Spark plug for BOT: heatrange change and copper/iridium

e-jump

Known Member
Senior Member
Mar 13, 2004
203
8
3,018
Petaling Jaya
Visit site
Hi folks.
Tried to do some digging (till 2009 dated threads), and did not find any dedicated thread on sparkplug.

I have a boosted D16 with 'T28 .49AR hotside' and stock internals (exception to ACL duraglides and cometic 1.5 gasket) doing 0.5bar.
Been running fine for months (i did an engine swap months ago, but the BOT+tune was carried fwd from my previous engine also D16 running BOT for 1.5yrs) and it was tuned on BKR6E and gapped at 0.30".

I did some searching on homemeadeturbo and dseries sites, most of them recommends the 7 heatrange and copper. For some odd reason, i cant find the BKR7 anywhere here =__=.
I checked out some other BOT ppl do here on other engine, and they are using Iridiums.

As im thinking for my next tune to go 0.7bar, i really need to consider heatrange change.
Should I be ok with Iridiums, or i better off order some BKR7E from ebay(transportation fee will make it expensive and make the price close to iridiums bought locally)?

Currently on full boost+WOT my oil temp gets to 105C and water gets to ~98C.
Maybe on current setup/tune, just changing the heatrange may drop my temp?

Rgds
 

vr2turbo

Beyond 20,000 RPM!
Helmet Clan
Moderator
May 11, 2010
29,998
8,385
1,713
Petaling Jaya
As far as I know, cooler heat range plugs just helps removing heat from the combustion camber, so as not to overheat the plugs. When they becomes too hot it will cause pre-ignition. Unless you have gained 75 to 100bhp change, then use a colder plug by one number. If not, just use the same heat range. My 200bhp 4G63T uses number 6 only.
Friend told me if want to find copper number 7 plugs can try motor cycle shop, as bikes uses colder plugs, but make sure same size, especially the length.
Platinum and Iridium material are higher heat resistance only. I don't think you will get additional power but they do last longer as they are tougher so wear resistance. Copper electrode will get rounded off. Platinum and Iridium tips are hard and very fine (small) so they hardly wear.
 

e-jump

Known Member
Senior Member
Thread starter
Mar 13, 2004
203
8
3,018
Petaling Jaya
Visit site
thanks for the response.
currently my D16 is at 179whp (stock n/a should be around 110).. so i would expect that by going to 0.7bar, i will be around 200whp mark.
with the exception of FPR still stock, i do have the support mods of 510cc&walbro255 running emanage blue.

when tuning for max power back then, engine managed to do 181whp but theres ripples at top end (which i think the limit where knocking starts to happen).
then settled with slight pulled timing.
So i would expect going from here onwards, heatrange7 would help me.
For now BKR6E's and ZFR6's do the trick, but i need to start scouting for the copper 7.
I think i tried motorbike shope once, but seems they have champions (maybe i should try more other bike shops).
I did came across some posting on Copper vs Iridiums, and copper seems to be best for heat..something something due to its tip and being the best conductor especially when working with smaller gaps for fine spark(?).

But i guess iridium 7s should do the trick fine, and a better option than staying copper 6's, yes?
 

Veloc

3,000 RPM
Senior Member
May 19, 2010
3,234
991
1,713
Sabah
Finally... It has been some time since someone come up with such interesting discussion.

How about heatrange 7? Usually, going colder by one heatrange is okay even for stock. But strictly just one. Just be bold especially in our kind of weather. If you are still doubtful, NGK actually produced a "6.5" range for those who wants to go a bit colder but do not dare go a whole range colder. Same for Denso. The have heat range 21 (NGK6.5) in between 20 (NGK 6) and 22 (NGK 7). Then upgrade a bit of cooling. Oil temp at 105 is around the limit. Water as well!!!

