250 isn't quite top tear, but getting close with commercially available parts and some kind of shelf life. Much over that and the cost will go nuts...15k+...and regular re builds/inspections would be the norm. Rpm wise, power is long gone by 9k, think 8 to 8500 as absolutely more than enough. I'd be aiming more towards 8k tops and 230hp / 175ibft, which wouldn't be slow.
You are doing what you have to to sell products. No problem with that. On a weekly basis, I am consulted weekly to fix cluster fuck ups created by tuners who target the highest dyno readings on their client's cars. One drive with most of those dyno tuned cars and I do not have to go far before I have enough. Many driveability issues with vehicles like that. And I have to condense time, getting such vehicles working to the expectations and psychology of the customer with all sorts of tuning methods in 3 or 5 hours so. You know fully well I am former and current OE professional who understands what it takes to make a powertrain driveable to the public. So I use my part time work tuning modern and old school road and track vehicles to enlighten and guide those who ask honest questions regarding making their cars faster. I feel curves, shuffles, dips, can smell enrichment or enleanment, hear det while on the move or during maneuverers and can predict what full load acceleration can be like on certain chassis at different pedal angles and have certain drive feels memorised depending on what the powertrain is. Add instrumentation and I become pretty much am part of what is to be done. Hence, horsepower peaks are tools used by OEs to market their products, well at least in the petrol high performance era, but is not the key ingredient to driveability for an engines operating range. I am happy to champion educating enthusiasts on that fact, rather shoot for XXXX bhp, stg 1 or stg 4 and such nonsense. Most actually do not understand how it all works I am afraid.
It says BHP on the graph Airbox is the standard 16v airbox with most the bottom cut away. This is the Dyno graph, says BHP: https://i.ibb.co/M7nVQqX/MK2-Golf-GTi-16v-dyno.jpg Thanks, I'm not sure what else to refer to for an i I'm not particularly fixated on the end number especially, but a where about target of what is achievable. The RPM to power point is surely going to depend on the head work for head flow and the cam spec? Or are you saying that 16v heads just can't flow air for good power at 9k rpm no mater how much one modifies them? 8k and 230hp/175lbft would be nice.
You are fixated on power. This type of discussion has to have more detail than what folks talk about on facebook. It is the torque that allows power to be advertised at full load. So ignore the magnitude of "230bhp". Let's add some detail around that to estimate vehicle acceleration. You need some experience to construct that, but that is why you are asking the question on this forum. You will not achieve 175 lbft at 8000 rpm. Not without making the engine peaky and useless at lower engine speeds or running a bit of forced induction. I can back calculate what your proposed curve could be, based on 16v engine characteristics, pending a net sum of parts and of course in absence of any specific dyno. The numbers I choose and engine speeds are purely my observations of vehicle gs and dyno experience and will vary from place to place and dyno to dyno. At say 7500 rpm you achieve 230 bhp, the torque is 161 lbft or 219 Nm. Typically a 16v has maximum torque 1000 rpm before the peak power measurement and usually under 10% higher than at the maximum advertised power reading. So between 5500 and 6500 a typical 16v plateu and range, you can achieve about 175 lbft there. At 8000 rpm, airflow from the cams you chose, the throttle length and the exhaust system with be dropping off at rate greater than the engine acceleration. Hence suggesting about 130 lbft at that point assuming typical aircharge via the components chosen and tuning. Your KR dyno graph for torque at ~ 170 Nm (125 lbft) from 5000 to 6000 rpm is pretty much the type of trace profile you would get if you were to accelerate the car on a flat road and recorded gs. This assumes the ramp rate of the dyno is 100% consistent. So assume for a moment my theoretical torque for a modified 2.0 16v engine were to correlate to your graph . It is likely it would not but let us imagine. 8000 rpm engine with 230 bhp @ 7500 rpm and 175 lbft (238 Nm) from 5500 to 6500 rpm and 150 lbft or 204 Nm from 4000 rpm, and compare this result in torque from your 1.8 16v plot and with the same gearbox, you will be able to crudly simulate how much more acceleration you would have. Go out in vehicles with a similar characteristic to your desire and from there you will be educated to project manage your requirements into a real proof of concept. Hope that break down helps you.
