Saabscene Saab Forum - Saab Technical Information Resource banner
1 - 7 of 7 Posts

·
Registered
Joined
·
47 Posts
Discussion Starter · #1 ·
I've just fitted some NGK BCPR8ES plugs to my 9000 Aero, Which I purchased from Elkparts.
Only problem Is the engine check light came on after a short test drive.

These are advertised for highly tuned trionic applications, my car has an Abbott ECU upgrade.
Is there a way to sort this or should I put the stardard plugs (NGK BCPR7ES's) back In?
 

·
Registered
Joined
·
1,448 Posts
The CEL is probably due to mis-fire from excessively cold plugs. I'd say use standard ones until 300+ hp is reached.

But others may have different oppinions. Might be something else.

Dubbya~
 

·
Registered
Joined
·
2,928 Posts
Gary, you need to decode the "check engine" warning to find the problem. See this explanation.

I don't regard a standard Aero with just a brain upgrade as a highly tuned trionic application, so I'd stick to the standard plugs (can't remember what they are). Others may disagree, but I think our friends with 350 bhp Aeros run standard plugs.

One will be along shortly to comment.
 

·
Registered
Joined
·
14,305 Posts
The cold plugs shouldn't generate a CEL. They do the same job electrically as the warmer ones. I use the BCPR8ES on my 9k (not quite 350hp yet)without any probs. You need to diagnose the cause of the CEL.
[edit] This assumes the plugs have been properly gapped to 1.1mm. If they haven't, then this might cause a CEL.

The plug heat range is affects how well the plug conducts combustion heat to the head- a "colder" plug conducts it better and is less likely to suffer pre-ignition problems. However if combusiton temps don't get high enough it will get fouled.
 

·
Registered
Joined
·
47 Posts
Discussion Starter · #5 ·
Thanks for your help on this guys
, the fault code was the lamda sensor.
I've put the standard plugs back in and got the lamda sesor reset, thanks to Two stroke to turbo for sorting that out this morning.
They thought the lamda sensor might be playing up so I'll see how It goes.

I think I'd better ask first before I change anything else!
 

·
Registered
Joined
·
323 Posts
Originally posted by Bubbles:
[qb] suffer pre-ignition problems. [/qb][/b]
What would be the symptoms of this?
I am guesstimating that on my set up I am just above 300bhp and currently using BCPR7ES. I don't appear to have any performance issues but would it be an advantage to switch to the cooler plug?
 

·
Registered
Joined
·
1,448 Posts
I think most highly modified street cars will not "need" a higher heat range plug. Here are the two reasons I think so:

1. You spend most of your time cruising at part-throttle, and because many highly modified cars have much better exhaust scavenging they often have cooler combustion temps when cruising. You can foul up plugs in a highly modified car if you spend most of your time cruising on the highway, or on short trips around town.

2. a) Higher than average combustion temps caused by increased power will be shorter in duration because if you have *twice* the horsepower you can only accellerate for *half* the period of time without going well over the speed limit. The stock plugs should have enough thermal inertia to absorb the difference in street use.

B) Generally speaking, when upgrading a turbocharged engine, the peak combustion temperature doesn't go up much, nor the peak pressure. If either goes up significantly, it will be pressure, rather than temperature.


I'd reserve the BCPR8ES plugs for track use, where your average combustion temps are really likely to soar. They're an easy part to change ... and it couldn't hurt to have a set of them around in case you go to a track day. But why waste money on them for a street car if it doesn't need them?

Of course, after saying all that, it doesn't matter which of those two plugs you use as long as they aren't a) fouling, or B) causing pre-ignition.


For learning more about plugs: http://www.centuryperformance.com/spark.asp

For figuring out quickly how yours are running (too hot? too cold?): http://www.spark-plugs.co.uk/pages/technical/diagnosis.htm

Dubbya~
 
1 - 7 of 7 Posts
Top