Some facts about head flow

[Plastermaster]

Well so far what I am seeing is that the only handicap with the T4 is availability. We have a very reputable source who started this thread debunking the T4 head myth, and we have examples like DRDs 10sec T4 built for cheap, and Jake has done the same thing on occasion. The T1 had one source for high HP heads for a good price through CB and a slew of headers, which again points to an availability issue and not an inherent problem with the T4 engine itself. There is always the line about it depends what you want to do with the engine as far as which one is best, and to an extent that is true, but only to the extent that finances dictate. In some cases the T4 will be more expensive for the same level of engine, only because of aftermarket parts. The aftermarket parts WILL come in time. The T4 is inherently longer living, better cooling, dominates the T1 in road racing, and is capable of holding its own in the 1/4 mile. The emphisis of the T4 has not been drag racing, but it can make a stand there as soon as there are enough of them participating.

In short the advantage of the T1 is cheap parts. If you want to call that an advantage, go right ahead!

Ron

[Steve Arndt]

, and we have examples like DRDs 10sec T4 built for cheap, and Jake has done the same thing on occasion.

Ron

Please explain.

[Plastermaster]

, and we have examples like DRDs 10sec T4 built for cheap, and Jake has done the same thing on occasion.

Ron

Please explain.

DRD built the engine pointed out on the Samba thread that led to this one. And, It was 12 sec not 10 sec, Still fast though!

Jakes engine I was refering to was built in a crunch for one of his customers race car (Mark Peeple). I do not remember the details but it was discussed on this forum. I might be wrong to say it was built cheaply. Jake stated that it was built from whatever he could scrounge from his shop. That might have been some precious parts.

"Jake the Great and Brent too!" Is the thread I was thinking of

Ron

[MASSIVE TYPE IV]

That engine was built 100% from used parts...

Non compatible lifters-
Used main, rod and cam bearings..

Used ported heads from my old 914 test engine..

We were going to replace the rings, but JE sent the wrong ones so I dug the old ones ofut of the dumpster and went for it with them...

186 HP at 7,000 RPM-

[Steve Arndt]

, and we have examples like DRDs 10sec T4 built for cheap, and Jake has done the same thing on occasion.

Ron

Please explain.

I knew that I didn't miss a post about a 10 second T4 here. Not until mine is running anyway...

[MASSIVE TYPE IV]

I also don't know where the 10 second engine is??? I never saw that post

[AlanU]

We have a very reputable source who started this thread debunking the T4 head myth, and we have examples like DRDs 10sec T4 built for cheap, and Jake has done the same thing on occasion.

The emphisis of the T4 has not been drag racing, but it can make a stand there as soon as there are enough of them participating.

In short the advantage of the T1 is cheap parts. If you want to call that an advantage, go right ahead!

Ron

I have yet seen FPS readings for every valve lift increment. The concern here isn't just misleading head flow numbers in CFM but the actual efficiency of the head overall.

If you took detailed pictures of the t4 head and got a Professional pro stock head porter to analyze the overal design of that head I think they'd frown. I am not talking about drag racing application but the efficiency aspect of the exhaust port design. I hardly expect a list of flow numbers debunking the inherent problem in the design of that t4 head.

I dont think the average t4 engine owner has 200hp at the flywheel. Many would probably bow down and be impressed to hear that sorta output from a t4. High dollar road race engines are impressive but I dont know the average joe having fat wallets to run such engines. The average t4 owner probably has decent very useable HP and torque. This is good for the person that suites his/her application.

So little examples to debunk the displacement to HP output in the t4 engine. why?? most guys do not have $$$$$$$$ road race prepped engines in the t4 platform. They have stockers with great reliability. Yes that head works but until an aftermarket head removes the horrible design the overall efficiency of that head will always cripple the t4. A bandaid cam can only do so much. If there wasn't some sort of a cripple there would be no need to manipulate a cam design.

It is apparent people just want to believe that the myth is debunk just by looking a a bunch of flow numbers. If that was indeed the case the ALL T4's would reap just as much HP per CC. This does not hold true so theres an obvious difference in efficiency of a t1 and t4 head.

Jake stresses that the t4 isn't all that for the 1/4 mile application. T4 and T1 all have their places in the auto world. I realize this and to say to 1 "reputable source" debunks the myth is so unrealistic.

[MASSIVE TYPE IV]

Look at a 911 engine- You'll see the same style of exhaust port.... It was designed to keep HEAT out of the head and in the exhaust.

Sure a Pro Stock porter would frown- But I don't give a damn!

The last road Race engine I saw that came from a Pro Stock builder had about everything in the world done WRONG to it- Two different worlds, don't compare them.

[R2.0]

I have yet seen FPS readings for every valve lift increment. The concern here isn't just misleading head flow numbers in CFM but the actual efficiency of the head overall.

Can we assume that the flow chart of the stock 1700 head in the first post isn't satisfactory? This whole argument has been revolving around a "lack" of published flow numbers. Now the numbers are published, and the argument is being reframed in terms of overall head efficiency?

I think you are trying to have it both ways here. You are complaining about how awful the stock T4 heads are, and how much work is required to get 200 HP out of them. But your baseline for comparison is an aftermarket head, the CB wedgeports. How does the stock T4 head compare against a stock T1 head? Likewise, how much porting work is required on these stock heads to get an engine to 200 hp? Or even to flow comparably?