Anyways, why not use iridium with heat range 7? Is there a strong reason for copper? Not sure about peninsular, but for my place here in Sabah, all the dealers and sellers only stock up variable heat range for iridiums. With standard plugs, they only have the stock heat range. I am currently using Denso Iridium Power and very satisfied since the first day till now. Avoid OWS at all costs. I think I did started a tread last time regarding my experience on OWS crappy plugs.
 

e-jump

Known Member
Senior Member
Thread starter
Mar 13, 2004
203
8
3,018
Petaling Jaya
Visit site
strange thing is that for some odd reason, BKR7s is not popular at all in (at least)Selangor.
Even Sunway doesnt have em, of all places.
wwhhhhhhyyyyyyyyyyy (ノ ゜Д゜)ノ ==== ┻━━┻
*and i never seen the 6.5/21 range before. Bike specific plugs?
**my engine only takes BKR/ZFR and not the BCPR and others

When i did some research on BOT, i always come across usa sites and the BKR7E is the popular plug for BOT on honda, miata and old school audi/bimmers (and maybe more).
While most post talks about copper plug gets the job done with fraction of money and dont waste moneys on Iridiums, some post did talk about the superiority of copper plug spark at smaller gaps against the iridiums, at the expense it doesnt last as long.
So till date, i still stay with copper 6s (because my car was tuned with it anyway).

But when i came across few BOT projects here, i see some just use the Iridiums IK's.
So i was wondering, should i just go for the iridiums 7s n call it a day, or ebay for the copper 7s and follow the sure ok tips on those honda forums.
*i will still need to check the plug gap once in a while anyway regardless of what plug i ended up with.

how i wish someone were to do a bulk order/buy for the BKR7s, count me in i'll be happy to take few sets and keep in vacuum bag for future replacements.

for the time being, maybe i should try the iridiums and see how my temp goes w/ the same current tune.
 

Veloc

3,000 RPM
Senior Member
May 19, 2010
3,234
991
1,713
Sabah
My car's manufacturer recommended plugs are BKR6xx. They have the equivalent model in iridium which is BKR6IX or something. Used it and no problem. It's just the material they use to construct the plugs. measurements and protrusion are all the same. You can even choose which preset gap you want when buying because gapping iridiums are tricky and not recommended. So if it's just the material difference but get the job done, i do not see why you stress over copper or iridium. I suppose not for cost savings? Yes iridiums are more expensive but they pay off in the longer run. And from what I see you do not have a lot of choices now. If it were me, i'd just get iridiums to save the headaches since all aspects are the same if you follow the plug code. It's just the material.
 

vr2turbo

Beyond 20,000 RPM!
Helmet Clan
Moderator
May 11, 2010
29,998
8,385
1,713
Petaling Jaya
Yup, probably they stock Iridium 22 because copper 7 not available. I tried looking for 7 before, but finally ended up with a set of IK22. Less than a year blew one set and got that replaced. Less than another year that did not run well too, so I went back to copper, but my VR club mechanic switched them to platinum. I did not continue with iridium because it just cost too much RM160 against 30 copper. Now on Platinum because they cost slightly more around 50.
As mentioned, mine is 200bhp and manufacturer recommendation is 6 only, so I stick to that because easy to find and cheaper....hahaha
 

e-jump

Known Member
Senior Member
Thread starter
Mar 13, 2004
203
8
3,018
Petaling Jaya
Visit site
^
come to think of it, on my journey to search for bkr7-copper i also did not come across platinum 7s.
only the IX.
For your case you are in best of luck because the 6's range is plentiful, even the copper 6 is easily obtainable. But why you dont go for copper? just going platinum for peace of mind lasting longer?

For me the plug gap is not a concern because i got the gap-adjustment tool. So i can just grab bkr6es-11 on the shelf and regap it .
maybe its a better idea for me to search for/try platinum 7s before taking the plunge for 7ix.
 
Last edited:

vr2turbo

Beyond 20,000 RPM!
Helmet Clan
Moderator
May 11, 2010
29,998
8,385
1,713
Petaling Jaya
Yup, I have not seen platinum 7 also, so your best bet will be the expensive Denso Iridium.....:biggrin:
 

Random Post Every 5 Minutes

Hi Guys I Need A 40dcnf Weber ...
Anyone Have ..pls Call Me
Gobbi 012-9163905
Urgent Buyer

Thanksss
Ask a question, start a discussion or post something for sale!
Post thread

Online now

Enjoying Zerotohundred?

Log-in for an ad-less experience