Some facts about head flow

[John W. Kelly]

VW Chuck, the "weak link" is lack of R&D. How many gurus have poked around at the t1? I'll bet 10 (or more) times as many as the t4. Sounds like Raby is probably not working with the benefit of previous tuners who's findings he can draw from. I can port a fairly good running t1 head, however I did very liitle if any of the initial research. I have so much information avalible to help me (done by others). I don't see this bounty of info avalible for the t4. Yet.

[MASSIVE TYPE IV]

Yes, a Lot of what we do is done for the first time and done that way on purpose.

I have always chosen to create the footprint instead of stepping in someone elses..

As the engines gain popularity R&D soars and we find all sorts of new things....

Len and I are not drag racers, and have little desire to create engines with that type of powerband.

[Plastermaster]

I revisited the samba thread and found it locked. I had not looked at it in a few days. I noticed in the posts that were added since my last visit, some addional myths about the T4 head. The myth that they are expensive. I have seen $1,500 as a standard for top notch head work for the T1 factory head. This head will put you in the 180HP and up catagory and is often not recomended as a "street head" due to drivability. That is better achieved with smaller valve head, that will cost less but will get you more like 150-160 HP.

Aftermarket heads: From what I gather, CB makes a nice head for a good price that cools pretty good too. This has been available for a few years now since they have improved thier earlier design. The original 044 was not as good at taking the heat. As for other after market heads, there are some that flow and make good power, problem is they forgot the fins. Then there is another one with fins but the STF has pages on them so I will not elaborate on those muthas. LOL

For cheap factory heads: Show me a T1 head that when given $350 of P&P will out perform a T4 head with the same price tag. Now slap those heads on a Junk yard T4 core engine and you will have many miles of cheap power compared to a 1600 T1 with the same head work. Or, put some bigger jugs on it, and compare it to the T1 counterpart, like a 1776 or 1915. Just because the industry isn't saturated with shops turning out cheap T4s doesn't mean it cannot be done.


I just got home from work, and had to spew this because I was thinking about it today. I have not spent hours double checking all my numbers or collecting links to my sources of information, but if my memory isn't too far gone I should be pretty close.
Ron

[Eddie Brown]

Good points Ron. Pretty soon I'll be in the market for a set of heads from Len for my turbo 2258 for my 914. Obviously great results can be gained from experienced workmanship. As we all know from driving T4's(although sometimes taken for granted) is that they possess natural torque. When the heads and exhaust can be made to be efficient, the motor is able to explore its true potential.

I could imagine how much nicer my 1911 would run had the heads been rebuilt with better specs for my given displacement and exhaust system. Yet it still surprises people on how it pulls from idle.

[Steve Arndt]

DRD,
Are you still up for flowing my1.7 core based 48x40 six stud heads from Alfred Knuf? I can quadruple box one for safety sake during shipping. I'm quite confident they are re over 200 CMF at 28" since 2.3 liter engines w/ the same heads and 10:1 make 230 horsepower.
Steve

[914 Ghost]

In case the mandanimal comes here to lurk, a few things not mentioned (didn't see it anyway) that contribute to why the comparison is ridiculous, and WHY his main point (T4 head cracking blah blah) are basically not thought out:
*The majority of T4's spent life in STOCK form pushing a 4000lb friggen BUS, fuel injected with a CRAPPY cam designed to overheat the exhaust to meet emissions. Of course some seats droppped out!
---Please please!! Put a T1 to the same test and see how long it lasts. Put the smog equip and air conditioning on it, and see how long it pushes a 77 Westy down the road- and take it to the emissions place, see what marks it gets.
In 17 years of working on VW's AND Porsche I have never ever seen a T4 head problem in a 914 no matter how abused. Tear a 130,ooo mile 914 engine down and you'll find pristine bearings and almost NO wear, hone marks in cylinders. 130k on a bug? Doesn't look great inside usually.
The argument: VW quit making a BETTER engine for a worse one and never ever realized the mistake. Uhhmm.. yeah.

end rant, whats the topic again?


Bob O
"used to HATE the T4"

[John W. Kelly]

Good points Bob. I have seen a valve seat problem (only one though) but I don't know the details of "why". The fellow sold me the car (914) because it "didn't run very well". Number 1 intake seat had dropped. I've never had any other such problems on my t4's. I also have 3 buses.

[John W. Kelly]

Good points Bob. I have seen a valve seat problem (only one though) but I don't know the details of "why". The fellow sold me the car (914) because it "didn't run very well". Number 1 intake seat had dropped. I've never had any other such problems on my t4's. I also have 3 buses.

[HAM Inc]

All T4 heads that come through my shop recieve all new valve seats. The heads are placed in my casting oven with the chambers down and heated to 400*F. On average about 25% of the seats just fall out from gravity alone, the overwhelming majority of these are intakes. A few more will drop out when a steel dowel is rattled around in the I.D. Most require welding to remove and are not at risk of dropping. I replace them all as a matter of routine because the at risk ones seem to fall out after being cut or ground and recieving new springs.

The 400*F point seems to be the critical point. All of you with O.E. seats keep that in mind as you watch your head temps.

[AlanU]

DRD,
Are you still up for flowing my1.7 core based 48x40 six stud heads from Alfred Knuf? I can quadruple box one for safety sake during shipping. I'm quite confident they are re over 200 CMF at 28" since 2.3 liter engines w/ the same heads and 10:1 make 230 horsepower.
Steve

Only 200 cfm?

Steve you must think "out of the box" and think about the port velocity as well as CFM numbers.

CFM numbers is a great selling tactic for the consumer that has be trained to believe its the determining factor of performance.

The people that like t1 and t4 "usually" use these engines for totally different applications.

