some 4150/4500 dyno info
 

548 ci

Vic Jr 4150 intake

AFR 305 heads

2 inch open spacer / adapter on all pulls

1st pull Pro Systems 4150

2nd pull Pro Systems 4150

3rd pull antique Holley 4500 pre Dominator (nascar)

4th overlay pull 2/3

Round 2 different intake and more modern carb. Posted one at a time seems a little clearer

Vic Jr 4500 Dominator flange

Pull 1 4500 Quick Fuel ( no more antique Holley)

No spacer

1 inch HVH Super Sucker

2 inch HVH SS

1 inch HVH SS, 34 degrees vs 36 degree timing overlay. 34 is the one that made more power

Notice the first post with all the pulls grouped together was with a 4150 flange Vic Jr with two different carbs. The individual posts were done with the 4500 flange. I guess I could've posted it better, sorry. Hopefully it helps someone.

Specs on the 4150 carb. I'm sure jets and possibly bleeds are not what is on the sheet. Just posted it for the basics.

Looks like you need a bigger intake.

Vic 454R w/Dom flange ?

Yes. The pulls that I posted individually were all Dom flange

The parts swapping and testing budget is exhausted. That's like 8 pulls using 2 intakes, 3 carbs and 3 spacers, plus misc adjusting and fixing while on the dyno and they are still going back on AGAIN- I cant take anymore. There is one more type of spacer I'd like to try when they go back on, but someone would have to provide one to test or make one on a fancy 3d printer.

Call Dave at HRE. His spacers are the best. I think a 2 in one spacer with anti-reversion plate at the top will give you the best results. With the short intake runners and a small head I'm sure the sign wave is slamming the bottom of the booster and fuel is falling out of suspension. That's why the Dominator with the 2" spacer did so much better.

Speak your peace, maybe someone has one you can borrow.

Possibly something along the lines of what black Baja is referring to. Actually someone posted a tech article recently that mentioned a 4 hole spacer at the top to essentially lengthen the throttle bores for a better signal transitioning to an open spacer to allow the fuel to curve towards the runners is how it was described iirc.

[QUOTE=Black Baja;4439380]Call Dave at HRE. His spacers are the best. I think a 2 in one spacer with anti-reversion plate at the top will give you the best results. With the short intake runners and a small head I'm sure the sign wave is slamming the bottom of the booster and fuel is falling out of suspension. That's why the Dominator with the 2" spacer did so much better.[/QUOTE

Well put. I always respect your input.

The purpose of a 4 hole spacer is to protect the booster from the pulse that travels back up the intake port when the intake valve closes. If that pulse slams the booster you are in trouble. Fuel turns into a puddle in the bottom of the intake power goes down and detonation goes up. You really need a properly designed spacer to get the job done correctly. The HVH spacer looks cool but doesn't protect the booster.

Thanks for posting. You have a solid 700 plus hp engine at well desired rpm and that's great. Good job. Did you use a custom grind cam? Certainly seems to work well with given combo.

Here is the quote from the Teague tech article that had me interested.

"Try the World Products Merlin X to accommodate a Holley 4500 series Dominator carburetor. The manifold works well out of the box and has brass inserts in the water passages to protect from corrosion. Select a two-circuit 1050 CFM carburetor. Three-circuit carburetors run rich in the midrange. Under the carburetor, install two 1-inch spacers. The top spacer should be a four-hole design, which lengthens the carburetor venturi and improves the booster signal.

This improved influence on the carburetor boosters will improve throttle response with the big carburetor. The spacer next to the intake manifold should be a cloverleaf design that improves the flow transition from the fourhole spacer to the intake manifold plenum..."

I saw that you and possibly someone else were discussing 4150/4500 choices and I thought some of this info might be helpful.

Ya I was glad to see you posted. Looks like the engine liked the 1" spacer torque wise. Interesting to see your results.

Yes, but on his 650 and up NA Dom powered engines he ran 2" HVH Super Sucker spacers.

Well, I've tried the 2 inch HVH then. This is a Dom package he's referring to in the above.

Tried sending u a pm but your full
John

What was the compression ratio and general cam spec's on your engine? Nice post by the way, lots of great info!

We were supposed to do a head to head comparison of 9.3 vs 9.7-8 but issues beyond our control prevented that. I should have that info when we're done but won't be able to use it for decision making. The first group of pulls with the 4150 intake were 9.7. The second group of pulls with the 4500 intake are 9.3. Cam is roughly 243/654.

