Rightin the 8v forum there is a 'is it worth going crossflow?' thread, on there it has been discused that a standard crossflow will flow as much as a ported big valve head. This got me thinking about standard 16v heads and what they have acheived. How far can we take a 16v head, what LBFT can be acheived with it if the rest of the hardware is optimised to the setup? What would be required to react the optimum setup? what cams? what CR? what inlet? And finally are some of our ported heads reducing our power and torque figures? as there are many engines out there which have had money spent on porting but have gained little if not have been down on expected power? Can you acheive the majic 200BHP with one? I going to dig out some of the known engines and there specs for references.
Gurd's MK1 standard ABF engine on MS has made 181.5BHP and 166LBFT - this is just an optimised map. PAB's 16V Jetta has standard head 288 newman cams and Dellorto's 45's (38mmchokes) wossner 12.1 comp pistons 201bhp on Rollings when first built. But latter made 188BHP at the Wizards RR Day. Infinity's MK1 standard ABF engine with 48mm Jenvey ITB's and 8 injectors. 176BHP 146LBFT - not fully mapped yet?
For stuff like that it would be best to put all the data in sdimulation software, like a dyno 2003 or similar and workout the effect of everything working together. The head made be able to flow that amount of air, but the throttle air duct may not like it, or the throttle is too small or the intake manifold is not tuned right, the exhaust is too big, the 4-2-1 should be a 4-1.... the cal is not at MBT or LBT for the given conditions...and so on and so on. The flow is just one thing that can influence VE and possibly torque.
PAB's 16V Jetta has standard head 288 newman cams and Dellorto's 45's (38mmchokes) wossner 12.1 comp pistons 201bhp on Rollings when first built.
I like where this thread is going. It would be easy to confuse it with another 'how do I get (>)200 brake' thread, but what it appears doing is challenging a bolt on, box ticking mentality. Can you fence off the extreme spec stuff / define specs a little, so we can 'keep this real?'
You will need valves in that mind, compression may be a little low if you leave them out. PAB's made around the mark as Brooky has mentioned already. Therefore the above stated flow to bhp potential is somewhat off.
Pab's made arround 188bhp at the Wizards RR Day so it would be good to see comparable engines on the same rollers on the same day with standard heads. i.e. infinity, Pab, Gurds.
I was going to mention this earlier but sh** out really lol. As said it'll depend on the rollers. As we've seen of late, 200bhp valvers aren't anywhere near 200 on certain rollers.
Hi trying to find out what is really required for high HP and possible 200BHP. IS a ported head necessary? or are we all just wasting lots of money getting this done because it has become the norm? are there other ways to optimise valvers that will produce prehaps better results than a ported head? after im sure VW did their homework and decided the ports would offer enough flow and velocity - other marks seem to have small ports, bigger velicty heads that produce really good figures...
Ports aren't ported from factory for 2 reasons. 1: The expense/time aspect 2: engine's gotta give both economy and performance at the same time. VW have put millions into development but for a road car, not a track car.
But what is the limit of the standard ports/head? Gurd's is pushing 30BHP more than what VW intended, he has not changed the CR or the cams etc etc, what would happen if... What do we know about standard heads? what is this the limit people have taken standard heads too? is it 188BHP - PAB? what is the specific engine spec that he is running to achive this? Why does it work? Why is a ported head always suggested when people want more from their valver when we are only talking 2.0L 150-180BHP, would the money be better spent changing, modifying other parts?
Raise the compression with pistons and install cams to match, no need to port the head. You can improve the efficiency in several ways. Hot rod and F3 engines are often "restrictor engines" and work by running an artificially high comp ratio, knowing that the cylinder will never truly fill due the the flow restrictions in the intake system through a fixed orifice in the air intake or a std carb choke size.
