...we started the race and right from the start Zikas started to pull away... at the end of the street he was ahead by some 2 car length, this can't be right considering the mods i have on my car compared to his car:
MMamdouh,
Removing your resonator and cat with only modifying spark plugs on the engine will only result in lose of power and poor fuel economy.
Like Domwoo said it's got to have back pressure.
Imagine yourself drinking water out of a glass by sucking on a large straw and comparing it with small straw.
It's gonna need more effort to suck the water out using a large straw. Of course if the straw is too small, it too is gonna take more effort too due to a lot of restriction. It just has to be the right size. The exhaust setup from the factory will be the ideal size.
Unless your car is turbocharged, you will need some backpressure.
Do you have an O2 sensor after the cat in Egypt? If you do, what did you do to it?
in here we got one CAT and one O2 sensor at the header... the exhaust piping is the OEM size all the way and i didn't do anything to the O2 sensor... after reading many reviews i can see that a dirty O2 sensor can make the car run rich, could that be my problem?
again when it comes to gas flow and all i think removing the CAT and resonator helps high end HP and hurt low end torque... the question is: is it suffecent to make such difference? i mean if i am behind by 2 car length in the low gears does this mena i'd win hands down when we go all the way up to 4th and 5th gears with RPM going up to 5500~6000?
I think that O2 sensor doesn't matter during race (high acceleration) because injection works in open loop. In this case rich mixture only help accelerate. You have made to much changes in intake an exhaust. Bad tune up intake and exhust deteriorate power of engine. Here you can see how can change torque diffferent types of filter (translation: stozek-cone filter, seria-stock) http://www.chojnacki.com.pl/wykresy/wykres.php?id=18. With this configuration you lose too much torque at low rpm and not earn enough at high rpm.
i am sure my car is losing torque... today i cleaned up the spark plugs,TB and intake along with an oil change and usualy in the old days that would make the car fly off the road but after all that work today it seems no differnt at all.
i also cleaned up the O2 sensor with GUNK carb cleaner (leaves no resedues) but still no changes to performance whatsoever.
the car felt like it was losing a little power after 2 or 3 weeks of the timing belt replacment... actually right after the belt replacment the car was at top form then 3 weeks later or so the problems began.
it started out by lille hesitation in idle, a flat spot in the throttle at the begining of 2nd gear and now i got a little "kangaroo" responce at low rpms specially in 2nd gear and now with the steel 14" rims and 185/60/14 tires i can't very hardly squeal my tires at take off.
also now i can feal the load of extra passengers in the car as well as going up hills... that was nevewr a problem in the older years or at least not that noticalble plus the car sputters as hell if i tried to drive it with the engine still very cold... again in the older years it didn't do that.
i am not sure guys... i have replaced almost every thing that is performance related but the coil pack... only think i can think of is the current timing belt is a little expanded and the timing is slightly off... this would explain loss of power and idling hesitation... if it is not than that then i must have a busted engine or so but i don't think i managed to bust my engine in 75000 kms specially when the car is not rattling or burning oil at all.
any help will be very appreciated guys as i am getting desparate on this... its a shame to be very knowledgable when it comes to daewoo yet i can't tune my own car.
well have you checked your wires? clean all the ground points, grounding kits, i need to clean out my grounding points on my car right now, also what type of wires do you have, rember bigger doesnt mean better, the car has to be able to produce a large enough spark to travel too it. the pontiac guys right now dont even touch anything larger than stock because they get issues even on the gtp (supercharged).
have you looked at sluge build up in the engine? dirty injectors and filters? egr leak? vacume leaks?
when all fails try washing EVERYTHING, i have like 2 pounds of brake dust on the inside of my rims before, it made a small diffrence washing them.
you can try waxing it to cause a low friction surface.
or you can try rice by adding a large wing and some stickers.
Put the stock air box back on and give it another shot. I did some testing with a cone and found out that low end torque went away with it on. I started putting tape on the filter until I found a sweet spot and found that by the time I got the low end torque back I only had about 2 inches of the cone that was not taped off. I liked the cone because it sounded cool but will kill your performance and gas mileage.
