Modification of the NA engine

llsaw

Known Member
Senior Member
Dec 23, 2003
195
1
3,018
Penang
thespfiles.blogspot.com
"If you're running 11.9 and engine is in "safe" condition meaning that your setup is "mild". Im running that compression wif avgas only, cause even V Power will knock like hell"

Oops.. this probably means that your mapping is incorrect with too much advance or your dynamic compression is too high from running too small a cam profile/ports or your combustion chamber profile is inefficient with too much hot spots. My setup is as "mild" as 11.9 compression, 292/288 cams and race ported cylinder head with 180+bhp will allow me. Also if you're running a 4G93P head and inlet manifold you might want to disable the EGR along with the EGR code on the ECU as this will cause pinging at light throttle/cruising loads due to dilution of the intake combustion mixture.
 

V8_nutter

500 RPM
Senior Member
Aug 5, 2004
516
2
3,018
llsaw said:
"If you're running 11.9 and engine is in "safe" condition meaning that your setup is "mild". Im running that compression wif avgas only, cause even V Power will knock like hell"

Oops.. this probably means that your mapping is incorrect with too much advance or your dynamic compression is too high from running too small a cam profile/ports or your combustion chamber profile is inefficient with too much hot spots. My setup is as "mild" as 11.9 compression, 292/288 cams and race ported cylinder head with 180+bhp will allow me. Also if you're running a 4G93P head and inlet manifold you might want to disable the EGR along with the EGR code on the ECU as this will cause pinging at light throttle/cruising loads due to dilution of the intake combustion mixture.
FYI my mapping is correct and im running high ignition with "maximum" advance possible (aka drag setup). Im not running 4g93p head and im not running that inlet as well, im on mivec head wif fabricated 4 throttle. No point you running 288/292 with mild ignition and safe mapping, dont make sense to me. Disable the EGR code ?? what wiring do you mention ? im not using stock wirings.
 
Last edited:

V8_nutter

500 RPM
Senior Member
Aug 5, 2004
516
2
3,018
llsaw said:
Unless your engine setup warrants it, running too high an octane fuel actually will at best result in no increase in power and at worse cause you to lose power. A fuel with a higher octane reading is often more difficult to combust efficiently.
Low octane might suits your engine though, it wont suits mine. From 4000 rpm onwards, it will knocks like hell, suitable for low cam but not for my high lift cam.
 

V8_nutter

500 RPM
Senior Member
Aug 5, 2004
516
2
3,018
You talking about hot spot, sometimes these things you can't avoid. What we can do is to minimize it, if your target is to win races you will tend to have a "lean" fuelling setup wif almost maximum ignition available, then to compensate this only race fuel can do.
 

chris2000

1,000 RPM
Senior Member
Apr 14, 2005
1,114
24
3,138
What V8_nutter is tuning the engine for maximum power with excessive advance ignition which will not be applicable for street use. Hence you will find 97 or even 100 octane fuel is low. Of course with high racing octane fuel you can run higher compression, more advance ignition and more boost if turbo. But it just not practical for a daily street driven car. Like a friend i know running 4G63 big turbine for daily use at 1bar on 92 octane pump gas. then on the dragstrip with a flick of a switch the whole fuel + ignition mapping change to 1.6 bar but this setup can only be use with full high octane drag fuel only!!

LLsaw's car is a Daily Driven putra running high static 11.9 compression with high overlap cams which reduces dynamic compression. He's car is properly tune and map for our regular 97 octane gas churning out all possible maximum power with his setup. So when a car can run properly with 97 octane does not mean it is not tune maximum!!!

So if it is a street daily driven car, and the car pink or knock, then it is definitely that the car is NOT TUNE properly to be daily driven for 97 octane! Just simple as that. Track and race car is total different ball game.

The Honda B18C-R engine, even stock is 11.0 compression, and I'm sure many members are running fine on regular 97 oct gas.

