Kevinsino

I've got an '88 'vert and have two questions:

1. With the size rims I have (18"--see picture), how off is my speedometer and odometer? I know they have been calibrated for the stock 16" BBS rims, but not for my 18's.

2. When I 'open it up' on the road, as soon as I shift I hear what sounds like a backfire from the exhaust (a popping noise). What could explain that?

I know you guys are way smarter than I am on these cars and I appreciate the help!!

SonicRaT

iTrader: (6)

Stock vert rims are 15's.

Backfires are common on rotarys, but could be a faulty ACV, no cats, various emissions peices not operating properly, etc.

Kevinsino

My bad,I thought the stock BBS's were 16".

The car is completely stock (besides the rims and a cone-shaped K&N air filter). It has 186,000 miles and is running great.

But thanks for the words SonicRaT.

trent1059

Not to hijack, but....are backfires common with everything operating properly?
Mine backfires all the time when I let off the gas to shift, do I need to worry or start looking for something wrong?

SonicRaT

iTrader: (6)

I usually don't come accross them on a 100% functional car, but they are rather common for cars that have some miles on them. If I ever get a car that does it and the owner wants to fix it, the stuff I usually do is.

Full tune-up (plugs/filters/plug wires/adjusting the TPS and checking it/cleaning BAC/etc)

If it's still there, I go through and check all of the emissions equipment (cat/acv/egr/everything), then I'll run some techron through for simplicity sakes or send the injecdtors out. About 90% of the time this seems to cure it.

SonicRaT

iTrader: (6)

Oh, you can calculate your speedometer reading on various websites, try this:

http://www.miata.net/garage/tirecalc.html

Stock tire was 205/55R15 for the verts if I remember properly. Check inside your door on the tag to verify.

trent1059

205/60/15 for the vert stock tires, I don't think the 55 vs 60 profile will affect the speedo......

1990RXHeaven

Alot of it depends, i think, on the type of exhaust sys. you're running. Have someone drive behind you when you do it, I you got some real hot **** comin out of your pipes, maybe you're thrwing some flames. Not necessarily good, but damn cool.

SpaYllwS2K

Hmmm How fast are you going when you "open it up on the road"??????? Huh????




Ohhhhhh I'm telling!!! You are busted Buddy! /LOL/

Isn't it fun having an upper hand on your older brother.. gosh this is fun

Tessai

^^ How nice, you named your s2k after me .

cmjaure

I think the stock size is around 25" high (dont have my tire book handy so numbers arnt 100%) just see if they are about the same height and it shouldnt make too much of a differnce and if it does it might not even be noticable

SpaYllwS2K

Well not specifically after you... just because. I always name my cars and well my S looked like a "Kyle" to me