I think people take the line of least resistance on this stuff. Everyone starts with an air filter. 10 min job or an hour's faffing breaking clips, it's the one that gets folk started. The exhaust, seeing as the old one's rusty, coming to the end of its life etc. Then it's the head. Cams first, and/or may as well port + flow it at the same time. Add a vernier maybe? That's it for most folks, traditionally anyway - cue dyno shoot out time to see the fuits of one's labours. Folk absolutely refuse to touch the block. Too involved, infers taking the engine out, can't be bothered, complexity, potential for cock ups, general lack of faith + understanding etc. Nowadays, it has all changed, the cars, the parts, all had for cheap. Even saying to someone: "change the ECU" is not an easy sell, even if some of us might believe it's easy. MS made it financially easier and great for anyone with the knowledge to put one together, and what got Gurds moving was he had an ABF on K-Jet which he wanted to run on an ABF ECU at one stage. Having it sat on the J-Ket was I suspect bugging him as a backward step - and the rest is history I suppose + a big insight!
Because the modelled port on some matlab based device, can flow enough air for OE targets and the casting process is good enough, fast and cheap to not justfy point 1. Point 2 already modelled in design. We enthusiasts are trying to make a road engine and setup into a track application with a limited budget. Hence the need for services from people like yourself, Mr H and Man in the shed. But this question came up when Gurds and Gurds tested they std engines recently at Garage Streamline. Infinity's application was 175BHP but was down in torque due to issues described in that thread. My opinion about that car is that it would had the peak power as Gurds K, but a different and lower torque profile. I cannot speak for PABs car and the measurements number, but the torque profile can still show some clues as to if this is achieveable or not on STD Head components. Ben S and his manifold optimisation study is also showing promise on clawing back a few torques at mid to part higher RPM as well. A delveopment that may imported on vw_singhs car. The little table showing how much torque is required to achieve this 100bhp/ litre number at various engine speeds was calcualted and it does look very hard to claw back 11-14lbft on std hardware in the higher engine speeds of 6500-7000 rpm. What we do not want to do however is to compromise torque to under 150lbft from key lower engine speeds and certainly will like to keep this in the 160lbft+ region. We are working on which path will be used and if it is required to spend some to release more torques and range. By increasing the torque and rpm range where it stays high will mean closer to 200bhp peak number will be achieved. This does take a lot of dedication and harware and mapping changes are occuring at the saem time. We are also using modelling packages to play with settings offline to help with hardware selection if we have to purchase something a bit expensive. But as I told Tom, the head in theory can flow ~190bhp of air. But this is a very crude calculation that does not say +/- XX%. This XX%, X% or if this is -ve or +ve will be dertermined by hard controlled testing. Bring on next year I say...
This is a very well made point, and I for one am apprehensive to start fiddling with blocks, I have had to many expensive rebuilt engines die due to poor components/or skills buy the builder. So I shy away from touching them ATM. But can we raise the comp in other ways? yes, but how much and in what way? as most of use know higher comp (and an appriopriate cam) will lead to bigger figures, but will this still work on the standard head? Use the 500 porting costs to increase the CR? uprate the cams? add a verneer? add individual cam verneers? light weight valve gear for more revs? 8 injectors? ITB's? custom plenums? What combination of components will get people the furthest? and how/why?
Something that came up the other day was: Has anyone actually burette checked the complete clearance volume (not just head combustion chamber volume) in the various 16v configurations to establish the true compression ratio? Head chamber volumes have been checked several times and are 45cc as standard. I have seen many calculations based on the maths using the oem factory compression ratio. I can say that on the engines I have actually cc checked that the VW numbers are not near what they state. My checks were on 8v engines that are easier to check when the engine is built as the plug hole is so accessible. Mk2 1.6 EZ code engines are listed as having a 9 : 1 ratio when it actually measures out at 8.3 : 1 Mk4 1.6 AKL code engines are listed as having a 10.2 : 1 ratio when it actually measures out at 9.5 : 1 One thing to be careful when buying pistons is check the compression ratio carefully. A lot of the American companies are selling forged pistons with a 10 : 1 compression ratio for NA use. That is crazy if you are spending that sort of cash for no appreciable increase in compression. 12 : 1 is more like it.
