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mgarblik · 07-15-2013, 03:55 PM

We are using a 1.85 ratio rocker arm with a round hole for a 1/2" push rod. It does take a bit of careful fitment to make sure you are not rubbing through the entire valvetrain event. We do have relatively low lobe lift of only .453.

dci · 07-15-2013, 05:54 PM

Fitting the pushrods will not be any more difficult than it is for other heads. I may find after test fitting that the pushrod hole needs to be drilled on an angle. I will not know that for sure until I try different ratio rockers on them though. This particular head we started with is set up for rocker studs. So trying a couple of different ratios will be pretty easy. There is plenty of material north and south. So if the hole needs elongated it will not be a problem.

Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the new DCI Ram Air 5 Heads !!!!!

Tom Vaught · 07-15-2013, 06:40 PM

Thanks Don!

Tom V.

dci · 07-22-2013, 07:04 PM

For everyone who has called and is waiting to see the flow numbers. I am anxious as well and will be getting them soon. The problem is customer work comes first, and with Norwalk as close as it is. I have my hands full with that and cannot seem to get the time to really dig into my head. I will tell you that I have done a preliminary test and the results are very promising. Something everyone needs to remember is that this is my street version of the head. What that means is the combustion chamber is deeper and less than optimum for air flow at all lifts @ 85 cc's. Also this is a 2.200 valve with a 45 degree seat and I have these test head's set up for a 4.18 bore size. I also only cut the bowl area for a 90 % throat to keep the velocity up. I am testing these on a 4.200 test fixture because my next smallest fixture is 4.100. I am crowding it towards the wall though to try and simulate a smaller bore.

With all this taken into consideration. What do you think the heads will flow? Give me a number for .400",.600", and .800" of lift. Just trying to create a little fun until I get the final results. I will have some solid info before Norwalk and I will have a head there for everyone to look at. I'll give you a small hint just for a barometer. At .300 my initial test number at 28" was 236 cfm. This number will most likely change once I get the valve job were the head likes it. It may go up, or it may go down. I will not know that until we do some more testing. I also know without a doubt, that the smaller chambers will produce better numbers all the way through. My prototype model showed us that with a 50 cc chamber.

Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the new DCI Ram Air 5 Heads !!!!!

dci · 07-26-2013, 02:36 PM

Well I was finally able to get to play with head some more. Keep in mind like I stated earlier that this is on a 4.200 test fixture with a 2.200 intake valve. This is pretty much as cast except with a bowl clean up like you would see from Edelbrock, and the pushrod tube narrowed and smoothed. This head will also bolt onto a factory stock block with a 4.150 or bigger bore and attain these numbers. I actually had the edge of the combustion chamber out over the edge of the test fixture. Meaning it was not even with the bore, but actually on the negative side about .030". Flow test were done at 28" of water and are not corrected. I have not had time to do the exhaust side yet. So all I have for now are the intake numbers.

Inches of lift CFM

.100 89
.200 168
.300 240
.400 298
.500 338
.600 367
.700 384
.800 400
.900 416

My test model flowed a little better from .300 on up, but it was a small chamber and did not shroud the valves much if any. Although not quite as good as my test model. I am very pleased with the results for as little time as I have had to spend with it. I can't wait to start porting it!!!!!!

Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the new DCI Ram Air 5 Heads !!!!!

RAIV-Z · 07-26-2013, 03:03 PM

Quote:

Originally Posted by dci

Well I was finally able to get to play with head some more. Keep in mind like I stated earlier that this is on a 4.200 test fixture with a 2.200 intake valve. This is pretty much as cast except with a bowl clean up like you would see from Edelbrock, and the pushrod tube narrowed and smoothed. This head will also bolt onto a factory stock block with a 4.150 or bigger bore and attain these numbers. I actually had the edge of the combustion chamber out over the edge of the test fixture. Meaning it was not even with the bore, but actually on the negative side about .030". Flow test were done at 28" of water and are not corrected. I have not had time to do the exhaust side yet. So all I have for now are the intake numbers.

