yanik

Hi,
I took Pauls spark map from https://www.miataturbo.net/forum/t18648/
and I got serious knock from 156 kpa boost (156 kpa value from spark map). I've retarded Pauls map and additionaly set MS to retard timing by knock signal from KnockSenseMS. It's better but there is still knock by 180 kpa (I hear a ping so it's not a false signal from KnockSense) - by pinging spark is retarded even to 4....is it safe to retard more???

Any ideas what to do?
retard more?
tune fuel? (AFR's seem ok to me),
get a thicker head gasket? (maybe my head surface is too much cut during rebuild and the engine has to high compression? )
maybe 130 F intake temp is to high?

It's a 94 miata on stock head gasket, on 98octane gasoline, have forged 9:1 wiseco pistons from flyinmiata and their stiffer springs and 1mm oversize valves. the engine is barely broken-in (1200 miles)

Savington

iTrader: (31)

I have a few comments, and a few questions.

Comments:
-You're a DUMBFUCK for putting Paul's spark map on your car. That thread should be hidden from view until you have a thousand posts; putting a highly aggressive map on your car like that without any dyno tuning at all is so incredibly stupid.
-You need to figure out what your compression is. If you shaved the head, all bets are off; you need to have the motor CCed to figure out what YOUR compression ratio is.
-Your AFRs look fine. A little shaky, maybe a few tenths lean above 4k, but not terrible.
-130 degree intake temps are unacceptable. Do you even have an intercooler?

Questions:
-Tell me more about the motor. 9:1 Weiscos and 1mm valves is all good and dandy, but what about headwork? What manifold/turbo/downpipe/exhaust are you using? Have you done rods?
-The spool looks terrible. Is this like a GT30R or some enormous turbo, or do you have wastegate issues?

Laur3ns

Yanik stop driving full throttle until you understand that you are killing your engine.

richyvrlimited

iTrader: (1)

I don't think 37DegC is too bad for intake temps, it could be fer better granted, but it could also be a lot worse. There's no way he's not running an IC (Water/Air?)

Agreed on the timing map though. That said, on admittedly pretty poor fuel octane wise, my mates highly modded Greddy runs about 12degrees btdc, with no knock. his intake temps are far lower than yours though.

Laur3ns

37 is OK, but you fail math class:
130 Fahrenheit = 54,4 C

paul

iTrader: (21)

Savington is right. My spark map isn't meant for Polacks without supervision. ie Artie

yanik

Thanks for Your answers,

Savington, didn’t know that pauls map is aggressive. I had the car tuned by a professional and the spark map was advanced to 40-42 by 75-50 kPa without knock…the tunning has been done on a previous blow off that had a serious boost leak. I’ve installed Tial blow-off and got much more boost… that’s why I took a more retarded Pauls map - it's only 32 advanced in boost so it's less agressive then my previous....

From my calculations with my overbore pistons, even with 2mm (!!) shorter head my car cc is 1840... but You’re right I’ll measure the compression

I will work on it, for now ignition is the priority

mistake – I don’t know where I got this 130F from – its 115F max in the boost. Air filter is isolated from engine bay and gets air through a hole in firewall....Maybe I should get my oil cooler from the front of IC to the steering rack as FM does..…

All the head and block work has been done by best professionals, and it was full option for improved head flow, don’t know exactly was has been done but if You think it's crucial I could ask my mechanic for details
My miata has been professionally turboed in 1995 by a german tunning company HGP-turbo for 240 HP, so it’s their manifold/turbo/downpipe/exhaust. The car was running perfectly on HGP-modified ECU. I’ve melted a piston due to injector failure (I didn’t have EGT or AFR) After rebuild I ordered bigger injectors and the old ECU runned far to rich so I changed to MS PNP
the rebuild is done basing on flyinmiata parts: wiseco pistons, carillo rods, FM oversize valves, FM spring upgrade, RC 440 injectors, Megasquirt pnp, KnockSenseMS, GM EBC selenoid, AFR: Innovate Lc-1, SPA-design dual EGT/boost.


My turbo is poor old Garrett T25, it spooled a lot faster on the old ECU, I thought that it's a matter of spark tunning...
what do You mean by wastegate issues?

I'm carefull, I’m just trying to get rid of pinging…few pings should not destroy my engine..

hustler

iTrader: (6)

use this map, there is ZERO detonation in my motor.

hustler

iTrader: (6)

Decking a head doesn't make the cylinders larger or stroke longer, lol. WTF does 40* advance at 75kpa have to do with anything? Get control of your ****..."a little detonation" will kill a motor. Considering you have a few pulls with lots of detonation according the log, you need to park it and get a clue. BTW, this is coming from a German.

y8s

iTrader: (8)

uhh 2mm deck? I think you may have raised the compression from 9:1 to 11:1. good work.

yanik

Is it a joke? it's more advanced than Pauls map....

You’re right it doesn’t change the block height. Even if I have bigger pistons it doesn’t change anything - their compression ratio is given for their bigger diameter so that’s my second mistake

I'm sure that they haven't cut 2mm - I just got this 2mm from my wrong calculations.

Let’s forget my wrong calculations, is there any possibility of measuring compression ratio? Maybe I can calculate it somehow from cylinder compression?

any other ideas what could cause the pinging?

Braineack

iTrader: (62)

CR = 1 + cylinder vol/clearance vol

richyvrlimited

iTrader: (1)

didn't do any math, that's what the log said at peak boost on a particular pull

Savington

iTrader: (31)

That's how you measure it. Turn each cylinder to TDC, remove the spark plug, and use a pipe burette to dispense oil into the cylinder until you reach the top of the spark plug hole. Measure the depth of the spark plug hole. Subtract the volume of the spark plug threads from the total number of CCs dispensed and that's the volume of your combustion chamber. (this is called "CCing a head")

The compression ratio is the ratio of the swept volume of the cylinder plus the combustion chamber volume, to the combustion chamber volume.