Looking to make some more power, welcoming ideas/advice

[BobbyB]

Good rule of thumb is 2% per point. Given that, 0.3% increase in compression would be worth 0.6% power increase. Do with that info what you wish and see if it's worth it in your case. If it's already apart, maybe. If you'd have to pull it apart to make the change, there would be better ways to make a bigger difference.

Thanks for the info, that is not worth the effort. The new cam and my new ignition system will have to be good enough, which I am sure they will be. The new ignition has already made a nice noticeable difference down low/part throttle. My current cam is "way wrong", so I am excited to see what this new one does.

Please keep us posted on your progress with your new set up. How will you determine what you want your ignition timing curve to be? Desk Top Dyno can suggest an ignition curve if you input your parameters, but I don't know how close to optimum it is. Good luck, stay safe & have fun!

[GRTfast]

Good rule of thumb is 2% per point. Given that, 0.3% increase in compression would be worth 0.6% power increase. Do with that info what you wish and see if it's worth it in your case. If it's already apart, maybe. If you'd have to pull it apart to make the change, there would be better ways to make a bigger difference.

Thanks for the info, that is not worth the effort. The new cam and my new ignition system will have to be good enough, which I am sure they will be. The new ignition has already made a nice noticeable difference down low/part throttle. My current cam is "way wrong", so I am excited to see what this new one does.

Please keep us posted on your progress with your new set up. How will you determine what you want your ignition timing curve to be? Desk Top Dyno can suggest an ignition curve if you input your parameters, but I don't know how close to optimum it is. Good luck, stay safe & have fun!

Well I’d expect the all in value to be in the 38-40 range. Once i have the new cam in, I’ll play with the all in point and initial timing to see what it will take without pre-ignition. Basically I’ll just play with it. I’ve got a pretty sensitive ear and “butt dyno”, I did a lot of racing, engine development and test driving at a high level In my shifterkart racing era.

[GRTfast]

Ok, let me preface this post with---- I feel stupid.

I run one of those vintage cadillac style air filter housings on my engine. The car is scratch built with styling somewhere between rat rod, old school lake hot rods, ww2 aircraft, and the Munster hotrod, so the housing fits the bill style wise.

I went for a test drive earlier today without the air filter on the car and it felt noticeably livelier. In all the years of having the car so far, I've never done this at full throttle, just a few cruises around the neighborhood.

The filter itself is a 13.25 diameter 4 inch tall element which is plenty big, but the cross sectional area of the two openings in the filter housing only add up to about 7 in^2

My carb has four 1.75" bores which add up to about 9.6 in^2

Have I been choking my engine this whole time?

Pic of the car for reference

[Dave Koehler]

The increased noise will play a part in how lively it seems.

[GRTfast]

The increased noise will play a part in how lively it seems.

I tend to agree, but this was significant.

The left exhaust outlet is 2-3 feet from my ear. I'm pretty sure I am not hearing the intake..

I think I am pretty good at separating the sound from the feeling, as the car doesn't feel much different from mufflers to open headers, and in that case the sound is obviously way different.

Has anyone on here played with air filter housing inlet size vs carb size to see what the effects are?

[BILL-C]

It's time to schedule some chassis dyno time!

[GRTfast]

It's time to schedule some chassis dyno time!

Yes I know that is the ultimate answer.

[MadBill]

Just for reference, lots of bumper-mounted cold air intakes use two 4" hoses. (5" for the factory Ford Thunderbolt and some others), which would be 25²" and 40²" respectively... In his Power With Economy book, David Vizard describes how to test for air intake restriction:

• Get ~15' of small diameter clear tubing, such as used for aquariums.

• Form it into a 'U' shape and tape it to a yardstick, open end up to above the zero inch mark and hang the apparatus from the mirror or whatever to permit viewing as you drive.

• Fill it with colored water to the 18" mark.

• Find a way to connect the other end of the tube to the interior of the aircleaner inboard of the filter.

You now have a 'U' tube manometer and can observe the air cleaner restriction as you accelerate at full throttle to peak revs. Vizard recommends no more than 1.5" H2O at peak RPM.

Bring a towel, I suspect it's going to exceed 36" H2O.

PS: It sounds like the restriction may be enough to throw off the fuel mixture, acting like a partially closed choke.

