I’m currently running high compression on my 1.7. Does anybody know or recommend if I should be using a colder sparkplug? I’m currently running CTR pistons with a 2 layer spoon gasket. I am consedering using a 1 step colder plug but I can’t find anybody who makes them for the 1.7 motor. Can I use plugs that are designed for a b18c? Will the plugs for a b18c sit to deep into the chamber and cause contact.
1.7NA
sorry, i don’t have an answer… but i have a question about your setup.
I’m just wondering how the car runs with compression that high. The compression ratio calculator says that the CTR pistons in a b17a yeild 11.3:1 compression… plus your headgasket. I’m not sure how much that bumps it, but probably up to around 11.5 or 11.7
Does the engine run good off of the 91 octane we get here in cali? or do you have to add octane booster? What is your timing set at? And do you know if you can pass smog with the compression that high?
any input would be greatly appreciated, cause i’m currently trying to decide on pistons for my b17a. thanks!
91IntegGS
I’m in the california too so my car see 91 octane all the time (I don’t use any octane booster) Car does seem to ping sometimes slightly at lower rpms with a load (like going up a hill and doing a upshift from 1 to 2) otherwise the car runs fine. My timing is at 14. I also run a skunk2 ecu so the car tends to run on the rich side, which probably helps. I haven’t had a chance to install my fields controller yet. I’m sure with a little tuning, the slight pinging can be eliminated. I don’t think smog is a problem since I was able to pass without a problem when I had just had the pistons with the factory headgasket. Smog time is coming up really soon, I’ll keep you posted and let you know that goes.
HTH
good luck!!
1.7NA
CTR pistons
CTR cams
ITR mainfold
I/H/E
I’m assuming you have a GSR… or did you swap a b17a into your RS/LS/GS (I’ve got to swap one into my 91 GS… which may be difficult to get the BAR sticker on).
so you only have a little pinging now. How about when you had the stock head gasket? did it ping at all then?
also, how does your setup feel? its going to be very similar to mine. I’m rebuilding the b17a w/ high comression, and eventually getting some cams, the bolt ons, itr intake manifold… I’m pretty sure i’ll be happy w/ the power output, i just want to be sure.
Sorry for barging in on your post again, hopefully you don’t mind. Its just its rare when i find a cali person trying to pass smog legally, and rarer when they are running really high compression. I’d really appreciate any updates you have when you do finally to to the smog station! Thanks.
Run a NGK BCPR7ES-11 or NGK BCPR7E-11 Spark plug. They run about $2.50 per plug and need to be replaced at 15,000 mile intervals. Best of luck.
91IntegGS
More than happy to share with everybody here. Car was running fine with 11.3 but I didn’t realize that the timing was set to about 18-20 so it pinged a little. Once I had it at 16, it was fine. This was on a stock ecu. Yes, I have a 93 GSR so your setup will be very similar to mines. (YS1 tranny) Car pulls strong from 3.5k to redline (8.5K). My last dyno with stock cams were 173hp and 122ft lbs to the wheel. I haven’t got a chance to redyno the car since the cam swap, .3-.4 higher compression. Once I get my fields controller installed, I will redyno and hopefully, I will be at the 180whp mark. I’m pretty sure you will be happy with this type of setup. It will also depend on the cams you run. The CTR cams give alot of midrange power and good top end power compare to the stock cams.
HTH
G2guru,
Thanks for the info. Would you recommend going with a step colder plug? Since my car is not tuned yet, I want to make sure that the slight pinging doesn’t hurt anything. Also, would you recommend a FPR at this stage of my setup? I’m running the stock injectors but my fuel regulator has been “crushed” to up the pressure a little.
thanks
1.7NA
thanks very much! I think now i might just have to go for the CTR pistons, but i may just stick w/ the p30 to be 100% sure.
thanks again!