Turbocharger Posted December 10, 2005 Share Posted December 10, 2005 No prob - I'm sure I'll find some way to guesstimate the converter slip. So long as you don't lift off until full revs (4500rpm??) then it's not to hard to evaluate, although it will give some considerable margin for error. The before/after %age improvements should be comparable though. PM me if you want more specific instructions, cheers. Quote Link to comment Share on other sites More sharing options...
Steve H Posted December 10, 2005 Share Posted December 10, 2005 Is the 2.8 the Iveco lump rebaged The Iveco 2.8 as used in the Santana PS10 & a million Fiat & Iveco vans & light trucks is an OHC engine & nothing whatever to do with the 2.8 TGV engine. Quote Link to comment Share on other sites More sharing options...
Lara Posted December 12, 2005 Share Posted December 12, 2005 Yup, it could not really be called objective, too many assumptions have to be made. The only figures you can take for real are if you rolling road the unit before modification and then compare the difference.I have a GTECH performance meter that claims to be able to be able to "calculate" the flywheel figure using inertial measuring techinques, haven't had a chance to play with it yet but it will be interesting to compare with the rolling road figures I have. If you have a top notch rolling road (as I have ) it will measure wheels power, transmission losses, therefore engine power can be correctly measured, and correct torque etc, and if it is setup to DIN 70020 as it should be, it will take atmospheric pressure / temp into account, my rolling road has an atmospheric chamber as well so (as you can see from the graph) the pressure and temp are controlled to reduce possible errors to "0". The rollers on my unit actually measure power loss by running up the transmission after the power test, so this is "actual" and not guessing. And believe me it can change dramatically between vehicles I do all my tests on my car locked in 3rd with Torque converter electronically locked, 3rd is close to 1:1 on my auto trans. There are some variables in these tests from one type of transmission etc to another, ie. the engine must be disconnected from the engine for trans loss measurements so this must be done in neutral with an auto, this ovcourse will give a little less drag than actually "in gear" but with testing this has proved to be only 4-5% of the total power loss so I am not going cry about 1 or 2kw. But it is true that the only absolutely accurate way of measuring engine power is on an engine dyno. I have tried these calculating computer / gps units and found them absolutely and totally inaccurate for anything other than comparisons on the same vehicle in the same conditions, they do not in any way relate to the rolling road tests. If anyone was considering this route. Regards, Lara. Quote Link to comment Share on other sites More sharing options...
will_warne Posted December 12, 2005 Share Posted December 12, 2005 If you have a top notch rolling road (as I have ) it will measure wheels power, transmission losses, therefore engine power can be correctly measured, and correct torque etc, and if it is setup to DIN 70020 as it should be, it will take atmospheric pressure / temp into account, my rolling road has an atmospheric chamber as well so (as you can see from the graph) the pressure and temp are controlled to reduce possible errors to "0". The rollers on my unit actually measure power loss by running up the transmission after the power test, so this is "actual" and not guessing. And believe me it can change dramatically between vehicles I do all my tests on my car locked in 3rd with Torque converter electronically locked, 3rd is close to 1:1 on my auto trans. There are some variables in these tests from one type of transmission etc to another, ie. the engine must be disconnected from the engine for trans loss measurements so this must be done in neutral with an auto, this ovcourse will give a little less drag than actually "in gear" but with testing this has proved to be only 4-5% of the total power loss so I am not going cry about 1 or 2kw. But it is true that the only absolutely accurate way of measuring engine power is on an engine dyno. I have tried these calculating computer / gps units and found them absolutely and totally inaccurate for anything other than comparisons on the same vehicle in the same conditions, they do not in any way relate to the rolling road tests. If anyone was considering this route. Regards, Lara. Lara, you totally right. That's why I'm using the people I am; I'll get decent figures including the transmission loss. I'm not sure how I'll do my test on the rollers as I can't lock out in top (the only gear with effective torque convertor lock up) so it'll have to be probably 3rd. However, I'll leave that to the experts. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted December 12, 2005 Share Posted December 12, 2005 I have tried these calculating computer / gps units and found them absolutely and totally inaccurate for anything other than comparisons on the same vehicle in the same conditions, they do not in any way relate to the rolling road tests. If anyone was considering this route.Regards, Lara. I'd no idea anyone had used it for this application before - it's just a piece of software I've written to produce a power curve from some accelerations so I can get rough percentage power/torque guesses for adding a snorkel, altering the fuelling etc. I'd be interested in seeing how it compares to a real road actually - yours sounds pretty well specced Lara, the University one I've played with is used for emissions testing rather than performance measurements and they charge £3000 a day - on contract! JB Quote Link to comment Share on other sites More sharing options...