PS2: Your filter's plenty big. Here's K&N's formula for filter sizing:
A = (CID x RPM)/20839 where A is filter area (diameter x pi x height minus 3/4" to allow for the height of the seals)
e.g. (350" x 6,000 RPM)/20839 = 100 ²". 14" x 3.14 x 2.27" = 100²". add 0.75" for seals, thus a 14" x 3" filter.
PS3: If you can't gut the housing to reduce restriction, your could retain most of the antique vibe by incorporating a K & N X Stream filter top.

[Calypso]

You could get a g-force meter for your smartphone and do quick acceleration tests with and without air cleaner. Some of them have peak-and-hold features, so you don't need to watch while driving.

[Adger Smith]

The falling on the face bothers me..
I have seen and heard of a huge amount of power gain getting rid of the HEI module or dist.
The Chinese electronics in those modules are all over the place.
Dist first.
Then maybe a slightly bigger header tube.
Get cam with closer to .600- .650 lift. The heads are not flowing with that .540 ish lift cam.
You have a cam that has an ex side that is oversized and then small tube headers. Screams mismatch to me.
I have seen those intake manifolds make big power at EMC.

[GRTfast]

The falling on the face bothers me..
I have seen and heard of a huge amount of power gain getting rid of the HEI module or dist.
The Chinese electronics in those modules are all over the place.
Dist first.
Then maybe a slightly bigger header tube.
Get cam with closer to .600- .650 lift. The heads are not flowing with that .540 ish lift cam.
You have a cam that has an ex side that is oversized and then small tube headers. Screams mismatch to me.
I have seen those intake manifolds make big power at EMC.

New cam is ordered from Camking.

New distributor is already in the car, it’s the programmable HEI replacement. All parts sourced in the US, spark test they perform on their site is rock solid to 8200 rpm. Timing appears to be super stable via observation through their live app and confirmed with timing light.

[GRTfast]

Just for reference, lots of bumper-mounted cold air intakes use two 4" hoses. (5" for the factory Ford Thunderbolt and some others), which would be 25²" and 40²" respectively... In his Power With Economy book, David Vizard describes how to test for air intake restriction:

• Get ~15' of small diameter clear tubing, such as used for aquariums.

• Form it into a 'U' shape and tape it to a yardstick, open end up to above the zero inch mark and hang the apparatus from the mirror or whatever to permit viewing as you drive.

• Fill it with colored water to the 18" mark.

• Find a way to connect the other end of the tube to the interior of the aircleaner inboard of the filter.

You now have a 'U' tube manometer and can observe the air cleaner restriction as you accelerate at full throttle to peak revs. Vizard recommends no more than 1.5" H2O at peak RPM.

Bring a towel, I suspect it's going to exceed 36" H2O.

PS: It sounds like the restriction may be enough to throw off the fuel mixture, acting like a partially closed choke.

PS2: Your filter's plenty big. Here's K&N's formula for filter sizing:
A = (CID x RPM)/20839 where A is filter area (diameter x pi x height minus 3/4" to allow for the height of the seals)
e.g. (350" x 6,000 RPM)/20839 = 100 ²". 14" x 3.14 x 2.27" = 100²". add 0.75" for seals, thus a 14" x 3" filter.
PS3: If you can't gut the housing to reduce restriction, your could retain most of the antique vibe by incorporating a K & N X Stream filter top.

Thanks. I’m going to put some large holes in that front part of the filter housing. Get the area up around 30 in^2

[vortecpro]

I have made 508 hp with bowl ported peanut port BBC heads !
Your rectangular port heads and that Cam are a terrible mismatch!

YES, you know I like a peanut port build!

[GRTfast]

Ok, so I got my new cam from Mike, and the install went smoothly. Just took it on a test drive, impressions are as follows:

Idles a tiny bit smoother, but still nice and lumpy. Seems a little quieter.

2nd and 3rd gear low rpm cruising (through the neighborhood) in the 1400-1700 RPM range is noticeably smoother, much less tendency to buck.

Pulls harder all the way through the rev range, but especially up beyond the torque peak. I set my rev limiter to 6600 RPM and it pulled there no problem, seemed like it was laying over a tiny bit as I approached it though. That's the same way it used to feel at 6000 with the old cam. Now at 6000 it's pulling like a GD freight train. Mike said that this cam's HP peak is 6000, so it makes sense.

Happy.

[BobbyB]

Glad to hear it! I was hoping you would post an update on that beast.

By the way, do you own a draggy? I think you will find it well worth $150.00. Mine is showing me what my butt dyno didn't know.