The MME race spec B18C-R engine are slightly higher at 11.2 to 11.5 comp, and it had no problem running on 97 oct for 12 hours non-stop race! The MSS race spec B18C-R engine are even higher at 12 to 12.5 comp with high overlap cams doing perfectly fine on 97 oct gas for short race!! It boils down how you tune and map your fuel + ignition on ECU for the 97 gas you using and the appropriate use of the car.
 

llsaw

Known Member
Senior Member
Dec 23, 2003
195
1
3,018
Penang
thespfiles.blogspot.com
Don't know what's a drag setup? Drag engines usually last 1-2 races before complete teardown and really not a good benchmark. Likewise the cooling of the engine is not up to it as the engine barely gets hot enough with heat soak in a 400m run. Static ignition should be left at 5 deg BTDC with dynamic advance depending on your engine setup and of course engine load. You control the dynamic advance via your ECU maps. On an engine with big profile cams giving a lot of overlap and with big ports bleeding off dynamic compression the static compression ratio should be increase else you will lose low end power.

Static compression ratio = measured compression when engine is not running
Dynamic compression = compression of the engine when the engine is running.

You can get by relatively high compression if you run big cams. That is the way to go. If you're pinging you're most likely running lean or you have inadequate cooling of the intake charge. Having an airbox with CAI setup or better still water injection into your inlet manifold will help in this aspect.
 

V8_nutter

500 RPM
Senior Member
Aug 5, 2004
516
2
3,018
llsaw said:
Don't know what's a drag setup? Drag engines usually last 1-2 races before complete teardown and really not a good benchmark. Likewise the cooling of the engine is not up to it as the engine barely gets hot enough with heat soak in a 400m run. Static ignition should be left at 5 deg BTDC with dynamic advance depending on your engine setup and of course engine load. You control the dynamic advance via your ECU maps. On an engine with big profile cams giving a lot of overlap and with big ports bleeding off dynamic compression the static compression ratio should be increase else you will lose low end power.

Static compression ratio = measured compression when engine is not running
Dynamic compression = compression of the engine when the engine is running.

You can get by relatively high compression if you run big cams. That is the way to go. If you're pinging you're most likely running lean or you have inadequate cooling of the intake charge. Having an airbox with CAI setup or better still water injection into your inlet manifold will help in this aspect.
Drag setup = maximum everything without thinking much of reliabity. We dont use big overlap cams for drag, we use high lift so that's the difference. FYI we running 4 throttle meaning that "airbox" is irrelevant.

llsaw,, running lean makes the "most" horsepower if you really want to know.
 

V8_nutter

500 RPM
Senior Member
Aug 5, 2004
516
2
3,018
chris2000 said:
What V8_nutter is tuning the engine for maximum power with excessive advance ignition which will not be applicable for street use. Hence you will find 97 or even 100 octane fuel is low. Of course with high racing octane fuel you can run higher compression, more advance ignition and more boost if turbo. But it just not practical for a daily street driven car. Like a friend i know running 4G63 big turbine for daily use at 1bar on 92 octane pump gas. then on the dragstrip with a flick of a switch the whole fuel + ignition mapping change to 1.6 bar but this setup can only be use with full high octane drag fuel only!!

LLsaw's car is a Daily Driven putra running high static 11.9 compression with high overlap cams which reduces dynamic compression. He's car is properly tune and map for our regular 97 octane gas churning out all possible maximum power with his setup. So when a car can run properly with 97 octane does not mean it is not tune maximum!!!

So if it is a street daily driven car, and the car pink or knock, then it is definitely that the car is NOT TUNE properly to be daily driven for 97 octane! Just simple as that. Track and race car is total different ball game.

The Honda B18C-R engine, even stock is 11.0 compression, and I'm sure many members are running fine on regular 97 oct gas.