Commonly I'll see people suggesting that the type 4 is the perfect daily driver motor. I'm just very curious to see how many people use a beetle as a daily driver in this day and age. I can see how appealing the flat torque curve of a type 4 would be in such a daily driver or for certain racing applications.

LEN, I'd be interested in seeing the head flow numbers of a reworked intake on a type 4 aswell as the FPS readings on every increment of valve lift. If I was to go t4 I'd be more interested in the lines of 1/4 mile application along with street driving.

Most importantly what is the cost of fully reworked t4 heads?? This is where the T4 has to improve on. If there was an aftermarket head with cfm and fps to match I'd see more t1 guys converting. At this point in time longevity with a flat torque curve is what a t4 has. To make alot of HP per cc of displacement is still an extremely expensive engine build in a t4.

The amount of driving I now do with my 65 beetle doesn't warrant a t4. I use to drive my car as a daily driver. I can get into the 11's on pumpgas with my 2332 in a steel/glass complete car. My intake ports are only around 72cc's so my heads are reaching in the lines of sonic choke. Opening up my heads more would reap more HP.

I think the appeal to the t1 is cost and usually the type of application of use. $$ for $$ the t1 is the best for HP per CC of displacement in hotstreet/drag racing application.

I don't think it takes Einstein to figure out the t4 is a superior engine to the t1 simply because the engineering is more modern

I guess in strength department the t4 has improved from the little brother t1. Being more modern isn't an indication of superiority. Thats almost like saying an 1980's engineered electronic feedback caburetor with a single wire 02 sensor is superior to a traditional oldschool jet metered carb. Newer technology doens't neccessarily mean superior or better.

Im a mechanic by trade and if you work on some of the new cars these days you wouldn't be stating the word superiority. Look at the new VW's. They are high on the list in the lemon book.

[Steve Arndt]

Alan,
You are correct.
Why do you think I went from 44x37 heads to 40x35 heads on my baja? Why do you think I spent more money on my (infinite angle) valve job than I did on my porting?

Another thing, sticking velocity probes in the port do help you gather information, but your engine shouldn't be running steady state unless you are tractor pulling or climing an infinite long grade at steady speed. Probing for pressure and velocity is great, but your engine isn't a steady state device. Pulse flow isn't constant flow.


Flow quality, not quantity.

[MASSIVE TYPE IV]

Commonly I'll see people suggesting that the type 4 is the perfect daily driver motor. I'm just very curious to see how many people use a beetle as a daily driver in this day and age

Quite a few, more than you would expect. I have some customers that average 20K miles a year on their beetle with my engine in a bug.... One of the more eccentrics of this group built an entire beetle body from stainless steel from scratch and has vowed to never buy another car again!

What we do here appeals to more than just "beetle" owners... We have a heavy concentration of 356 owners, bus owners and 912E owners in our ranks as daily drivers....

Hell, my 912E is a 1976 and its the newest car I own- I have driven it almost 85K since September 12th 2002 when I installed it's "Sweep the floor" used parts engine......My problem with the TI was that it seemed to never hold adjustments and was plagued by stupid simple things that called for the decklid to be opened every weekend for some reason- That is far from the case with a TIV, and something that NO OUTSIDER from the TIV world can comprehend until they experience it.

Hell the 3 liter has logged near 8,000 miles since it was installed this past March- I haven't even synched the carbs or changed the oil since it was installed. In our record setting heat so far this summer I have driven this car in temps well over 100 degrees and watched the head temps reside at 275-300 and oil temps no more than 230, even with a tiny 48 plate external cooler, with NO FAN. Yep, I wanna see a TI with a 4.137" piston accomplish that feat!

Making the beetle an easier more fun to drive "Daily driver" has been my goal the entire time, thats why we created the A/C brackets and etc for the DTM and are primarily working with EFI for all our current and future MassIVe engines.

[Cohibra45]

Jake,

Speaking of A/C brackets for your DTM, I am thinking that I might have to get one for my Ghia. I had to come back to the beach to cool down a bit. I just spent the last three weeks in N.C. (visited Asheville a couple of times), and the heat was too much. Much cooler down here in Florida near the coast with the sea breeze.

Almost made the decision to drop by on the way back down. Maybe next time when the weather changes.

Kelly

[HAM Inc]

Yep, mixture quality is much more important than volume. But don't forget that the single most effective way to ensure good mixture quality is to maintain high port velocity.

The flow through a port is never steady state, even if the RPM's are. Measuring velocity is an exellent way to predict how a head will perform on the vehicle. But at what lift values does one measure the velocity? The answer depends on the application. On a high speed, high compression race engine I couldn't care less what the intake flows below .100" lift. On a typical street engine I'm more concerned with what it flows under .300 lift.

Interpreting flow data is a skill that takes experience and without these skills the flow data is useless. This is one reason I don't go out of my way to publish my flow data. Most folks don't know what they're looking at (though many THINK they do). They tend to focus on the largest #.

And then I find myself defending data from heads that over the years have won races and competitions at various levels (up to the S.C.C.A. National level) to some cat that's read a few articles (and maybe even a book or two) and thinks he's got it figured it out. And I really just don't feel like dealing with that anymore.

I think most porters are perfectly capable of carving a huge port that will flow huge #'s. But once again how is the port velocity? How balanced are the ports and how applicable is the port design to the intended use?

Rare is the STREET or A/X engine that needs more than 200cfm to kick but with, even large displacement engines that wind to 6500rpms. A 42mm intake will flow 200cfm if the port, seat, and valve are prepped properly. It is easier, and therefore cheaper, to achieve 200cfm with a 44mm valve.

[MASSIVE TYPE IV]

And the valve is lighter!