You seem to think that everyone here is "drinking the Kool-Aid", and that 1 reputable source shouldn't be enough to debunk the myths. Where are the other reputable sources? You say you don't like the look of those head flow numbers, but a Pro Stock engine builder would tell us why. Where is he?

[MASSIVE TYPE IV]

And how many engines has the person creating the questions designed??

Sounds like someone has read too many posts on the CLF and too many books-

[Cohibra45]

Guys,

Again, I think AlanU is limiting his thinking to just HP#'s. It's an easy mistake. I use to make that one all the time. It's all you hear on the TV. All advertising is in the almighty HP#.

I would like to point out to AlanU that HP#'s are good to look at, but if you want to really impress me, you will have to show very good torque numbers down low and drivability. Len published numbers for a stock 1.7l with carbon on them for goodness sake. He just wanted to show that even the stock TIV put out more and better ratios than the 'stock' 1600 dp TI. To get high HP#'s out of any engine, a lot has to happen. A lot more than just head work. As Jake says, "It's all in the combination"!!! He has a racing 1.8l that revs to at least 8500rpm and makes very close to the 200 mark. I don't want to have to rev my engine nearly that high, do you? Jake is making me one of his 'SuperHero' engines and I can't wait. I will be giving out rides to everyone that wants one. The best way to get the word out is by 'seat of pants' !!!

Off the box now,

Kelly

[HAM Inc]

AlanU I have to plead ignorance with regard to your inquiry about FPS #'s at each lift value. Having been in this business most of my life (I ported my first pair of T1 heads in 1980 under my fathers supervision) I have never seen that acronym. Are you referring to LD (lift:diameter) ratios. which is a method used to determine the effeciency of the valve, port relationship? I listed flow #'s for the stock 1.7 head. What other info is required to calculate these FPS values? I.E valve head diameter, port cross section, etc.?

As for the awfulness of the T4 port designs, I have poured over many O.E. and aftermarket port shapes and flow values from a variety of air and watercooled heads over the years, and I can say that the O.E. T4 head measures up very well. I recently sent a silicone casting of one my effective chamber and port combos (a shape that Jake was happy with and performed well on his dyno) up to Panoz racings engine shop to have a CMM (Coordinate Mapping Machine) scan performed so I can save the shape on a computor disk for future use. They were VERY impressed with the fact that an O.E. head had such a sweet port arrangement.

I have 2 issues with the T4 ports.
1) The 1.8 and 2.0 914 intakes corkscrew as a means to enhance swirl. Modern designs abandoned this approach and race head designers go to great lengths to measure and eliminate swirl. This isn't a big deal on smaller displacement engines as the ports still flow very well. On larger displacement engines I straighten the port out a great deal and that seems to do the trick.
2)All T4 ex ports have a very short short side radius. This is a shortcoming, no doubt. But it is not the end of the world and the port still moves enough volume to have great velocity and it has no trouble delivering the magic 75% intake flow that has been proven effective in all N.A. engines.
And I'll point out that the overwhelming majority of production engines manufactured over the last 50 years have a very short short side ex. radius, (this is generally due to space limitations) including the small block Chevy, and it has managed to survive just fine. Check out a set of the famous O.E. "double hump" chevy heads some day and you'll see that the heads that helped make this engine a prolific race winner are "crippled" with a very similar short side radius, but with out the wonderful intake that the T4 has.
Also I will point out that Jake has produced 200HP using 2.0 914 castings that had very minor port work performed. It is true they were large displacement engines that didn't have to turn 7,000RPM's to make the power. But remember the issue at hand is can the O.E. T4 heads deliver the goods. Considering what I've seen, first hand, the fact that a simple 44 x 38 2.0 914 casting with minor port work is able to feed a 2.4l up to 200hp is impressive to say the least.

[MASSIVE TYPE IV]

I concur with everything Len stated...

Also, those heads on the 200 HP TIV 2.4L engine WERE NOT WELDED FOR PORT WORK!

I wanna see an 040 TI casting do that without any welding of the ports-

Have you done that Alan U????

If not, shut the hell up- (your just about to piss me off)

[R2.0]

AlanU I have to plead ignorance with regard to your inquiry about FPS #'s at each lift value.

Assuming he means feet/second, he is talking about air velocity. Actually the math is pretty simple:

Velocity (feet/second)=
Volume(Cubic Ft/Minute)*60 (seconds/minute)
-----------------------------------------------------
Area (Square Feet)

The area is valve lift times the circumference of the valve head, or pi*diameter.

Give me the intake and exhaust valve diameters, and I'll work up the numbers.

[Santas Brother]

Is it reasonable to compare a 40 year old production design
intended for passenger car use,as produced, to modern day
state of the art high spped race motor technology ?

Apples vs Oranges.
The application is entirely different.What constitutes a "good"
or "efficient" design for one,will not be adequate for the other.

I'm sure the guys who design the motors for Formula 1 would frown
at a state of the art Pro Stock,Top Fuel,or Nascar head.

If absolute "efficiency" was our number one criteria,we would
all be driving latmodel econoboxes.

If you took detailed pictures of the t4 head and got a Professional pro stock head porter to analyze the overal design of that head I think they'd frown. I am not talking about drag racing application but the efficiency aspect of the exhaust port design. I hardly expect a list of flow numbers debunking the inherent problem in the design of that t4 head.