Just an FYI the Pro Comp spacer on the same motor/ same dyno/ same day made the same power as the HVH spacer.

Yes, and it probably came with a free piece of a ham sandwich, if you ground it out.

That costs xtra...

You think your getting a VIP invite to cam room. Some go to their grave with those secrets. Ha... Don't worry I didn't get the magic numbers either. Needless to say it is a great thread with good info regardless. All I can say is going to dyno room with a truck full of goodies to try is a riot.

I gave the general specs he asked for. It's a shame we didn't get to do the head to head comparo on the half point of comp. But we had some obstacles crop up that prevented it.

I agree that would have been interesting. I know some say it makes a difference and others say no noticeable difference. I'm in the "it matters" camp. If time was on my side I would like to get my new engines on the dyno and see exactly what they make. I was told 650-675 hp. Either way, great info- thanks for sharing.

I will get to know the difference in the half point when they go back on. Unfortunately it will be too late then to use the info to make a decision. The engine builder swears half a point will be unnoticeable, or within the standard range of variance from engine to engine/ pull to pull. He is in the "doesn't matter" camp.

Thanks for sharing the info BCK.

As far as compression goes,
My thoughts are, if everything is equal, higher compression is typically going outperform lower compression. But, things are often not equal. Rarely is a combo absolutely perfect by design, and I myself, would not trade off static compression, for cylinder head flow, cam timing, intake tuning, exhaust tuning, etc. Also, jacking up the static compression, was the key to making power decades ago, when guys typically had factory heads to work with, limited camshaft designs, limited induction designs, and so on. Its a no brainer that a 540ci with 9:1 static , afr cnc heads, good induction and exhaust, would walk all over a 10:1 , factory headed, crappy cam combo build.

An example I find interesting, is some guys will completely tear an engine apart, to get 1/4 to 1/2 point of static on their build, and then install a set of "average" marine exhaust manifolds, or a general induction combo. Often discussed are cams, heads, carbs, intakes, and rarely, is exhaust design a topic in our group. Most tend to just assume that if its not a stock iron merc manifold, its fine for about any engine, any power level, etc.

It be interesting to see a series of tests like BCK did with his induction, with a series of different exhaust styles. Manifolds vs headers, header size, length, collector length, and so on. I have a series of dyno tests here from a buddy, who just from swapping from one style of CMI's, to another, saw a difference of over 20 peak HP, and 15 ft lbs of peak torque. This was on a 750ish hp N/A engine. While 20hp isn't a ton, thats just an example of two similiar, but different header styles. I'd bet the difference would have been much greater, if comparing a set of 2.25" tuned for the engine headers, and a set of basic GILS, stainless marine, imco, etc, would have been compared back to back.

I've been told just using the cat pans that I have will make the engines different from one another because of the extra room for the oil to sling off the crank on the one engine. We will hopefully be testing the exhaust if it is at all possible to fit it on the dyno, so hopefully we'll get some more info to share at least about CMI big tubes vs automotive style. M/T have your friend that needs the t-stat give me a part # if he has them apart. I have someone that claims he can get them from the manufacturer, but needs a part # or any other info.

All things being equal .5 point of compression will yield 1.5-2% more power. So 10-15hp in your case.

The Otto cycle is well known and has been mathematically modeled. The torque potential can be calculated from the engine specs and derived from BMEP. The only tricky part is when using high overlap cams and tuned exhaust systems that can improve scavenging and create higher than 100% volumetric efficiencies at some engine speeds.

That's about what I thought. It wasn't cheap to get a 15hp gain on these motors so I wouldn't be thrilled about losing 15 by being down .5 as small as it sounds. I can't believe I didn't just buy blowers.

Yeah people say 15hp isn't significant, but 15 here and 15 there adds up!

Sounds like there may be some HP in controlling the oil in your pan depending on your current setup.

I missed something(s) in all of this.

Why all this parts testing and now compression change going down ? The starting out 670hp was really pretty good and the ending 700hp is really good.

We intended to check the best combo (700hp) at both compression levels to see how much of a difference there was. If significant we'd set them both up at 9.7 or if running the 4150 at a slightly higher compression gave power numbers I was satisfied with we would not have swapped intakes / carbs and saved me some cash. We had multiple setbacks on the dyno that made that impossible.

The engines were originally going in a different boat that needed the cat pans. There are the usual trap doors and such in the pans but the kickouts are on opposite sides of each pan. I was told that alone can have a noticeable effect