j9fd3s

some of them need a laptop, but some of them can out put a 0-1v or 0-5v signal so you can input it right into your ecu, saves you from having 2 different datalogs



mike

MaTT_FoULk

Excellent thread for someone who just purchased a Haltech. Sticky it maybe?

j9fd3s

I can answer this..I think.



11:1 isn't universally standard for engines, 11:1 is quite high for a stock engine.



Higher compression produces more power for N/A engines which is why Honda Type R engines are approximately 10:1 I think (may have remembered wrong) mind you that's a lot for a 4 cylinder engine.

When you want to highly tune a N/A piston engine you buy high compression/lighten pistons along with valves so you don't get valve float when you're revving extremley high now. Different degrees in Cams also have some effect I forget though. Tuning N/A is extremely expensive because parts are made extremely quality due to amount of work they have to do. Which is why you see so many Turbo Charged Type R's.





In fact when you turbo charge Type R's the reason why you have to run so low boost is because the engine has such high A/F ratio in the first place. Makes sense?



Keeping in mind that high compression motors plus lots of boost creates crazy power but you engine has to be able to handle that.



That's also why a while back someone told me S4 TII engines are better to highly modify than S5 TII engines even though S5 TII has more BHP stock. This is because S4 TII engines stock have a lower A/F ratio, and you can boost higher without being afraid of detonation.

Lower A/F ratio stock gives you less BHP, but on the S5 the engine is has higher A/F ration so it creates little more bhp stock.



I think this is right, please correct me if it's wrong. [/quote]

we're talking about air fuel ratios, not the compression ratio of the engine, thats a whole 'nother ball of wax



mike

rxrotary2_7

not nesecarily true from my understanding.

i did not know how to put it to words before, but recently Matt (hitman) had a good explination of this on the haltech mailing list. it went something like this...

the same amount of fuel being combusted to make up a certain a/f ratio will have a diferent egt reading due to timing. if you have the timing advanced the heat is going to be held in the motor heating it (internals of motor) up. if timing is to far retarted, the internals will run cooler, but the heat will be seen in the exhaust (higher egt's) you need to find the happy medium for your motor.

did my explaination of HIS explination make any sence? LOL

dynamite kid

Lets say i have a base map and have the fuel tuned a bit rich for safety,how would i tune timing for every load and rpm with and without a dyno,Thats what i dont understand and its what i need help on.I know with the average t04e on a 1990 rx7,at 15psi timing should be around from 38 degrees tapered down to 13-15 degrees advance So how do we tune for vaccum to 3,4,5,6,7,8 all the way upto 15 psi for every rpm point.





Thanks

Fd3BOOST

I imagine that this is where a data log would come in handy.

j9fd3s

the engine will make pealk power when you have the timing in the optimal spot, however it can be dangerous to keep advancing the timing.



you also want to be watching the egt's they need to stay in a range under full throttle

Mark'sMazda

alright, tuning the fuel seems easy enough, as their is a set AFR you are aiming for.



What about the timing? What EGT's are in the "sweet spot"? how many degrees should you move at once? one? I understand you advance the timing from idle, to spool rpm, than start retarding it. after max torque? This is because the cylinder pressure is at the highest between full spool rpm, and max torque, it then begins to drop. correct? Since I have no dyno, I don't know my max torque, so is their any base lines for, stock port, stock turbo, street port?

Mark'sMazda

I realize their will be lots of varibles, whare the probe is placed, motor porting?, exhust systems, and so on, but in genral what temps should I be looking for?



I hear of people putting their EGT probes in the manifold, just after the turbo, and in the mid pipe. Which is best? I would think manifold, but wouldn't the turbo retain extra heat, throwing off the guage? With widebands it's said they should placed x inches after the turbo. is their anything simular for EGT's?

dynamite kid

Timing should be retarded the most at the peak tourqe then can be raised a little to keep the egt stable after peak tourqe.As for finding tourqe only way i know is a dyno.Maybe you can check out the new gtech pro it measures dyno and horsepower but i would set it up on a friends stock car to see how accurate it is and check the factory specs for that car somewhere to see if its worth using.I hope someone chimes on for us who live in a tuneless city..