Anyone have experience with an ABA running 42x35mm valves?

[nextproject]

AND a seriously ported cylinder head and short ram intake manifold?

Seems i cant get ahold of anyone with actual experience in with a setup like this.

I am building a BOOSTED engine, but since I am personally building this engine, I am going to go WAY over the top on the cylinder head and bottom end in an effort to get as much air as i can moving through the engine.

So far the PLAN is to send the head off to SCCH and also ship them TT's 42x35mm kit and have it all done at one time.

I really want to know how streetable it'll be. Obviously programmable EFI is a must, thats already been figured in. A nice custom SRI is also figured in.

I dont need a bunch of people saying "you dont NEED to do that, or go that far" I want to hear from people that have DONE it and see what their feelings are regarding going this route with an OBD1 (or 2, really doesnt matter at this stage, does it now?) ABA cylinder head.

Ideally im THINKING that by overbuilding the engine, i wont HAVE to throw lots of boost at it to make the power i want. (Although we ALL know that "lots" is a relative term)


Thanks for the help!

(I am pretty sure that nobody in the FI section has this setup, so thats why im posting here, as it pertains more to engine building/NA than FI)

[Eganx]

with an OBD1 (or 2, really doesnt matter at this stage, does it now?) ABA cylinder head.

You will want to use a OBDI head, it does matter at any stage. The transition from the runner to the bowl is very different, OBDII being more restrictive. I built a ported ABA OBDI head with +1 valves, I didn't want to cut out the valve seats and cut the pockets bigger for larger seats for the +2......with +2 valves aren't the seats siamesed?

[Prof315]

I haven't done this but if you keep the cam mild (a must with boost) getting a nice docile idle shouldn't be too tough. As far as power levels go, there was a you-tube video of somebody with a big boost, big valve, max ported, SRI ABA (in a Mk1!) making over 540 whp.

[Minor_Threat]

I have it done 42mm intake, 35 exhaust




OBDII German head with titianium retainers, ported and polish work done myself

I'm running a stock intake manifold no SRI

[nextproject]

well thanks for the replies, i've already gotten more information/replies than the other 2 times i've tried to get information on this setup over the last year.

Well its good that it does matter if its OBD1, because thats what i've got. OBD1 german casting. Im planning on using a pretty mild TT 268/260 cam out of the G60 head im currently running.

Wow siamesing the seats, didnt realize that was going to happen, but im down with it, i wont be doing the work myself, likely will be sending the entire thing out to SCCH, along with the crank and IM shaft for some lightening/balancing.

So the much larger valves arent a headache to tune or anything? This will be my first foray into a somewhat "built" engine, its been slow going, but i've finally got the ENGINE i need, just need to start getting work done!

I'd like to hear comments on how they run, what the powerband is like. But i guess the powerband question pertains more to the boosted folks. Which are kinda hard to find, i'll look around on youtube though.

[911_fan]

I'm wondering why you are going with such a small cam if you're looking for such massive power.

[nextproject]

i'd still like to maintain driveability. usually the more aggressive the cam, the worse the idle and the dirtier the emissions. I dont want to perform a cam swap and retune every time i need to pass emissions. If theres a cam thats a little more aggressive but still has a nice idle (no more than 1000 rpm) and is able to pass emissions then let me know and i'll look into it. I guess thats a whole other thread though. That might be something i talk with jason at SCCH about.

[Minor_Threat]

I have a 276 cam in my setup, idle isn't bad, it kinda sounds badass actually, i have no driveablitly problems with it at all. I idle at about 1000

[911_fan]

There are a few cams available that will provide more usable duration and still give decent idle quality.

By reading your first post, you are looking for maximum power out of the thousands you are about to dump into your top end. While the 268/260 provides a nice bump in power, you still have a 260 exhaust duration. My suggestion would be to go with a TT266 or an AT270 cam. They both have a lot more lift and are symmetrical on both sides. Also, the 266 has -10* overlap at .050" valve lift and the 270 has 0* overlap. (The 260/260 has -1* @ 50thou) And both cams will have a good idle well below 1000rpms and both will pass any emission tests you can throw at it.

[nextproject]

thanks for the tip, i'll DEFINITELY consider this, these are both good cams for a turbo engine? i'll run it by jason and see if he can just tack it onto the bill.