Lara Posted December 13, 2005 Share Posted December 13, 2005 Hi Turbo, In the states they sell many types of units for calculating power based on accelerometer readings and GPS tracking etc and these vary from 200$ to 5000$ depending on the complexity etc. They all depend on user inputs and a certain amount of guesswork, you can fine-tune the units by an amazing amount by intricate accurate measurements etc but CD is a major factor and about the most difficult to measure without a full size rolling road wind tunnel, Even Williams don't have one of these! They are however very good for doing the sort of stuff you are using it for, e.g. Comparison work of systems on the same vehicle. FYI. I charge +- 1500 Euro / Day for my rolling road including a man to operate it. Perhaps I should change my prices Lara. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted December 13, 2005 Share Posted December 13, 2005 It's not hard at all to estimate the c.d. using a coastdown, surely? That's what I've done. Neglecting any wind speed (2 runs in opposite directions?) you'd not be far out although the numbers I'm getting seem on the high side to me. As you say, it's good for quantifying "better/worse" instead of subjective guesswork though. You'd be very lucky to have the kind of emissions equipment the Uni operate - that's what really earns them the money on their road. Quote Link to comment Share on other sites More sharing options...
Lara Posted December 13, 2005 Share Posted December 13, 2005 The problem with using the coast down method is that you are measuring total losses, including tyre scrub, rolling resistance, transmission losses, and drag etc, etc and you never know exactly what % is what, the problem then arises that power losses are generally fairly linear and drag is certainly not linear, so it is difficult to calculate anything other than comparisons from this data. HP in my experiments was nowhere near but comparisons were very relevant. My emissions stuff is probably way off of that used by your uni by the way. "Unfortunately" Regards, Lara. Quote Link to comment Share on other sites More sharing options...
will_warne Posted December 13, 2005 Share Posted December 13, 2005 FYI TC, I was quoted £85 for the first hour then a slightly reduced rate for my time on the rollers with an operator who'll tune the vehicle. Not a bad price IMHO. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted December 13, 2005 Share Posted December 13, 2005 The problem with using the coast down method is that you are measuring total losses, including tyre scrub, rolling resistance, transmission losses, and drag etc, etc True - I've just used a model which gives a linear and quadratic coefficient to model it all. I'm not fussed what % is what, I just need to know that at 20mph it's 50/50 and at 40mph it's 20/80, for example. The difference between the coast and the powered run is the engine, regardless of how much is, say, rolling resistance against tyre scrub. As you say, it's still ideal for "before and after" (can I say that?) comparisons. Quote Link to comment Share on other sites More sharing options...
headhunter Posted December 16, 2005 Share Posted December 16, 2005 Just received this note from Prinz Mortens in Holland who supplied my 2.8TGV, thought it might add some perspective to the discussion. John Dear Madam, Sir (how very PC!!!) All of you know the 2.8 TGV engine, and we think everyone is impressed by its performance in the Land Rover. So are we. We were even so impressed and confident that we have a car fitted with this engine for the famous Paris Dakar rally, starting the 31st of December this year. The car originally was equipped with a V8 ,however the driver, Raoul Jacobs, wanted to have a reliable, strong engine with a lot of torgue. He has driven many rallys and knows what he wants. Therefore he choose the 2.8 TGV. Throughout the last couple of months we have fit the 2.8 TGV in the Bowler. The engine was tuned by Allisport in the UK and is giving now 170 HP and 420 Nm. On the website www.dakar2006.nl you can follow the day to day performance the perform. Live updates will be given on a daily basis. Quote Link to comment Share on other sites More sharing options...
JST Posted December 24, 2011 Share Posted December 24, 2011 so, when tunning this engine, is it the same format as a tdi? (as detailed in the tech forum) what about the turbo, doesnt i have a different wastegate arrangement? Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted December 24, 2011 Share Posted December 24, 2011 the tgv engine has a vnt on it, so no wastegate. And yes, same theory as a tdi because it still uses the VE pump. Quote Link to comment Share on other sites More sharing options...
JST Posted December 24, 2011 Share Posted December 24, 2011 vnt or vvt? Quote Link to comment Share on other sites More sharing options...
JST Posted December 24, 2011 Share Posted December 24, 2011 vnt you are right, just googled it. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted December 25, 2011 Share Posted December 25, 2011 vnt or vvt? same thing,could be a vgt if you really wanted. Quote Link to comment Share on other sites More sharing options...
JST Posted December 25, 2011 Share Posted December 25, 2011 variable nozzle or variable vane are two different things. i thought the latter the vanes rotated and the former the nozzle axial width changed both depending on boost. Quote Link to comment Share on other sites More sharing options...
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