Inches of lift CFM

.100 89
.200 168
.300 240
.400 298
.500 338
.600 367
.700 384
.800 400
.900 416

My test model flowed a little better from .300 on up, but it was a small chamber and did not shroud the valves much if any. Although not quite as good as my test model. I am very pleased with the results for as little time as I have had to spend with it. I can't wait to start porting it!!!!!!

Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the new DCI Ram Air 5 Heads !!!!!

Nice numbers Don!

Tom Vaught · 07-26-2013, 04:02 PM

Typical .750 lift camshaft, (for the average guy - Not the 1" lift 'Big Richard" racers type camshaft would still get you real close to a 390 cfm head. THANKS DON!

Using Mike L's 2.4 multiplier (if you do it right) 936 HP Naturally Aspirated.

Tom Vaught

dci · 02:13 PM

I was just looking back at the HPP article on my Tiger heads when we first introduced them to the public. So I thought I would post the numbers from that article of the flow test we done at that time for comparison to my new head. When I designed the Tiger heads, I set them up to work on a factory block with a 4.25 bore and that is what we flow tested them on for the article. Keep in mind to that they had a larger intake valve in them than my new V heads do. For the article we had a 2.250 intake valve for the HPP test. I am only showing the intake numbers because I do not have any numbers for the exhaust yet for my V heads.

Tigers

.100 76.5
.200 144.5
.300 208
.400 267
.500 316
.600 358.2
.700 388
.800 412
.900 422

Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the new DCI Ram Air 5 Heads !!!!!

dci · 07-27-2013, 02:35 PM

Forgot to mention the average flow for both head as well. DCI Tiger's 288 avg., DCI V's 300 avg.

Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the new DCI Ram Air 5 Heads !!!!!

johnta1 · 07-27-2013, 04:04 PM

Sounds like an awesome flowing head!

Using Craig's HO Racing area under the curve calculator, I get 265 cfm for your Tiger head and 277 cfm for the RAV head.

Still more than the Tiger.

Link to Craig's calculator on my site that I added the 2 head info and expanded the cam lift input to .900 lift.

Area Under Curve Calc

estep455 · 07-28-2013, 08:53 AM

awesome Don! cant wait!

paris pugliese · 07-30-2013, 12:56 AM

Any numbers with a fully ported one

dci · 07-30-2013, 10:33 AM

I am going to try to get a port ported before Norwalk if I can get the time. The question is,Do I keep it at a 2.200 valve or open it up to 2.250? The racer in me want's to go big, but my common sense say's to go slow and gather data LOL. Maybe I'll do a little porting to the 2.200 valve port and do a port with a 2.250 valve. We'll see!!!! I need to get some numbers on the exhaust hopefully before Norwalk too.

Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the new DCI Ram Air 5 Heads !!!!!

paris pugliese · 07-30-2013, 10:58 AM

If you port one with a 2.200 valve .it is easy to put that 2.250 valve job on it .not so easy the other way Iam a cylinder head junky

slowbird · 07-30-2013, 11:04 AM

Go big

ho428 · 07-30-2013, 01:04 PM

Make a good street head first.

Stan Weiss · 07-30-2013, 01:59 PM

Very nice lower lift flow. I would guess some of that is the result of the smaller valve. Can you say what the csa and velocity of each was? The Green line is the RAV and the Blue line is the Tiger Intake (Cyan line is the Tiger exhaust).

Stan

dci · 07-30-2013, 03:29 PM

Thanks Stan,
Nice graph of the two heads.

If I get time I am going to port the one I have done now and also do a port with a 2.250 valve too. Who needs sleep, everyone tells me it's over rated anyway LOL.

Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the new DCI Ram Air 5 Heads !!!!!

10second70GP · 07-30-2013, 03:56 PM

Quote:

Originally Posted by 428RA4

Pontiac made an experimental Tunnel Port Hemi head. IF you want to sell to the race guys, this is what should be built in my opinion.

I would be all over those in a heart beat .

Skip Fix · 07-30-2013, 07:05 PM

For looking at larger ratio rockers you might look at Crower's 1.8 offset trunnion BBC one. Makes it easier to get a 1.8 on a "regular" head especially if you didn't grind the hole right on an iron head.. Jim Robertson has a couple of my extras for mock up.
Might make hole placement easier for you.

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