Safe A/F ratios for a RB?

[Imation]

I wanted to comfirm what a safe A/F ratio is on a rb?

Currently running gt2860R-7 running 17psi, stock cams, and 15-16 degrees of timming in higher load areas.

WOT seeing 12.8 from 2200-3300 aprox.
working down to 11.6 from 3600-7k rpm +- 0.2.
Idle is 14.9
Cruising or light load 13.8-14.2

All this was measured by the aem uego lambda ratio.


Lastly any thought on meth injection when adding more boost/timing?


Thanks
Dan

[falcon]

Your AFR's are just fine.

Is this on a base map? Or was it already tuned?


I can't comment on timing but I wouldn't worrya bout the AFR's

[NismoS-tune]

Mid 11s to 12s are great at WOT if you don't mind gas milage. Running rich never hurts your engine, just your plugs lol

[Imation]

Alright so i guess the rb is the same as most engines with mid to late 11's to mid 12's for a/f.
Any thoughts on meth injection for running higher boost or running more timming. Anyone here run meth?

[christdeyoung]

Mid 11s to 12s are great at WOT if you don't mind gas milage. Running rich never hurts your engine, just your plugs lol

Running an engine too rich can wash down the cylinder walls, so thats not good.
You usually don't have to worry about that until your AFR goes <10 or so.

[Velders]

I have no personal experience with meth, but I hear its a great investment.

[JD74]

Any thoughts on meth injection for running higher boost or running more timming. Anyone here run meth?

I personally wouldn't touch it for a Turbo car, as it's just another headache in terms of maintenance/tuning etc....and something else to go wrong.

The only time I have used it was in a Centrifugal SuperCharger application where an Intercooler was not an option (and Centrifugal SuperChargers don't respond well to inline intercoolers, at all, in most cases) as a BOOST COOLER after the SC, injected pre-intake manifold/plenum.

We (Skyline Owners) have the ability to mount HUGE Intercoolers (with NO moving parts, fluids etc!), so there is really no good reason for meth, especially for a street driven car. Cryo Kit your Intercooler if you are THAT concerned.

Many Tuners will tell you the same thing, as long as you remember to say STREET CAR

[NismoS-tune]

On the contrary, many tuners encourage meth on turbo cars. Lots of skylines,, srt4, mspeed3, cobalt ss, supras, turbo g35/350z, hondas and so on have used water/meth with turbos and not laggier like a bigger 4" intercooler. I'm sure lightspeed, Z-tune, AFI and subracing could agree.

I personally wouldn't touch it for a Turbo car, as it's just another headache in terms of maintenance/tuning etc....and something else to go wrong.

The only time I have used it was in a Centrifugal SuperCharger application where an Intercooler was not an option (and Centrifugal SuperChargers don't respond well to inline intercoolers, at all, in most cases) as a BOOST COOLER after the SC, injected pre-intake manifold/plenum.

We (Skyline Owners) have the ability to mount HUGE Intercoolers (with NO moving parts, fluids etc!), so there is really no good reason for meth, especially for a street driven car. Cryo Kit your Intercooler if you are THAT concerned.

Many Tuners will tell you the same thing, as long as you remember to say STREET CAR

[Skym]

Safe is 11.6:1 A/F ratio.

14.7:1 A/F ratio is ok for stock engine at idle.

As engine transistions from vacuum to boost (0+ on boost gauge), you want the A/F ratio plot to head towards 11.6:1 (more air from turbo = more fuel) at peak boost at lower rpms and be at 11.6:1 right until peak power. Most widebands should have software that can datalog A/F ratio vs rpm.

Ignition timing needs to be done on a dyno to see the affects on Power, Torque curves. And need headphones to listen for knock if you push ignition timing too far.

[JD74]

On the contrary, many tuners encourage meth on turbo cars. Lots of skylines,, srt4, mspeed3, cobalt ss, supras, turbo g35/350z, hondas and so on have used water/meth with turbos and not laggier like a bigger 4" intercooler. I'm sure lightspeed, Z-tune, AFI and subracing could agree.

Be my guest Professor......throw it on your car.

Why don't we just make all Tuner's lives easier and run nothing but C16....... gimme a break.

Why would anyone with a half a brain wanna run Meth on the street ?

[falcon]

Be my guest Professor......throw it on your car.

Why don't we just make all Tuner's lives easier and run nothing but C16....... gimme a break.

Why would anyone with a half a brain wanna run Meth on the street ?

Many people do... a few skylines here and pretty much EVERY RX7 out there running over 15PSI.

[NismoS-tune]

http://www.skylinesaustralia.com/forums/Water-methanol-Injection-t281683.html&hl=water+meth

http://www.riceracing.com.au/water-injection.htm

[Velders]

I may not have any experience with water/meth, but they do, and seem to like it:

http://www.modified.com/tech/modp-09...kit/apexi.html

[GTR-Dad]

Watch your EGTs to evaluate whether your AFR is rich enough. 950 C is a temperature you don't want to exceed. Add fuel to bring EGT down.

If you want to advance timing, get on a dyno and listen for knock. Stop adding timing when you reach mean best torque or the knock threshold. With the boost you're running, you'll probably encounter knock before mean best torque, so back it off a few degrees to guard against detonation from bad gas, higher temps than you tuned at etc. Advancing timing will also reduce EGT, so you may be able to pull a bit of fuel when your timing is set.

However, a smart tuner once told me he'd rather leave a bit of extra fuel there to protect the engine.

Remember flame speed is higher at higher cylinder pressures so you'll need to pull timing before you turn up the boost.

I've cleaned up this thread as the OT wanking is an embarassment to GTRC. Smarten up.

Dan

[tokes]

I personally wouldn't touch it for a Turbo car, as it's just another headache in terms of maintenance/tuning etc....and something else to go wrong.

The only time I have used it was in a Centrifugal SuperCharger application where an Intercooler was not an option (and Centrifugal SuperChargers don't respond well to inline intercoolers, at all, in most cases) as a BOOST COOLER after the SC, injected pre-intake manifold/plenum.

We (Skyline Owners) have the ability to mount HUGE Intercoolers (with NO moving parts, fluids etc!), so there is really no good reason for meth, especially for a street driven car. Cryo Kit your Intercooler if you are THAT concerned.

Many Tuners will tell you the same thing, as long as you remember to say STREET CAR

Dare I ask why centrifugal blowers won't work well with intercoolers? All those Procharger and Paxton Novi cars running around must be doing something wrong. The only kits that come with air/water coolers are the Vortech kits, but there's a lot of aftermarket air/air upgrades for them.

A meth injection kit is a great way to increase the amount of boost/timing/compression and therefore power you can run on pump gas. I've heard of some 4G63's making over 700 AWHP on 93 octane + meth, you wouldn't touch that on straight pump gas. Look on evolutionm.net, and see how many cars there are making ridiculous pump gas power with meth injection.