads and opening #2 and #7 up to match, i'm no rick lappoutre or jim valeko but i do my best.
For first test i used a holley 4150 850 that has been modified by my dyno partner norm schenck that has 40 plus years of modifying holley carbs.
http://www.compfuelsystems.com/
This carb is highly modified and flows well into the 1100 cfm range. The manifold has a dominator 4500 bolt pattern, we mounted carb with a 2" tall 4150 to 4500 adapter and a 1"phenolic open spacer to straighten out airflow. As far as dyno dress of motor, no accessory's , 2.25 dia race car headers, 4" collectors going into 5"tailpipes w gibson marine mufflers clamped on to keep neighbors happy. Our depac sofware uses J607 CF which most other shops use and it does yield slightly higher numbers thsn sae1349 like mercruiser uses. We have had pretty good air so our CF has been around 3%. We started w 93 octane, after some tuning we made 674 hp around 6200 and 620 ft lbs tq at 5000.
5800-662.8
5900-667.6
6000-671.7
6100-672.6
6200-673.8
6300-672.6
6400-668.3
6500-665.4
6600-657.6
Tuning is NOT complete as we ran out of big enough carb jets to get mid range where we want it and timing is all in by 3500 rpms at 38 degrees which is doing torque no favors (when we test with efi on and can tailor timing curve i expect tq gains,as this motor previously liked 30 or 32 degrees in mid range). Switching to 89 octane picked up hp to 677 and torque to 627
58-664.2
59-671.7
60-674.5
61-677.3
62-677.6
63-672.7
64-670
I will be testing also with 87 octane once efi is bolted on and knock sensor is present and working.

After switching to 89 octane and pulling i then removed mufflers to see IF there were and gains to be had, hp went to 687 and tq went up to 639.
587-666.6
58-672.0
59-676.1
60-678.1
61-680.4
62-683.2
63-687.1
64-679.6
65-673.1
The cam, motor has a cam motion hyd roller previously spec'd by Bob M for the blower motor that was in my Baja. 252/259 duration at .050, 114 ls and .660/.654 lift. Running isky red zone solid roller lifters at .010 cold, haven't played with lash yet but hot intake changed to .006 and exhaust went to .012/.013, td 1.7 shaft rockers w aluminum intake rockers and steel exhaust rockers. Springs are isky tool room at 225 seat and 525 or 550 open (cant remember for sure anymore)

I then swapped on a 454rVictor intake with port matching and slight plenum divider work. With mufflers on it made 2 to 10 more ft lbs tq from 3200 to 3900, was almost identical from 3900 to 4300, the speed master pulled away from it from 4200 to 4800 by 8 to 10 ft lbs, they were close to even from 4800 to 5300, from 5300 to 5600 454r made 3-5 ft lbs more. With 454r tq peaking at 5100 and speedmaster tq peaking at 4900/5000. From 5600 to 6100 speedmaster made 5 to 10 more hp then from 6200 up hp was almost identical with speedmaster making 677.6 at 6200, 454r making 678 and change at 6400. So they were overall pretty close.

Speedmaster intake is back on and we are testing a modified dominator next. I also advanced cam timing 3 degrees since cam is obviously too big for such low compression and surprisingly motor gave up 10 to 12 ft lbs of torque and hp on the upper end and at peaks, i expected hp to drop but thought it may help lack of upper midrange torque , it did pick up 10 to 15 ft lbs torque from 3100 to 3900 where i DONT need it.

Duplicate post

I plan on testing retarding cam and going richer with carbs in midrange to see if it picks up some more torque. My goal is to try to make 700 reliable hp on 89 or 87 octane gas, we are already close. When done i plan on cloning what ever combination works the best and putting these in my 33 scarab avs. It already pulls 30 merc labbed props to 5600 and 84/85 mph with stock 500 efis so i dont need 700 ft lbs of tq to get boat moving, i need a high rpm motor that pulls on top. I have pulled this to 6700 on dyno and we were still in the 650 to 660s. I previously dynoed this with modified 502 mpi intake and 8.4-1 at 627 hp at 5600 on my dyno and less peak tq, fwiw the open plenum intake and carb makes about 75 to 80 less ft lbs of tq at 3400/3500.