Remember, VW engines of the 1.8 and 2.0 ltr variety are long stroke engines, this is a very important factor in developing VW engines of this type. The 2.0ltr, even at 8500rpm, has a piston speed in the upper region of a typical F1 engine,....so you are on borrowed time if you run the engine at that level for any period of time, it will destroy itself simply due to the laws of physics. The 1.8 ltr engine has a little more margin as the stroke is shorter, but there is no need to be reving over 8.5k with proper development....which is easier said than done at clubman level mind! The 16v STW/BTCC Audi engines of the mid 90's were a similar engine type and made around 305bhp at under 8500rpm. The RPM limits were driven by regs, but even they reduced the stroke to 90mm then to around 88mm to operate at 8500rpm max reliably........but they then needed special blocks due to the bore centres, to get the bore up to around 85mm bore to get the CC back up to 2.0ltr. There are other reasons for a larger bore, but the big reason was piston speeds at the VW/Audi stroke length. The trick was to develop the cylinder filling to an optimal position at the given RPM range, and that was driven by mechanics. The fuel and ignition mapping is dictated by the mechanical spec used (good or bad) and it can take a lot of time mapping etc. to get the best out of a given mechanical package, especially if it is a sub optimal design to start with. The trick is to spend time working out the best mechanical set up for your intended use, then spend equal time getting the ignition and fuel optimised for that spec once built. A lot of planning needed before you spend and a penny or cent, then a lot of time setting it up to run right and give its best. One without the other will leave a lot of power on the bench. So, with the level of resource and money that VW/Audi have you can achieve around 305bhp.....so that should be considered the upper limit for any realistic power/RPM target.....then temper that by the fact we are not VW/Audi and have extremely limited budgets and resources comparatively. So 20% down on a full works engine at 250bhp is a pretty good result at clubman level and perfectly achievable, but remember that will absorb 10k to 20k GBP if starting from scratch, depending various factors like new/second hand parts and how much engineering/machining you can do yourself. Unless you want to start spending big money on bespoke short stroke cranks with the associated long rods and bespoke pistons forget about running at anywhere near 8.5k rpm. The engines will take 9k+ when buzzed on down shifts or hanging on to a gear; my 8V race engine tacho tell-tale has recorded 9.6k, but that is simply as a result of over reving for a very short period with decent components and only due to conditions or gearing......you simply cannot run the pistons at the piston speed a 92.8mm stroke crank generates for any length of time. I'm talking about competition engines for the most here, but the principals are the same for all engines, the laws of physics are not very flexible.
To be honest I haven't seen any definitive proof of bespoke 'std' blocks, but being Audi/VW they had the resources and scale to put special castings through the normal production as and when they wish....they were certainly heavily modified for use in STW/BTCC. I've heard some of the later blocks were fitted with liners, but personally have never seen any proof of that. The bore centers had to remain the same as std due to regs, so the bore dia was very limited with the long stoke VW/Audi 16v's. I do have a later Audi STW 16v head here, and for sure whilst it has all the normal casting marks etc, and looks much like a std production item, its clearly not, its a special casting :-). Interestingly, the ports and valves are not huge, infact the port size is not visually that much different to the std head in scale, but clearly there is a lot of detailed development to get from the 139bhp of a 9a to 305bhp of the later step 7 and later STW race heads. This thread is not the place to go it to the STW motors in detail, but there is a dedicated thread in this forum that goes into a lot of that detail.....its probably the most definitive exploration available of that engine.