[911_fan]

Uh...you can take my word on that. THose two cams will work great and cost a LOT less new. You can even pick up a used cam for around $100.

[Mtl-Marc]

... So far the PLAN is to send the head off to SCCH and also ship them TT's 42x35mm kit and have it all done at one time.

Update?

[nextproject]

i've got my estimate on the work, got my aba head stripped down and ready to send, but now i realize that it may be better to have the SRI made first so i can ship that along with the head so that it can be port matched, assuming that the overall shape of the intake ports is going to be vastly different.

i saw a setup for sale in the classifieds recently that makes me thing doing it this way is the way to go, so for now im concentrating on having one of the tex members here fab up an intake for me, i've been in contact with nubvr, keep in mind this build is still in the planning stages, but i think i've gotten the mechanicals sorted out so far, i've gotta head to the junkyard this weekend and look around at throttle bodies and cables for the sri and ship some parts out so that the SRI can be made, then once that is returned to me i'll be able to send it to SCCH.

My plans for the head also include shipment to Swain Coatings for several of their coatings for the combustion chambers and valves and ports.

[911_fan]

If you are looking for an SRI, I think you should get this one...

http://forums.vwvortex.com/showthrea...&highlight=SRI

It's my old manifold. That was built to MY specs and I measured out EVERYTHING...taper, runner length, plenum volume, ect. Its designed to hit 2nd harmonic @ 6800-7000rpms and 3rd harmonic around 4000rpms.

You will not find a better designed OR fabricated manifold anywhere. I can guarantee you that.

[nextproject]

Interesting you mention SVi, Greg is the guy that made my trunk-mounted AW reservoir, AW intercooler, and intercooler piping, i'd really like to get the manifold, but as of right now im liking the price of the one im going to have built by nubVR. His work looks pretty good too.

Im just not ready to spend a grand on a manifold and fuel rail. I am very interested in what kind of TB and cable you are using in that setup though, as that information can help me alot right now.

Its a gorgeous SRI, and im very familiar with greg and his work (he lives 30 minutes from me) and i agree his work is top notch, but the price is a bit steep for me.

[nextproject]

well i made what i considered to be a decent offer on the intake manifold. more importantly i would like to know what throttle body and cable setup was used for that. any chance you could share that information?

[911_fan]

I used a VR6 throttle cable. For the throttle, I used a stock one. But I did some reshaping and port work to it.

[eurotrashrabbit]

[nextproject]

nice setup! currently gathering pieces and sending money for the ABA SRI to get built. as of right now i just want the turbo g60 engine to run while i build up the aba. i think i am going to have proline race engines in atlanta assemble the bottom end, IF i dont do it myself. I've already got everything for the whole engine spec'd out. Just got to find the money to make the necessary purchases and then start spending it!

That car looks like alot of fun.

[Rosten-Performance]

42x35 valves will loose power,the valves are WAY too big.
Even with a 85mm bore they are too big.
Bigger are not always better,believe me

[Rosten-Performance]

Below is the facts

Tested on a flow bench with a 85mm cylinder underneath
The engine used a 85mm bore too ofcourse
39mm VS 41.50mm intake valves
Sorry,i don't know how to post up the flow chart so i just copied the numbers
with a smaller bore the difference would be even bigger

Lift 39.0mm 41.5mm
2 47.4 44.5
4 82.9 79.6
6 110.8 110.2
8 134.5 132.0
10 146.7 148.5
12 150.7 147.6
14 152.9 149.8
16 154.6 152.0


This engine used a 39mm intake and 31mm exhaust
1600cc counterflow 85mm bore 70.50mm stroke
Normally aspirated 13.7:1cr
Made 193 crank hp

Some will maybe think that since the ABA has a longer stroke and more CC it will be a complete different engine to compare valve size with,but i don't believe so (unless someone prove me wrong)

Problem with big intake valves are that they comes too close to the cylinder wall and that is a disaster for the intake flow.
A too big exhaust valve is not that bad,since it can be corrected with cam profiles and correct tuned headers.

[nextproject]

given that the head being built will be used for pretty much "all-out" turbo power, and not naturally aspirated, what are your thoughts regarding that? I know this is an all motor forum, but havent seen FI guys upgrading the valve sizes, just upping the boost, i would like to make the engine more efficient, instead of just throwing more boost at it (I already plan to use water/meth injection, im not SCARED of throwing boost at it, just would rather try the "efficiency is key" approach).

