Hi all , getting back to the original thread have you considered Piper 276/274 ? a tick-over to die for and loads of top end grunt . On the subject of Rolling Roads , having spent many an hour at TSR and seeing many a car in various states of tune. I honestly believe their rollers to be reasonably accurate !
32% transmission losses! I thought it was closer to 20% for a Golf at a push - I could be completely of the Mark tho'.
Hi i was having a search and I found a DD plot with the CFJ reg in it here, looks to be running rich in the mid range hence the low torques - i wonder what happend to the BHP's. Mine is running a little rich top end hence my low power, I dont believe it is due to the ITB's or the size of the cams I have as stated earlier - just needs a good tune
is this still the case with a quaife diff fitted? ( i have no idea if this would effect things) i can only highlight what my dad has said about tsr rollers, i have spent hours and hours down there while they have got the car to run the way it does and i have also seen standard cars roll what they should do. so i happen to believe that there rollers are very accurate. its just a shame that we couldn't attend the 16v rolling road day due to a family bereavement but we will sure to attend the next one when it is organized. we have had to change many parts including having the fuel tank completely cleaned out as bits from the tank were passing through the filter and getting into the fuel system and causing problems. back onto the initial question on the thread. Chris as my dad has said the pipers give a great tick over(although the neighbours arent so keen when i leave for work at 5am lol) and plenty of grunt from 5k onwards. there isnt much low down it picks up around mid range then goes ballistic higher up the rev range.its not really a problem though you just have to ensure your in the right gear its a shame you dont live closer to us as i could take you for a spin so you could see for yourself.
I do admit though that Maha machines are very respected if used correctly. On dynos such as this one, coast down losses are just usually summed up with the wheel measurement and leads to numbers that can be very large. This is explained in this article by Puma Race Engines This article suggests a crude method to estimate 'bhp' on a FWD when wheel power is known. bhp = WHP +10 * 0.9. I must admit this should only apply to the peak value as in other areas, such as low speeds CST are longer and the losses are less. Also on a VW FWD driveline losses tend to be ~14-18% at the power peak. 32% loss as suggested will inject enough heat to put your gearbox oil on fire! That is just measurement and reporting though. It does not change how the car feels. While this plot confirms that the TSR package is working as they designed it, it does not mean that the car will react exactly like this if accelerated and logged on the road. Relativity goes out the window if a reader was to see this, try to reproduce this engine spec in their private garage, then test on another make of dyno on a dry day with low pressure only to be disappointed. This one of the reasons I wrote the typical 16v dyno plots essay to highlight the feel of a vehicle vs actual measurement and bring in the G Force aspect to make it all relative to anyone.
Further from my above post I had a call earlier from Mart telling me that my engine was ready after all his hard work putting it together It's exact spec part to part isn't something that I could put down in text accurately so I won't, if Mart decides to add exactly what has been done then that'll clear that up. Basics of my engine is that it's still a 1.8-16, now has a 10.7:1 compression ratio, ported and flowed head, 50mm inlet manifold matched to the head and newman 272 cams. Will also have a lightened flywheel. Once it's back in the car it'll be setup as best as can be by a local rolling road tuner, one which Mart has used on his 2.1 ABF. It'll be interesting to see what can be achieved by old school tuning for one, and second I'm thinking about going MS over the winter with ITBs so it'll be nice to see what the difference if anyone cares
This was years ago, I've owned the engine for about 12 years, this was approximately 02-04. The conditions? No idea, can't remember what happened last year, nevermind 8 years ago.
Nothing wrong with old skool tuning. The chap who set up Marts car did a good job from the plots that he sent. Just that carbs dont like big swings on ambients! The PwrEng thing sounds like that test was on their old dyno which would explain the "156bhp number. However I am doubtful that testing this same engine there now ( as their have a DD450DS unit) would result in the same numbers, more like 145ish@6600rpm at best. BHPs in the 150s are for STD ABFs.
Would be impossible to test that same engine now, for one it's been pulled apart and rebuilt, and it's done about 40,000 miles, a head gasket, and was running like a bag of ****e on its last track day, vacum hoses had started to collapse, ignition module was breaking down and it was revving like an 8v. It was a very good engine though and revved exceptionally well, better than the other 16v's I've had over the years yet it's never seen a set of cams or any other fancy bits thrown at it. On a tangent, in my mk1, on road avon tyres it was being not left behind by Paul Haslems Cabrio on R888's at Llandow. Must have been giving away 30bhp to his ABF at the time and the additional grip from the R888s.
The "0.9" calculation is'nt a mile off based on figures I've seen from the rolling road from the same engines off the engine dyno... "around" 15% so close to your findings too. Thats why I generally ask for wheel figures when flywheel figures have been calculated off a rolling road...if there's a massive difference over around 15% then something is amiss. There's a big chunk of low-midrange torque missing from the car fitted with the 274 cams... plus going by it peaking very late I'd imagine the cam timing &/or phasing is out. You dyno plots essay is interesting... would be good to see some wheel figures too... not so I can check up on you! ... just to show folk real world losses. We had countless KR's on the rollers many years ago, 98% of them made 112 at the wheels.. a bad one was 107-109, a few good ones made 114, and all had the "dip" in the curve. We had a std ABF MK3 in that made 135 at the wheels.. I made the chap do it again while I watched and it was certainly there... never saw one do that before of after. Std VR6's would make 142-145 at the wheels...std MK1-MK2 1800 8v's 87-90...Mk3 2ltr 8 v's similar but better midrange.
The Puma link really helps in checking a peak wheel number back to a sensible official reference but only refers to a peak and still does not address the parabloic nature of drivetrain and line losses as the vehicle deaccelerates from a maximum speeed in gear. I more interested in the absoulte quality of the entire trace which will lead to better understanding of where engine breathing/TQ maximise (i.e. @ rpm) in these engines thus translating into the a correct power estimation be it wheel, hub or flywheel and how this will correlate when subjected real life creating a common reference for all.
tyre sizes & pressure, gearing etc should be logged too surely when trying to assess transmission losses?
Very true Eddie.. though if your carefull a good ballpark guide can be found. On estimating a peak torque figure based on wheel figures on a given engine I calculated around 148-149 ib/ft... on the engine dyno the same spec engine made 147... so fairly close. I've never found a big difference on tyre pressures. I read an article many years ago that a big pressure increase (around 10psi) can bump up figures due to side wall flex/absorbsion between the two rollers... we tried it and found no change within a normall operating window. Maybe if you ran a car with 15psi then upped it to 30-35 you'd see a difference, but in the normall 30psi zone, adding or dropping a few gave no change. Knobbly rally type type did however make a massive difference.
Same car, here's the Stealth one: 170bhp / sub-150lb/ft or 202bhp / 160lb/ft 'Dyno Lottery' starkly illustrated!