Higher octane gas will not help either, your car is made for 87 and cannot take advantage of 90 or 92. The only way to effectivly use higher octane would be to run higher compression.
chronoti wrote:well have you checked your wires? clean all the ground points, grounding kits, i need to clean out my grounding points on my car right now, also what type of wires do you have, rember bigger doesnt mean better, the car has to be able to produce a large enough spark to travel too it. the pontiac guys right now dont even touch anything larger than stock because they get issues even on the gtp (supercharged).
have you looked at sluge build up in the engine? dirty injectors and filters? egr leak? vacume leaks?
when all fails try washing EVERYTHING, i have like 2 pounds of brake dust on the inside of my rims before, it made a small diffrence washing them.
you can try waxing it to cause a low friction surface.
or you can try rice by adding a large wing and some stickers.
i got a grounding kit that is recently installed and all grounding points were checked so it can't be a grounding problem.
my spark plug wires are OEM and in good condition... only 3000 kms on them
engine is clean inside and outside, injectors are 10,000 kms old and i regularly use injector cleaning products, no vacuum leaks at all.
mrbnew wrote:Put the stock air box back on and give it another shot. I did some testing with a cone and found out that low end torque went away with it on. I started putting tape on the filter until I found a sweet spot and found that by the time I got the low end torque back I only had about 2 inches of the cone that was not taped off. I liked the cone because it sounded cool but will kill your performance and gas mileage.
Higher octane gas will not help either, your car is made for 87 and cannot take advantage of 90 or 92. The only way to effectivly use higher octane would be to run higher compression.
now thats confusing... if adding a cone filter make us lose torque so why do we experiance performance enhancment?? does it increase HP on the expence of low end torque? it is not a big deal to put back the OEM airbox and resonator but i got to understand what a cone filter does in real life... does this mean that guys with SRI suffers the most when it comes to low end torque??
i am now running octane 90 on my car and frankly the 92 was doing better... car felt more smooth and responsive than what it is now.
still suspecting timing... do you think it can be that??
High flow air filters help more in larger engines at higher rpm. I am not trying to burst anyones bubble, just sharing my personal experience with my lanos 1.6 compared to my small block chevy 350 I have in my truck. I put a cone on that and the difference was night and day so I thought the same would apply to the woo.... not so much.
Have you checked your timing? If a 1.5 sohc is interferance engine like the 1.6 you would probably know if it was off by the noise of the valves hitting the pistons.
you won't notice a single difference on the cone sizing on a 1.6 due to the VGIS system... you are experiencing a placebo. the pulse-wave seperation in the 1.6 stayes contained inside the VGIS system... it's designed to control the "reverb" of the engine intake valves... so ajusting the filter and intake piping to the manifold is a useless struggle aside from sinply making the path have less resistance.
so due to the lack of VGIS on my engine and adding a cone filter not to mention that i have already removed my resonator some 2 years ago gave me a bit more HP on the expence of torque.
my 1.5 SOHC is an interference engine but will one notch off on the timing belt cause the valves to hit the pistons? i think not... also i think this explains the mild vibration i got at idle (spark plugs, wires and injectors are fairly new).
will a bad O2 sensor cause loss of low end torque? i cleaned mine using GUNK carb medic and nothing changed performance wise so either it was already working properly or dead byond repairs... i guess i will try to check it using an air/fuel ratio menter... can one test O21 sensor segnal using a standard issue mulimeter??
got this peice of info while checking my 13" to 14" rim upgrade post:
Chippy wrote:Just go for it, the handling benefits will out weigh the extra weight. The only time you really have to worry about rotating mass is on acceleration from a dead stop, and bringing the car to a stop again. Once it's rolling, you won't really notice a difference, except up a steep hill.
i guess this could be added to the slow acceleration i am facing against a stock lanos... 1.25 kgm extra rim/tire setup + 0.5 kgm extra on the brembo rotors per front wheel, got to make a difference even if it is little... right?
