----

VEMS dev info

We are currently running 1.0.73 and have tested the function of the engine and the dyno. We now wish to try 1.1.x firmware, most recent version as simple trigger is now supported.

The one feature we would like to see is a table for injection end angle in 1.1.x. Is that feature far away?

Some people don't care, and point to the fact that engines that need it are race engines. I'm not going to change their minds but I don't consider an engine that sputters unburnt fuel out the exhaust very sophisticated. This function does offer substantial gains in idle and low load tunability on similar engines, being able to map the end point with load and rpm is important for many engines, this is one of them and I know many other engines that would benefit from it.

We have tried rotating the injector table and one of the positions seems to pull slightly more vacuum at idle and make it appear just a tiny bit more controlled, it's hard to tell from the lambda what is happening here but we only have 180 crank-degree coarseness in the changes and from what I hear the injection begins when the primary trigger is activated, on this engine about 50 degrees before TDC. $FlgChr1$FlgChr> There is a lot of pulsing in the intake runners, idle can be greatly affected depending on how the engine came to rest at idle. Worth noting is that it is difficult to get a solid idle at leaner than lambda 0.90, as on many other similar engines.

Related web pages

* PortInjected/SequentialInjection

* GenBoard/UnderDevelopment/FirmWare (wishlist needs an update)

----

[Project forum thread]

Basic mechanical specifications:

* Volvo B23 block

* 2.7 litres with 96.75 mm bore, stroker crank

* Forged pistons, 12.4:1 c/r

* 530 head, aggressive cam (stock lifters just wide enough)

* Exhaust: Timo racing extractor manifold

* Intake: Flared runners, large plenum, 80 mm BMW V8 throttlebody, adjustable runner length (35 cm to 45 cm)

Electrical specification

* Bosch wasted spark coilpack

* Simple crank trigger using GT1 Hall sensor, two teeth on front pulley

* Secondary trigger, one tooth on balance shaft

* Siemens/Deka 630 cc/min high-Z injectors (using gasoline)

Engine characteristics

Current dyno results show about 25-27 kg of torque @ 5400 rpm, and possibly 230-240 crank hp around that point. Max reliable rpm with the stroker crank is 6500-7000 rpm, but not much to gain above 6500 rpm anyway.

With the current cam we have about 90 kPa at 1000 rpm idle. With 1500 rpm idle we get 70 kPa, it's not too bad. It's hard to get it running solid at leaner than lambda 0.90.