Should I get a Warranty -- How many issues have you had?

grandpawmoses

Long version (and maybe a little overly stated):
When you modify an exhaust or intake to be less restrictive, you cause the engine to run leaner (and hotter). The wide band O2 sensors will adjust the ECU to accommodate for this a little but a retune really is needed or you could ruin an engine. The dealer and factory rep is going to look for a reason to deny any "big ticket" warranty repairs.

Not speaking of Nissan but my personal experience with Harley-Davidson: If a bike comes in for an oil change or whatever and the mechanic notices a non Harley modification, the dealer can "flag" the bikes VIN and it can be denied specific warranty repairs in the future. Now the Magnuson-Moss warranty act does protect you because it requires the modification to be directly associated with the problem.

njobe89

Thanks for the quick educational lesson, didn't know that and of course the dealer would try to find the smallest thing so they don't have to pay, bastards... i already have my exhaust on now and getting the intake put on this weekend and i wasn't thinking of getting it retuned, but i guess i need to now lol

grandpawmoses

If, after the exhaust and intake mods, everything seems to run okay, there is a cheap way to tell if you're running too lean. Warm up the car, Run it hard for about a mile, shut it down & coast to a safe stop, immediately remove a spark plug and check its' insulator color. Black is too rich, white is too lean, and tan is what you want to see. If it's white, get it tuned immediately.

For what it's worth
Not to justify the cost of a tune but it involves a lot more than just getting the air/fuel ratio to a stoich AFR(about 12.7 AFR for 91+ octane fuel in a naturally aspirated engine). It also involves timing, spark knock retarding, cold cranking enrichment, acceleration enrichment, and deceleration enleanment to name a few. The AFR is adjusted for each cell in a table of throttle positions against engine RPM's. This is done for each cylinder too. The dyno technician really needs to know his stuff and will still take over a dozen wide open throttle runs even with todays computer assisted tuning software. Also, get a copy of the tune or "map" on a thumb drive & keep it. It'll save you some money if you ever need to reflash your ECU.

njobe89

i'll be going to z1 motorsports, everyone seems to agree they are well trusted, but i will ask for that when i go and see them.

is this the general rule for every car or just the Z's? i had a rsx-s before with some bolt on and never did a tune on it or anything and it went fine for the time i had it.

grandpawmoses

Just general for ECU controlled gas engines. Older carbureted engines were adjusted with modifications to the carb jets.

More worthless info
Most all water cooled engines (cars and bikes) have wide band O2 sensors and they do a decent job of telling the ECU to up the fuel with minor exhaust and intake mods. (A water cooled engine has a narrow band of engine temperature and can use a wide band O2 sensor.) They still need adjustments to their "map" (or tune) for timing, etc. to get the maximum horsepower. ("map" should not be confused with "MAP" or "Manifold Absolute Pressure" which is another factor the dyno tech has to deal with.)
Air cooled motorcycle engines have a very broad band of operating temperature and most use a narrow band O2 sensor. A tune is almost always needed with even small air flow mods. I've closely followed Harley Davidsons' transition to water cooled engines on their touring bikes and believe it was an inevitable move by HD. With stricter EPA restrictions looming, it was the only route.

mattimus

This is false. An exhaust doesn't blow an engine. They would lose in court. They may give you **** about it, but if you stick to your guns I would say its not a problem generally. I know a lot of people with STis (my previous car) that have had an engine blow with an exhaust and it was covered.

grandpawmoses

I appreciate your input but let's get this back on track. I've attached a picture of piston damage done by a lean engine. This is the engine failure I'm referring to, not blowing an engine.

Attached Images

169500d1236892930-98-zr-500-melted-piston-piston_001.jpg (90.9 KB, 14 views)

L33T Z34

I would drop the $$$$ on the Xtended warranty if u don't work on the Z urself.
For the following reasons:
1) oil consumption
2) oil overheating
3) plastik CSC failing
4) rear diff silicone bushing tearing
5) I could go on, but I refrain....
The Z is a cost-cutted POS, but w/the right mods and time dropped into it...it can become a fun reliable daily.

mattimus

I guess I shouldn't speak in generalities. Not all of them were blown engines. there were other types of engine failure from ringlands to piston failure. Pretty much everyone of these experience i've seen where the person had a tune the warranty claim was denied.