Any flow sheets on heads? or pics of the intakes?

Impressive

it is, with low compression and too big of cam, if I am around them numbers with new builds in marine trim I would be super happy, gives me some hope....

I didnt get flow sheets when heads came back from Tony Mamo after Bob M had me send them to him (was 2 1/2 years ago) , I did get them in a email but cannot find it now. I will post up pictures of the intake though. After fuking around for past 20 minutes trying to get pic to go thru I go to advanced settings and see until i renew my gold membership its not going to let me post pictures, going to bed.

smitty,i love real world numbers,thanks for starting this thread.i am following it.

Thanks for posting this info.
Would like to see the hp/tq curves when you get to it.

Text me the pics and I will post if you like

Awesome testing thanks for sharing!

Cool, im heading to ph store to get this pos note 4 replaced then to shop to dyno. Later on i will renew my gold membership so i csn post b pics agsin, post up the few i sent you andbill comment, thanks, smitty

I can't wait for the further changes. Exhaust, cam, induction, and so on. You rarely see this kind of development being done. We can protest our theories all day long, but the proof is in the pudding . Thanks for sharing your project Smitty.

pics

The above pics, first one is port openings of Chinesium intake vs edelbrock victor, gimme fuel on here borrowed me the victor to try and he previously port matched it. I port matched the speedmaster and opened up the 2 tight ports i mentioned before, the writing you see on the face was widths/heights of ports the best i could measure them at pinch point. The second pic is bottom of the 4150 carb, dominator adapter and phenolic spacer. 3rd pic is dom sitting on Chinesium intake

It be cool, if you had an IAT sensor in the intake . I'd be willing to guess, the IAT's would be a fair amount cooler, with the carb, over the port injection. Especially when the weather heats up a bit in michigan. I remember reading a test where they did this on a Pontiac engine. Carb to port efi. The carb made about 20-25ish hp more if I recall, and the intake temps were quite a bit lower in the plenum, compared to the aftermarket port injection setup. It was like a 500ish hp build.

Great post thanks, I just dropped off my 548 at the shop to get dyno'd next week. 088 heads with 10:1 compression and using 454-R intake and 850 cfm carb. Looking forward to how it compares.

The carb-efi comparison on similar or same manifolds will be very interesting. Thanks as always for sharing!

again great job smitty...sorry for the phone deal the other day...I'll give you a call later Rob

One step forward, two steps back. Hp, afrs, tq went right to hell with dominator on one inch spacer, either manifold totally hates short spacer or motor loves the adapter and spacer under modified 4150. Maybe we created a mini tunnel ram with the adpater/spacer and motor loves it. Hp dropped from high 670s muffled to mid 650s AFTER alot of tuning , about 22 to 25 hp down at same afrs. 4150 was square jetted to side, took 8 jet sizes and 6 high speed bleed sizes to get afrs to match side to side within 1/2 point with dominatorl ;With open headers and same afrs at 6200 ish we are down 29 hp from 687 to 658 CF and air conditions identical as previous pulls at 1.035, surprisingly torque was identical at 639 ish but peak moved up to 5100 from 4900/5000. trying to borrow a 2" dominator spacer to test with or i will make one monday tuesday to re-test, i need to get 3" of spacer under dominator to see wtf is going on, will post when i have more, Smitty

So 29 hp loss from the modified 4150 carb to dominator?

On another note, these Canton power pans can go in Garbage, waste of 650 each, when dyno testing started oil pressure would dive from 75/80 psi to 40 ish and back several times from 6000 to 6700, pulled heads, opened up drain back holes, then oil press dipped LESS from 75/80 to 60/65, punched drain holes in lifter valley screens which I have used in the last 15 motors i built with no problems and with a extra quart in pan oil press twitches 5 psi around 6200/6400. I guess 8" deep pans suck for these rpms, never had this problem with my hardin 14 quart off shore pan, same motor at same rpms! On ANOTHER note, if it turns out this speedmaster intake loses 25+ hp when going down from 3" spacer to 1" spacer I think we may have found 25+ hp that tim full force may be missing with NO spacer on same intake!!!!

