355z28

iTrader: (8)

Alright so i pulled the car out again the other day and was under the hood and at about 1/8 throttle the engine starts shaking then clears up with a little more throttle, then in another spot starts doing it again and so on. Its not really a miss. Basically it acts like its detonating really bad, almost like there is to much timing in it.

When i had pcmforless do my tune i had them do it for a 160 stat. I ended up misplacing my hypertech thermostat, which is still missing so i put back in my 195 OEM thermostat.

Now i know with the engine running cooler you can run more timing, with being tuned for a 160 and running a 195 cause this problem???

sorry for the story, just trying to get as much info out on it as i can.

Formula350

iTrader: (3)

180 is OEM, just for the record. If you got a 195, then oops

1994Z28Lt1

iTrader: (1)

wow 11.4:1 compression and you have a tune for 160 degree stat but you're running a 180

the higher compression will really make your engine a lot more sensitive to temp and timing changes i would say you problem could have something to do with too warm of a stat being in there

not only that but you said you just pulled the car out, do you mean after the winter? if you did try some fresh fuel and see if that helps at all

but overall i would say im pretty certain the reason they have the option for what stat your running is not only to know what to set the fans to come on at but also to adjust the timing accordingly

355z28

iTrader: (8)

Ive had it out this year, its just been raining a lot here so i havent driven it much lately. Ill have to get another 160, hopefully it will fix most of it.

C_Rules

iTrader: (7)

just an FYI with 11.4:1 compression i would say definitely get yourself datamaster and tuner cats. you will need to log the car and monitor it to make sure you are not getting any knock. mail order tunes are good but when you bump up the CR like that it's important to make sure you're not getting retard. i used to get a bunch of knock and not even feel it. found out about it when i got datamaster.

i'm just curious do you know what your dynamic compressions ratio is? i just learned a little about it myself. and was curious to what yours may be.

355z28

iTrader: (8)

no clue what it would be, where can a get data master??

C_Rules

iTrader: (7)

i hope your car likes 93 octane. some cars can go 11.4 on 93 with no detonation and some can't. it depends on your DCR.

if im not mistaken datamaster doesn't work for ob2 cars so you will have to look for another logger. or switch to an obd1 style port.

355z28

iTrader: (8)

how is dynamic CR figured?

caldercay

BTW - dont buy another Hypertech. It's really a MotoRad thermostat that
the Hpertech folks stick in their box. Seriously, I ordered one and when it
came out of the box, it had MotoRad stamped on it. MotoRad offers 180*
and 160* thermostats in their standard version and the Fail Safe versions:

http://www.motoradusa.com/catalog.php

Save some bucks and get the MotoRad. Available at Auto Value Parts Store,
Autozone, Canadian Tire, Fisher Auto Parts Stores, O'Reilly, and Parts Source.

moehorsepower

iTrader: (3)

You basically went up a point in compression, NO your engine will not shake even under detonation, You have a miss.If it was truly detonating you would hear it rattle like marbles in a blender and usually you will not get detonation in a no load condition, Running a 160 vs 180 thermostat has nothing to do with it, Factory settings with 180 stat is around 220 degrees! If you want prove it to yourself then drain your fuel and add 5 gallons of 104 race fuel, if it is so called detonation (which it is not) it will stop, It probably is your Opti..

355z28

iTrader: (8)

Why would you say its my opti?? just asking not disagreeing.

infinitebird

iTrader: (11)

If your timing was advanced much for a 160 optimized tune then you probably don't want to go backward to the 180. It probably will not hurt you but you might get some knock retard if you have too much timing in it. If the timing was not changed much or at all then it doesn't matter.

Formula350

iTrader: (3)

Could be old plugs if it's pinging... Sad thing about LTx problems, is everyone jumps to Opti Even then, it might just be cap and rotor and not the Opti itself.

355z28

iTrader: (8)

plugs are delco platinums with about 2,000 miles on them, and the msd unit has around 1200. I dont know what all bryan did with the timing, i might give him a call after bit. Since im running so rich anyways he said he would retune it for shipping, so id like to stick a data logger on it and e-mail the results to bryan to get it as close as possible.

i have a friend that owns a mechanic shop that has a datalogger from mac tools, it records a lot of stuff and can be transfered to a desktop, i think ill give that a shot...

C_Rules

iTrader: (7)

what makes them fail safe? i wouldn't mind spending a few bucks to get me a fail safe 160 over my current 160.

355z28

iTrader: (8)

the failsafe is just a stat that when it fails it only sticks open so it will not overheat.

Formula350

iTrader: (3)

Yep, they're spiffy, like Z said, they stick open.

355z28

iTrader: (8)

and i would like to know where to buy this motorad thermstat, i went up the street to Auto value, theirs is a special order part #307-60 and their parts master #30760, then i drove up to Oreillys theirs is also a special order part# 4216 brand it murray, then last i went to carquest which carried stant, theres was also special order i didnt get a part number.

Formula350

iTrader: (3)

I'm pretty sure Stant would have a 160 for ours. I like Stant.

C_Rules

iTrader: (7)

looks like i'll be getting one of these. whats a few buck to potentially save a head gasket or ring.