Budget turbo tips

[binarypunk]

Unless you are using a regulated power supply then a 7805 voltage regulator will pop before long. They're just not suited to the nasty electrical environment in automotive applications....jump starts, booster packs, aged alternator rectifiers, dumbasses connecting the battery up wrong, and all sorts of other things, will produce transients and reverse voltages that will overwhelm its protection. An LM2937 would be a much better choice, being designed for automotive environments...so they include protection for reversed polarity (up to 50V) and against the kind of spikes (150V+) that you get from booster packs being connected and such forth. This is not to mention that a 7805's operating temp range is pathetic...the 2937 is rated for -40C/+125C and so can cope with the sorts of temperatures found under bonnets and deep midwinter and such like. Plus its RF protection is vastly superior.

However, a 'Radio Shack'/Maplin employee when asked for such a thing will have the same look on their face as a McDonalds employee when asked for a terrine of foie gras, so you would need to go to a proper distributor to find one (and the capacitors it needs) - or if you pop £3 in my paypal I can furnish you with a set. It works in the exact same way (is in the same package too, so it is a straight swap).

Mind you it's hardly a critical application, so it doesn't matter much if it breaks, but still....

[Lazza]

I used to have an O2 clamp on mine when it was running a JR Powercard and later an eManage blue piggy-back ecu. My understanding of what it does is a little different to yours though.
It does intercept the O2 signal into the ecu but the reason for it is because below 4k rpm the stock ecu tries to run from the sensors and only runs from built-in maps over 4k and at WOT. That means that with a piggy back ecu, if you try to change the fuelling below 4k rpm the ecu will detect the change and fight to bring the AFR back to what it thinks it should be. The O2 clamp I had was set to give 0.5v which according to the ecu was stoich which meant I could do what I liked with the fuelling without the ecu trying to "correct" anything.

[nedski]

I used to have an O2 clamp on mine when it was running a JR Powercard and later an eManage blue piggy-back ecu. My understanding of what it does is a little different to yours though.
It does intercept the O2 signal into the ecu but the reason for it is because below 4k rpm the stock ecu tries to run from the sensors and only runs from built-in maps over 4k and at WOT. That means that with a piggy back ecu, if you try to change the fuelling below 4k rpm the ecu will detect the change and fight to bring the AFR back to what it thinks it should be. The O2 clamp I had was set to give 0.5v which according to the ecu was stoich which meant I could do what I liked with the fuelling without the ecu trying to "correct" anything.

Yep your right and a correct and better explanation than mine.
I explained it that way because mine cut's in on boost only and I've set it to give a lean signal 0.35v. It helps with my flat spot best when set this way.

[BenF]

That's a good shout on the diesel intercooler - they take more pressure. I should think an M-B sprinter 320 CDi unit would be a good upgrade from there when you're ready?

[nedski]

Ran Both days at the Blyton bash and the Turbo stopped on and tight. Ran without a manifold to turbo gasket and so far spot on, no problems. Just a smear of very high temp copper sealant. I hope this is the cure for me.

[Mazda Mender]

We were dealing with a few problems with the turbos over the two days.
M-m

[nedski]

If anyone fancies doing a budget build without a PNP ECU this is my rolling road print out from Blyton. Being paranoid about running weak at high revs and also having very little control over anything, this shows at 10-11psi how rich i'm going over 5000 revs and how quickly this makes the power drop off.
My brothers normally aspirated 1.8 mk1 also went on the dyno and had a great long flat usable 114 hp at the wheels.
Anyway here is the pic.

[nedski]

Thought i'd just add to this post.
After a successful year with my basic fuelling and timing mods, I have now succumbed to the megasquirt and all the problems that it brings. Although in the end it's worth it.

So this is not a fitment guide but just a comparison of dyno graphs with and without megasquirt. Nothing extra has been done to the engine.

Please note my graph that's already posted is at the wheels. These new graph's are adjusted to approx flywheel figures.

torque figure with megasquirt


Bhp figure with Megasquirt


For doing nothing but adding a proper ECU the power gains are quite substantial.

So it can be done either way, but in the end the extra control of an ECU when Budget's allow is a must.

[nedski]

We were dealing with a few problems with the turbos over the two days.
M-m

A year on at Blyton and nothing changed. Sympathies Carl