Muffleman Posted July 2, 2007 Share Posted July 2, 2007 Been thinking about this over the weekend. I was taught to map a car using steady state tuning on a dyno, not on the road. I'm only talking about ignition here. As we dialled in the ignition advance at various low load sites, you could see the torque effect in realtime on the dyno. Peak torque arrives generally in a range before det starts to occur, and I was taught to aim at MBT so as to steer well clear of any det. Torque generally falls away well before det starts to set in. So how do you do it on the road ? Have someone drive whilst you have det cans on, dial in the ignition until you start to hear det and then back the ignition off ? How many degrees ? Link to comment Share on other sites More sharing options...
Alex Posted July 2, 2007 Share Posted July 2, 2007 Yes generally...mapper is the passenger, the driver just does what he's told and looks out for the cops! Ideally you should get to a known state on a dyno then fine tune on the road. Link to comment Share on other sites More sharing options...
Muffleman Posted July 2, 2007 Author Share Posted July 2, 2007 Yes generally...mapper is the passenger, the driver just does what he's told and looks out for the cops! Ideally you should get to a known state on a dyno then fine tune on the road. Totally agree, road mapping just seems a bit close to the wind with regards to det. Maybe I'm a dyno snob Link to comment Share on other sites More sharing options...
Ryan.G Posted July 2, 2007 Share Posted July 2, 2007 The way i normally work is to tune a car on the road and then for the silly speed stuff required at the end leave to when its on the dyno. Or if owner is happy and its quiet then do on road I have yet to find a dyno that can simulate the road load well enough to not need a tweak on the road and a car will always run richer on a dyno due to the airflow being alot less. I have seen cars that have been tuned by others on the dyno to 11.6 and then when on road run 11.8. road mapping just seems a bit close to the wind with regards to det. Maybe I'm a dyno snob Could you explain why. Trust me you hear det alot easier when on the road than when in a dyno cell I bring in the ignition slowly until i hear pre det than knock it back 1 degree in that load cell. As soon as i hear any pre det the hand goes up and the driver backs off. Also how many engine have you heard of going bang on the road while mapping against on the dyno Link to comment Share on other sites More sharing options...
Alex Posted July 2, 2007 Share Posted July 2, 2007 Dyno cells are hot and the loading will never be the same as the road. Link to comment Share on other sites More sharing options...
Chris Wilson Posted July 2, 2007 Share Posted July 2, 2007 You map 90% on the dyno (and MUCH preferably on an engine dyno, at the very least a hub type wheel dyno), and trim cold start and acceleration trim, maybe very light throttle cruise sites, too, on the road. mapping the whole caboodle on the road is for dreamers and those with a desire to blow the thing up. It can be done on the road, but it's a very slow, potentially dangerous, and messy business. Link to comment Share on other sites More sharing options...
Muffleman Posted July 2, 2007 Author Share Posted July 2, 2007 Believe me mate, not 'knocking' road tuning (dya like what I did there ) just looking to learn I'd be happy to road tune as there is a lot more availability of road than dynos, and roads are a lot cheaper too So you get to pre-det knock and bring it back one degree. Is that enough of a safety margin ? And is that the best torque point ? Generally, when you have road mapped and then get to the dyno, do you find you take ignition out ? Link to comment Share on other sites More sharing options...
Chris Wilson Posted July 2, 2007 Share Posted July 2, 2007 You map on the dyno, then TRIM on the road. The torque and power graphs should show the approach of ignition det, putting a load of advance in, running off boost, should allow a trace of the knock sensor outputs to be analyzed to see what "det" actually looks like on that engine / sensor combination, with minimal risk. Link to comment Share on other sites More sharing options...
Muffleman Posted July 2, 2007 Author Share Posted July 2, 2007 You map 90% on the dyno (and MUCH preferably on an engine dyno, at the very least a hub type wheel dyno), and trim cold start and acceleration trim, maybe very light throttle cruise sites, too, on the road. Well that's what I was taught and so was curious how cars are road mapped. Link to comment Share on other sites More sharing options...
Ryan.G Posted July 2, 2007 Share Posted July 2, 2007 I Agree Chris mapping on a engine dyno is the best way forward and is alot quicker but the rest of what you said i dont agree with one bit espically your wording of "Dreamers" Some of the best tuners in the world i know from Motec pref to map a car on road over a rear wheel dyno. In a dyno cell everything is alot hotter and the load is totally different to what the engine will experience on the road. The car will always run slighty richer on a dyno due to airflow issues and you will never be able to get in as much advance due to the temps being greater. This is where a standalone is favoured due to the air temp correction pulling timing at set points in the map where the temps have risen. A mixture of both i find works best but some customers do not like to have to pay £75+ for hiring the dyno for an hour. And i would like to add again, how many engine do you hear about going bang when mapped on the road insteed of dyno. I dont doubt your knowledge chris with regards engines and suspension but i for one dont agree with 70% of what you have said in your first post Link to comment Share on other sites More sharing options...
Muffleman Posted July 2, 2007 Author Share Posted July 2, 2007 Some of the best tuners in the world i know from Motec pref to map a car on road over a rear wheel dyno. I know Fraser does. Link to comment Share on other sites More sharing options...
Ryan.G Posted July 2, 2007 Share Posted July 2, 2007 So you get to pre-det knock and bring it back one degree. Is that enough of a safety margin ? And is that the best torque point ? There alot of things which you have to take into consideration with ignition timing as with colder temps you are able to get more ignition timing into a engine so pulling 1 degree back is not all that goes into a safety margin. The afr and lots of other factors effect it. They are many great books out there all about it and course espically at motec where i started my training. Generally, when you have road mapped and then get to the dyno, do you find you take ignition out All depends on air temp, airflow etc but normally its pretty spot on due to me setting up the air temp correction options Link to comment Share on other sites More sharing options...
Ian C Posted July 2, 2007 Share Posted July 2, 2007 I think this'll be an agree-to-disagree thing I know it took me many many iterations of my own personal car's map to get it good and get a map structure in place to use as a base. Many miles, many hours, many litres of fuel! As CW says, it's a slow process. Once the base is in place, fitting it to another Supra is a relatively short job, though. That's mainly the reason I've never mapped a non-Supra - I could, but the first time would take aeons as I carefully and slowly got the feel of the thing. Oh, and I back off 5 degrees as the 3 degrees before the first spings of det don't give any more power, and another 2 degrees to cover dodgy fuel or a hot day or a intercooler problem or whatever environmental factor, and the extra couple of bhp those two degrees of timing would net you aren't going to be that noticeable when you've got a T61. Just my personal "coward" approach to mapping -Ian Link to comment Share on other sites More sharing options...
SimonB Posted July 2, 2007 Share Posted July 2, 2007 The problem with mapping on road is that you can't set the ignition timing to produce max torque. All you can do is advance it until it dets and then back off a bit. It may be that you advance it past the point of peak torque, there's no way of knowing. Link to comment Share on other sites More sharing options...
Ryan.G Posted July 2, 2007 Share Posted July 2, 2007 Oh, and I back off 5 degrees as the 3 degrees before the first spings of det don't give any more power, and another 2 degrees to cover dodgy fuel or a hot day or a intercooler problem or whatever environmental factor, and the extra couple of bhp those two degrees of timing would net you aren't going to be that noticeable when you've got a T61. Just my personal "coward" approach to mapping I wouldn't say coward approach ian i would say thats about right on a emanage as its doesn't have the control of standalone. On all pm's i have had about piggyback mapping i have sent your way as well due to you knowing more about how the stock ecu fights the piggybacks Link to comment Share on other sites More sharing options...
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