[Rosten-Performance]

Well,intake valve size will have pretty much the same effect (if not more) on a FI motor.
The "rule of thumb" is that the clearance from the intake valve to the cyl wall and combustion chamber should be MINIMUM 12% of the valve diameter.
So a 42mm valve requires minimum 5mm clearance.
That is impossible to achieve with a 82.50mm bore.

So bigger bore,relatively small intake valve and a better cam would work best in your case.

[nextproject]

basically then the intake valve should (ideally) remain stock sized at 39.5mm. Any sort of "rules of thumb" regarding the exhaust valves? I guess its back to the drawing board then regarding how to improve flow without hurting it in the same way.

[ny_fam]

Your example was on a counterflow head. Impressive numbers too I think nextproject is talking about a crossflow.
I agree that larger is not always better on either head.
Wwe were considering using larger intake valves to help aid low lift flow, low lift is really anything below .500". But we we not willing to give up any velocity.
We did a crossflow head this spring for a turbo 2.0 crossflow car using stock supertech valve sizes, and the customer
was very happy and surprised the engine builder how much power they were making. Our flow results are on our website. I would recommend larger exhaust valves now though. Good exhaust flow ratios are hard to get to on these 8v heads.

Rosten-Performance I'd like to know more about the induction system used on the 1600. Sounds like a formula super vee engine running ITB.

[nextproject]

thanks for chiming in, btw im very happy with the "stage 3" intake i bought from you last year. its currently on my G60T running 15psi, i'll dyno it when its all set, although i cant imagine it putting out more than 200whp, thats why im building the ABA.

You are correct, the engine in the planning stages will be an OBD1 ABA engine with short ram intake manifold and turbo. So yes, the crossflow head.

So am i right in thinking that some porting/polishing along with possibly 35mm exhaust valves and small stem/high flow 39.5mm intake valves might do the trick? The plan is to ship the head to SCCH and have Jarod work his some magic, although originally i was going to also incorporate the TT 42x35 big valve kit.

But thats why i posted this, thats what the experts are for, since i dont exactly have the time and money to purchase several different heads and valve sets for each one and test each one on a flow bench at various lifts.

[ny_fam]

Jarod @ SCCH has the experience with those valve sizes. He also can flow test for velocity. I'd ask him before deciding.

[Mtl-Marc]

Below is the facts

Tested on a flow bench with a 85mm cylinder underneath
The engine used a 85mm bore too ofcourse
39mm VS 41.50mm intake valves
Sorry,i don't know how to post up the flow chart so i just copied the numbers
with a smaller bore the difference would be even bigger

Lift 39.0mm 41.5mm
2 47.4 44.5
4 82.9 79.6
6 110.8 110.2
8 134.5 132.0
10 146.7 148.5
12 150.7 147.6
14 152.9 149.8
16 154.6 152.0


This engine used a 39mm intake and 31mm exhaust
1600cc counterflow 85mm bore 70.50mm stroke
Normally aspirated 13.7:1cr
Made 193 crank hp

Some will maybe think that since the ABA has a longer stroke and more CC it will be a complete different engine to compare valve size with,but i don't believe so (unless someone prove me wrong)

Problem with big intake valves are that they comes too close to the cylinder wall and that is a disaster for the intake flow.
A too big exhaust valve is not that bad,since it can be corrected with cam profiles and correct tuned headers.

Thank you.

[Rosten-Performance]

basically then the intake valve should (ideally) remain stock sized at 39.5mm. Any sort of "rules of thumb" regarding the exhaust valves? I guess its back to the drawing board then regarding how to improve flow without hurting it in the same way.

There is always a "rule of thumb"
3-5% of the valve diameter for the exhaust valve
But the cylinder diameter will also play a big part.
Head porting and valve sizes is a VERY complicated subject for sure.

[Rosten-Performance]

Your example was on a counterflow head. Impressive numbers too I think nextproject is talking about a crossflow.
I agree that larger is not always better on either head.
Wwe were considering using larger intake valves to help aid low lift flow, low lift is really anything below .500". But we we not willing to give up any velocity.
We did a crossflow head this spring for a turbo 2.0 crossflow car using stock supertech valve sizes, and the customer
was very happy and surprised the engine builder how much power they were making. Our flow results are on our website. I would recommend larger exhaust valves now though. Good exhaust flow ratios are hard to get to on these 8v heads.