On my Edelbrock 454-R the website even days that it requires a 1" spacer to hit advertised levels. I believe if you buy a new one it actually comes with one. A pro-filer intake actually comes with a 1" spacer built in.

Question is will the spacer difference come from added plenum volume or extra effective runner length and flow straightening, or both.

I'm excited to see my 90 degree throttle body elbow and the 102 mm monoblade when he tests port injection on the chinesium intake

Yes, carb built by same guy, my partner on dyno, norm schenck. Carb also flowed within 10 cfm on flow bench to the 4150, about 1170/1180 cfm. Assuming there isnt a problem with this carb, its all in the intake spacers, once afrs are correct or same, fuel is atomized and as much air is supplied to motor as it needs it doesn't care what carb is on it, it does HOWEVER respond to plenum volume, air turning corners etc I dont have 4500 flange spacers laying around so I am trying to borrow one or will make one this week, If I piss around 2 or 3 hours making one Monday how ever it will move dynoing back a day as I do have a full time job and have jobs/customers to deal with at my business (my second job). I do have a customers monster truck deal sitting out back with a 528 ci ford with dominator on it, I will take a look and see IF it has a spacer under carb and how butchered up carb is as Id like to try more spacer and even a different dominator.

[QUOTE=Gimme Fuel;4528243]On my Edelbrock 454-R the website even days that it requires a 1" spacer to hit advertised levels. I believe if you buy a new one it actually comes with one. A pro-filer intake actually comes with a 1" spacer built in.

Question is will the spacer difference come from added plenum volume or extra effective runner length and flow straightening, or both.
The question that comes to mind if the hp goes to **** on a open plenum intake without a bunch of spacer carbed is it air flow path/plenum volume OR fuel distribution, will it have same problem with dry flow, would look pretty goofy on your boat if you had to have a 3" spacer under your 90 or would 90 add plenum volume??
You dont have another dom spacer do you ron? I have yours that was on the 454r , I can stack it on norms phenolic then stacjk a 3rd one, only problem is they should all be blended together or we are creating a new problem !

I might call the turd burglar rosebush in bay city and pay him the top dollar monday if he has something!

I bought two new 454 r intakes they dont come with a spacer

Well, now you know you need them lol

Great post. Keep it up.

Im excited to see what your boat runs too. I like the 30-33' step boats for making a real hot rod.

You're definitely on the right track about RPMs and operating range.

Gonna run the low compression until you get bored then boost them?

This is one of the best threads ever!!! :coolcowboy:

Smitty for President..............LOL................I wish he was closer to me, Id be over there heppin out.

Phragle, Your statement is correct, I was going to run one just didnt know what size.

Curious to see differences, I can say one thing... my Brodix intakes are WAY nicer then the pro comps, I wish I upgraded them at the time, was told back then by many it would not matter... after doing what I have now I think I will see good results... more cam, more compression, heads dialed in, things port matched and heads ported with accurate flow numbers... in almost excited to see results ...

Just the opening is a huge difference in quality [ATTACH=CONFIG]564696[/ATTACH]

Well, were only starting, i have a hard time believing it takes 6 or 8 jet sizes difference side to side to get afrs somewhat close w a 1" spacer vd 3" being okay square jetted. If this is true when i add 2 more inches under dominator the side jetted up should immediately go fat. I will NEVER even be running a carb on my boat but now i have to know the answer, ill run this fvker till its wore out to find out!

Damn.

Per our convo, I did look up the pan used on the 6200rpm 565 (4.375 stroke) that saw no oil psi issues and it is not the one you have, it was the #18-302
https://www.cantonracingproducts.com...MP-MARINE-PAN/

https://www.cantonracingproducts.com....php?id=18-302

Thats a nasty ass looking intake, my speedmaster looked muvh better box stock. I have a pic of it in my previous pics on here but i never figured out how to post them using phone . It says to click and drag but it only works on my home computer, i took a pic of it modified yesterday but thats with my old phone and havent got them transferred over yet