The MME race spec B18C-R engine are slightly higher at 11.2 to 11.5 comp, and it had no problem running on 97 oct for 12 hours non-stop race! The MSS race spec B18C-R engine are even higher at 12 to 12.5 comp with high overlap cams doing perfectly fine on 97 oct gas for short race!! It boils down how you tune and map your fuel + ignition on ECU for the 97 gas you using and the appropriate use of the car.
Running 12.5 comp wif 97 octane ?? horsepower must be down, not maximum enough. Perhaps suitable for track race.
 

chris2000

1,000 RPM
Senior Member
Apr 14, 2005
1,114
24
3,138
""Drag setup = maximum everything without thinking much of reliabity. We dont use big overlap cams for drag, we use high lift so that's the difference. FYI we running 4 throttle meaning that "airbox" is irrelevant.

llsaw,, running lean makes the "most" horsepower if you really want to know.""


Running 4 throttle doesn't mean an airbox is irrelevant eventhough it is meant for racing only. Have you seen that many race cars in Europe that runs Individual Throttle Body (ITB) aka 4 throttle for 4-cylinder engine, many have custom airbox made out of fiberglass or carbon fiber with a hose ducting cold fresh air from the outside. This is because the cooler the air the More Hosepower and also to reduce intake temp which in turns reduce ping/knock in an engine.

And who doesn't know that running a car lean will give more horsepower. There is only that small limit and margin of error, before high horsepower with ZERO reliability happens. That is why there is so many JUNK yard shop to sell you engine kosong when blow engine or melt a piston!! And mind you, I think "DRAG Setup = maximum power without thinking reliability" is rubbish! Every Drag car want to achieve highest power but not wanting it to blow at the drag strip! Don't tell me you built drag engines without thinking reliability and expect that it will blow during drag race.


""Running 12.5 comp wif 97 octane ?? horsepower must be down, not maximum enough. Perhaps suitable for track race.""

Like I said earlier the car is tune for max horsepower for 97 octane gas. So how to say horsepower is down and not maximum. Official sanctioned circuit race in Malaysia only allows 97 octane like a normal road car. Hence car is tune to maximum for use with 97 octane.

Of course if we were running some 100 octane or F1 or A1 race fuel, the tuning of the engine will be different to maximise more horsepower from these type of racing fuel.

What I am just trying to point out is that, No Matter What type of Fuel you are using, you will still be able to tune for MAXimum Power without knocking and pinging if the tuner has done everything right.
 

llsaw

Known Member
Senior Member
Dec 23, 2003
195
1
3,018
Penang
thespfiles.blogspot.com
Yes but running too lean also raise the temp to beyond acceptable levels. It's all in the compromises.

High lift cams will also bleed off the dynamic compression. Most NA big cams are high lift and also high duration.

Prooperly implemented individual throttle bodies or as you call it 4 throttle or 6 throttle or 8-12 throttle depending on how many cylinders you have do utilize carefully ducted airboxes and piping. Just check on the BTCC engines from previous years (before the single TB regulation) or even any modern NA race engine. One good drag example would be the latest Skunk2 racecars but those are probably running close to or more than 16.0:1 compression. If yours is filterless or running on sock-type filters and sucking in the hot air.. Oh well.. looks fierce though ;)

So irregardless of what a one race 400 m drag setup you want to use which is probably out of scope for 99% of the ZTH forumners, the original point is that 97 octane is ok for a high compression engine if you map and setup your engine carefully. And yes.. a higher compression engine running on this petrol will make more power than one with lesser compression again provided the parameters and engine mapping is optimum. There are however limits to the compression you can run with 97 octane petrol before all this becomes a waste of exercise and this exact figure depends on which tuner you speak too as the engine combination and setups are frankly endless..
 
Last edited:

Random Post Every 5 Minutes

I decided to park my car on roadside at pj housing area main road, jln ss3/14, due to clutch pump leaked, only frm 7.15pm to 9pm, just now. I intended to force drive it on 2nd gear when traffic is clear at 9pm but when I arrived, found that driver's side door was unlocked, I was shocked that steering wasn't there, boot also left opened, my 2 spare tyre on rear seat also not in the same position as before, some wiring cut, i believe someone tried to start the engine but failed. It's just a...
Ask a question, start a discussion or post something for sale!
Post thread

Online now

Enjoying Zerotohundred?

Log-in for an ad-less experience