[flash]

most of the part throttle mapping is done. i'll finish that tomorrow, and then get the WOT on monday.



going very nicely

Partial Post: Please Login or Register to read the full post.

[flash]

well, it's all buttoned up and restored to the standard kit format so i can get "before" readings, and then reinstall everything for stage 2 runs. i am only booked for 2 hours tomorrow (not my fault) so i have pre-written a few files so i can try a couple of things and use less time setting up. i'll come away with most everything mapped. any tweaks i make after that won't affect output power or anything like that, and would only be to clean up any anomalies.



now, if it only weren't going to be over 100 degrees out, in a black car with no air conditioning, and if only i had the time to fix the suspension setup to something that actually works. the setup it has now is rattling my teeth and bruising my kidneys. oh well. i'll get that done next week.



time now for a cold adult beverage.

Partial Post: Please Login or Register to read the full post.

[DaveN]

100 Degrees out! Here I sit like some low class plebe suffering in 68ish (my imperial isn't so good) and you have the gaul to complain. Either that or I am

jealous? Back to the bar and damn you Southerners :-P

Partial Post: Please Login or Register to read the full post.

[durtkillon]

The garage is clean, all projects complete. I'm itchy for a thrill delivery mechanism. I've been contemplating building up a motorcycle. Perhaps this will stave my two wheeled desire for a while. Perhaps....

Partial Post: Please Login or Register to read the full post.

[flash]

lol - durt - i'm still waiting to hear back from you on what is going on with your car



dave - i wish it were 68. i hate hate the heat. when it gets to 80 i run inside

Partial Post: Please Login or Register to read the full post.

[flash]

all packed up and ready to go. i'm off in about an hour.

Partial Post: Please Login or Register to read the full post.

[DaveN]

Whoohoo! I'm just going to leave this thread open all day and set up a script to keep hitting refresh for the next 8 hours <img src="/forum/images/smilies/968/tongue.png" class="smilie" alt="" />

Partial Post: Please Login or Register to read the full post.

[flash]

lol - well, i'm back. the good news is that i am pretty sure i'm going to get there. the bad news is that i did wring just about everything out of the kit the first time. i solved 2 problems but created a third. i am going back on friday to try some different components that i was hoping to avoid.

Partial Post: Please Login or Register to read the full post.

[flash]

today is all about going back to the drawing board and seeing what i can do to solve the fueling problem. there just isn't enough fuel available with the stock injectors, regulator, and pump, to make more power.



i can't change the injectors, as that would create problems with emissions testing, and too many people have to go through that, and more will have to go through it as the years go by.



so, i get to play around with regulators and see if i can add enough to make the power i want. it's all over 5500, so i have a couple of options.



in the end though, i may well be able to make more power up to 5k, but i may end up exactly where i was from there up.



we'll see. in any event, the kit is turning out to be a LOT more work, and more parts and all that, than i had hoped for.



lol - i could just slap some stuff together though, and send it out and let others find out the hard way......................kidding. i'll bail on this before i do that

Partial Post: Please Login or Register to read the full post.

[bombfactory]

>>> the kit is turning out to be a LOT more work ... than i had hoped for <<<



You DO realize this is a 968 you're working on! :-)

Partial Post: Please Login or Register to read the full post.

[flash]

lol - yeah - no worries.



it's a really good thing that i did as much testing and development on the kit as i did. that data has proven to be very helpful in determining what the best solutions to my current problems would be. knowing the limitations of certain things allows me to plot the course much more easily

Partial Post: Please Login or Register to read the full post.

[94SilverCab]

Just send everyone a pulley and a wider belt...Boom, Stage II perfection.... <img src="/forum/images/smilies/968/glare.gif" class="smilie" alt="" />



Jay

Partial Post: Please Login or Register to read the full post.

[Eric_Oz_S2]

The lack of fuel is not surprising considering my turbo injectors are maxed out at 6500 rpm with 7 psi, and they flow a lot higher than the 968 ones.

Partial Post: Please Login or Register to read the full post.