Rosten-Performance I'd like to know more about the induction system used on the 1600. Sounds like a formula super vee engine running ITB.

The engine is used for a hill climb racer.
Not ITB's just dual webers,but a very custom intake manifold.
Intake manifold is based off a plate with holes for both intake and exhaust ports,the header holds the intake manifold in place.
So there is no bolts on the intake manifold itself,carbs are placed very close to each other and the linkage is attached on the outer ends of the carbs.

[PBWB]

To the OP.....I already have something similar done. OBD1 head, solid lifter conversion, 288* one off cam, etc. The head flow chart is here.

-My-ABA-flow-numbers.....SCCH-is-the-shiz-(officially)

I too share your mentality about going with a more efficient design so I don't have to boost the crap out of the motor to achieve my goals.....so we are pretty much on the same page you and I.

I've been fortunate enough to secure a sponsorship with Jarod, and we've worked out a lot of things that were brought up in this thread. I will admit though that I'm a bit worried about the area in between the valve seats cracking (but whose not?). Jarod definitely knows his stuff about doing these heads up, but a couple things are certain: Ask every question you can think of, and give every detail to your setup possible. This will help him determine your best course of action. I don't have the car running yet, but I'm aiming for over 500whp, which a few well known big players in this game say is easy money with what I have goin on.

Hope that helps.

[nextproject]

i've been considering a shim-under-bucket designed solid lifter conversion as well. i've adjusted enough valves in my day to not shy away from having to do it every so often on my project car. besides its only 8 of them! i'll look into it, my quote with jarod and swain technologies is already right at 2k. which is perfectly fine with me considering that other than being converted to solid lifters, its pretty much a maxed out head. My custom short ram intake is coming back from nubVR as we speak, so now its just a matter of saving a little more before i ship my head off to jarod, i really do need to speak with him some more, i've already spoken with him a bit already over the phone.

thanks for the flow numbers, those are some serious numbers for a small 8v head! is cracking between the valves a major concern when running larger than stock valves?

[PBWB]

thanks for the flow numbers, those are some serious numbers for a small 8v head! is cracking between the valves a major concern when running larger than stock valves?

Thanks. And to be honest, I wouldn't call it a "major" concern per say, but it is never the less......but more so in extreme conditions (high CR, stress, and boost). If you're still planning on going n/a and this car is a weekend car for you, I'd say you're fine. Just take care if it like anything else. Now if you're planning on putting 20k miles on it a year, I'd shy away from going that large with the valve sizes, and lean more toward maybe a +1mm intake and +1.5mm exhaust. But pay little mind to me and wrap things up with Jarod, he ultimately knows best. Also, he's quite busy right now so you might want to get ready to ship that head very soon so you can get in line! He's got a lot going on right now.....

My mentality going into this project has changed a lot but settled with the fact that I'm probably going to take it to 40psi regardless of how well the car does, JUST to see how well the car does. Only the crazies in Brazil are going that hard on these motors, so I'd like to see if I can't throw my name in the hat of quickest 8v cars around. Only difference is mine is a street car (just like the mk1 rabbit from Black Sheep Performance....he's the guy with the 540whp in Nevada that was referenced earlier in this thread).

[nextproject]

however much boost, water/meth, tuning it takes to get me to ~450-500whp on a "high boost setting", thats what im shooting for. I don't plan on dailying it at ALL. It's a toy, something to showcase my taste in cars and modifying them.

That being said i'd love to be able to travel to places such as shows and some sort of motorsports and what not, and drive the car to those places. So some miles would get put on it. Low boost would be alot less, whatever is daily-able considering that 500whp out of a FWD car is beyond overkill, i'd settle for 300ish.

The valves and combustion chamber faces and runners will be coated by swain technologies, i wonder if cryo-treating the head would lend any resistance to fatigue. Couldnt hurt i guess. Its only money. (I say that now)

[PBWB]

Well the gurus of drag pretty much tell me that boosting the crap out of the stock head is all you need to make 450whp....so I'm sure you wouldn't need to go as crazy as I'm going to get to 500. Just make sure you have the manifolds to compliment the system, cause a tiny ATP turbo mani and mk4 intake mani would never come close.