The stw blocks were picked from standard abf blocks (abf blocks are not all exactly the same in room around the bore some can be bored to 85mm) i once posted pics and dimensions from a stw engine i dismantled and rebuild. but i don't know about the last spec of stw/btcc engines which were over 295 hp. i once bought a new (empty but prepared) stw block from mtk and they confirmed it started as a standard not special casting but picked abf block. greeting and best wishes for 2024 from the Netherlands!
I went Supercharger to get a bit more pep, and more torque in a usable rev range (for me anyway). Have to much mechanical sympathy to Rev to 9rpm!. Be interesting to drive one of these 300bhp monsters but personally I wouldn't like to own one.
I know not the same thing but our MK2 with the R32 and 277hp is awesome. It’s easy to drive round town and goes like a scalded rat. I’d be happy to use it as a daily, indeed my son does but not as much as he would like due to ULEZ. TBH I don’t think I would ever get rid of it, just too nice.
Sounds good, the R32 is a good engine. I have a Mitsubishi GTO 3.0 Twin Turbo as well (around 500bhp) but that's needs to be up in the revs to spool the turbos (TD04-16g's). To be honest 99% of my driving I would choose our Diesel MK2 Kuga, instant torque and fast enough. Must be getting old!.
I get your point, my question would be what your ideal n/a 16v would look like? Also keep in mind that not everybody chases maximum driveability or acceleration. For some people, it is just fun. I drove an ABF from my engine builder, which made 240bhp and 190lbft and it was a hoot, I did not care if the car was slower or faster than any other car, the power curve was super fun to drive, throttle was crisp and very responsive.
Maximum driveablity and acceleration, require correct calibration of engine torque and tuning the attributes responsible. It will cover the entire load envelope of the engine. If the tuner has a good grasp of the entire the powertrain, including the gearbox ratios and wheel sizes and vehicle weight, he can target the transients up from idle to full load to create the fun to drive factor. Peak power or peak torque does not define that task. And the numbers quoted are often meanless by themselves without correlation to g forces felt by the driver. I am not sure there is an ideal NA EA827 16v without context. It depends on what the vehicle is used for and what chassis/weight class it is fitted in.
So your ideal 16V would be done in a way to ensure good low-end torque and not chasing higher peak power, if I understand correctly. So basically maximum acceleration over low, middle to high rpm range. I respect that, however not everybody is chasing that goal. From an emotional point of view, for some people it can be more fun to have a high peak HP engine with less mid-range torque, because this engine would be more "rewarding" when reving the engine out, because the power output difference from mid-range to high-range rpm is more different. What I am trying to say, not everybody has the ideal 16V engine. Even for me, I don`t care if the engine is built and calibrated to ensure maximum acceleration with the given hardware. I don`t build my car for races or anything but me and my enjoyment. I myself am a calibration engineer so you can be very sure the engine will be calibrated pedantically, but I already know that my hardware (Cams, intake lengths etc) are set for higher RPM peak power instead of mid-range torque. There is always a physical aspect to it, you can`t tune a race engine with 315° cams the same way as a rather stock one. Therefore I think that on the level of the general discussion here you can tell a lot from the information about peak hp. A 280hp 16V will never have the same torque in lower to mid-range rpm than a well made 16V with some mild cams - anybody who achieves that is either lying or cheating. So if anybody wants to have 250hp, the general goal and direction is quite clear to me. It is most likely not faster to drive on the road than a 190-210hp 16V, but who cares? Is it more fun to drive? Depends on the taste of the driver.
"So your ideal 16V would be done in a way to ensure good low-end torque and not chasing higher peak power, if I understand correctly. So basically maximum acceleration over low, middle to high rpm range." You do not chase power as a calibrator. You optimise the range of torque/cylinder fill for the engine hardware. Power is just a by product. Your 250/280/190 "bhp" is single point byproduct. Tuning for the best feel for a given hardware, like a EA827 16v, is a series of experienced calibrations for transient load changes. Most folks do not understand that, and is evidenced by the vehicles I see and data log during a consultancy, that have been tuned at full load on a dyno.