[tamathumper]

And a box of knurling for the pulley. Yeah, a *whole* box of knurling. <img src="/forum/images/smilies/968/biggrin.png" class="smilie" alt="" />

Partial Post: Please Login or Register to read the full post.

[DaveN]

Injectors definitely max out, and ask me how I can know! Look on the bright side, if Bob can't figure this out we can change the title of the thread to "I found another 700.00 in the bank account" :-( :-P

Partial Post: Please Login or Register to read the full post.

[MB968]

Does our ECU learn from how the engine is operating? If you have a set of injectors that are on the high side of flow, or ones that have with age started to flow less, will it treat this as the new norm via a "learn" mode? If so, then you could use a slightly higher fuel pressure to up the flow of the injectors, reset the ECU, and let it relearn the new norm.

Partial Post: Please Login or Register to read the full post.

[flash]

no

Partial Post: Please Login or Register to read the full post.

[Eric_Oz_S2]

The actual answer is "sort of". The ECU will adjust the PT fuel maps by 'remembering' the changes to injector pulse duration to achieve stoich at part throttle. The <acronym title='wide open throttle'>WOT</acronym> maps are then actually 'delta' maps compared to stoich. So what this means is the <acronym title='wide open throttle'>WOT</acronym> maps will add the same amount of additional fuel over stoich - BUT there are two problems with this. One is that for a supercharged engine you need more fuel than NA. Two is the <acronym title='mass air flow'>MAF</acronym> is likely to be flowing beyond or near its limit - so the engine would not know how much additional air is being inducted. It appears the <acronym title='wide open throttle'>WOT</acronym> maps do not 'fully' utilise the air flow information from the <acronym title='mass air flow'>MAF</acronym> either - rather it relies on a simple 2D RPM vs Fuel trim map (<acronym title='wide open throttle'>WOT</acronym> Fuel map).



Also, when you disconnect the battery, the ECU must relearn. This results in horrible driveability and stumbling for 20 mins until the ECU has adapted.



A rising rate regulator will add fuel relative to boost so it can scale up these maps, but it will not be able to achieve a 'flat' AFR, as the volumetric efficiencies will also change with forced induction. Hence you will get parts of the map that will be to rich. Hence you still need to adjust the maps. Also, the idel fuel maps work differently, and do not adapt very well to bigger injectors.



In summary, the only way to get it working 100% correctly is to retune the fuel maps. 'Other' kits don't do this and therefore have non-optimal AFRs.

Partial Post: Please Login or Register to read the full post.

[flash]

that may be the case with the S2 ECU, but it is not the case for the 968 ECU



the 968 ECU only remembers for 1/2 second. then it forgets. it does that every half second though.



as for the maps, there are actually quite a few WOT maps, and only three of them are 2D. there are a number of 3D WOT maps for the 968.



the ECU on the 968 does not "reset" when you disconnect the battery. it does reset fault codes when you disconnect the ECU. not sure why. there is no running condition change though. i did it a few times just monday.



the fuel pump only goes to 58lbs, so there is a limit to what any fuel pressure changes can do.



eric is right though about the need for mapping. that's why this takes so long. there are 142 maps for the 968. this is due to the 3 applications (US, ROW, non-cat). so, only a third of them are used for each car, but there are still quite a few that need work for each setup. i have to make changes in about 10 of them.

Partial Post: Please Login or Register to read the full post.

[Eric_Oz_S2]

There are short and long term adjustment maps (this is common to most ECUs). The short term is used for fine tuning adound lambda =1 - ie it learns the steps needed to best target stoich at different loads and rpm. The long term adjusts around engine condition and will be utilised with injector changes or engine problems. As these maps are held in RAM, they are normally zero'd when power is disconnected from the ECU, the time this takes is dependant on the charge held within the ECU power supply. These are not the maps in the EPROM - you can't change these as they are learned by the ECU as 'trim'. Perhaps the 968 is different in this regard as you suggest.



Interesting the 968 has 3d <acronym title='wide open throttle'>WOT</acronym> maps - haven't heard that before. Looking at the maps I have only seen the 2D <acronym title='wide open throttle'>WOT</acronym> maps in the 968 code.

Partial Post: Please Login or Register to read the full post.