First attempts at mapping a VVT engine without VVT...and mapping with megasquirt...
 

Good morning everyone!

After reading around, it's clear this is the best place to get involved with and seek advise and suggestions.

The sitrep is as follows:

I have a '99 NB RS Import, with a '53 1.8VVT engine installed after the older non-vvt 1.8 let go.

VVT is currently disabled/retarded and will stay as such for the foreseeable future (one day, i'll be buying VVTune, or a later megasquirt ECU)

Engine is largely stock, with the following modifications/changes:

• 250cc injectors from the MK2 engine (as opposed to the 265cc injectors that came with my new engine, if these are better, i'll fit em...)
• VICS manifold albeit with VICS currently disabled
• Running the original MK2 "return" fuel rail
• PLX Wideband & ebay sourced IAT sensor
• ICV blanked off (don't ask)
• VVT in full retard

I'm running a custom-build Megasquirt 2e running 3.3.3.

Through a bit of trial-and-error, as well as having a look at a few publicly available maps, i've cobbled something together which runs pretty nicely, returns fairly decent economy, and has lots of power over 4K. I don't believe it's detonating, knocking or pinking, but i'm fairly new to this and haven't developed the ability to hear that on the road. The map extents beyond 100kpa as the maps i worked from had a wide range of aspiration systems. I am currently running naturally aspirated (although i intend to fit a TD04L in the coming months).

Finally, she's running exclusively on 99ron or better fuel.

Your thoughts and comments on the attached tables would be highly appreciated!

Tim

First off, welcome.

I'd start by enabling/wiring VICs and VVT, nothings going to be ideal until especially the VVT is properly working.

Also, all NBs have returnless fuel rails. Big difference.

And I was going to suggest sending the 265 injectors out for servicing since you've got a spare set, but if you're going turbo soon, I wouldn't bother.

I'd find a dyno to fine tune the fuel and spark maps.

Looking at the tables, there's two major issues:

1. You're only using 50% of your vertical resolution due to the cells above 100kpa. Use "table generator" to generate a reasonable table. I'm guessing it'll also fix problem #2.

2. I'd say full throttle AFRs are around ~.5 too lean. I prefer low 13s, I think even mid 12s. I'd have to look at my last few N/A tunes, but definitely not high 13s.

3. Spark map is going to be about 6-8 degrees from mbt, I've found almost all BP N/A tunes make the most power around 28*. I'd knock your spark down to 30-32 if you're confident in the AFRs and initial timing, see what that does for you. Don't grenade another motor though.

Hola and cheers for the welcome!

1. Yeah i had intended to sort that now that i've figured out that around 170kpa would cover my theoretical boost from the TD04. Am i best starting with a VE map that only covers NA usage?

2/3. Duly noted, will have a little play and advise

From what i'd read, all USDM NBs have returnless fuel rails? Mine is a JDM import (and i'm in the UK). The fuel rail 100% has hose line at each end so i'd be shocked if that were still a returnless line!

*EDIT* How does the attached screengrab look for a VE generation?

VICS is going to be overlooked most likely as i have a squaretop which i'm cleaning up to fit, which is why i was also debating the 265cc nozzles. They've got less miles on them, and whilst i AM going turbo, it'll be running wastegate pressure for probably quite a few months until i sort clutch and various other components out.

Sadly my MS2e won't run VVT, so i was planning on "making do" for the time being, knowing i'll be loosing 10-20 lb/ft at the bottom end of the range.