I bought one of those o2 sensor air/fuel kits from jaycar. www.jaycar.com.au.
It appears to be calibrated to a certain type of o2 sensor, as I get very different behaviour between a CA18 and SR20 o2 sensor.
I haven't connected mine since, and I'd like to be able to calibrate it with an mechanic's accurate one to figure out whether
it's telling the truth.

Chris.

I have an idea in reference to turbo, A-14/A-15's.
The '79 thru '82 Datsun 210's (B310 or Sunny)in North America(& possibly elsewhere), were all emmissions spec with recessed combustion chambers & EGR. (Exhaust Gas Recirculation), built
into the cylinder heads. They had A12A's & A14's & A15's. All of these type of heads that I've seen would be useless for non turbo performance use, because of their low compression ratio.
They do however have the larger valves & oval ports just like a 'GX' cylinder head. Their pistons also have a recessed dish on top. Stock with no mods their compression might be a little
high for turbo use. But if one was to open up the combustion chambers in the head ,(there appears to be lots of material to grind away), one might be able to get a decent comression ratio
& flow for turbo use without having to use special pistons.(The EGR ports could simply be blocked off). If I can borrow a scanner,I'll try to post pictures of the head that I have.

The first motor that I turbocharged was a 1968 Datsun 2000 Roadster. It had 13:1 compression and it was limited to 7 pounds boost. That made a lot of Horsepower and held together real
well. I had the 1965 Pontiac GTO and the 2000 would run with it off the line and on top end over 150 MPH. Lower compression is used to get a more boost but is sluggish. Higher compression
gives great lows but the boost is limited to staying low. Total power is about the same. Give me the higher compression and lower boost any time.

When I put the 3" in my car, I bought a few pieces of mandrel bent 90 degree, 45 degree, and 180 degree angles and some long straight pipes and welded sections together and built the exhaust
system piece by piece by stacking one onto the other. It was less than a third of the price of a shop doing it. I used the 1 3/4" piping from the stock A14 exhaust manifold to the turbo and
the 3" from the turbo to the rear. From the rear axle back, I Y'ed it off into duals. It looked cool with the dual 3" exhaust out the back and sounded like an Indy car. It made everyone turn
their heads and look to se where the strange noise was coming from. I didn't use a muffler at all, the turbo quietened it down enough to keep the police off of me. I have pictures of it
someplace but I do not know which box of pictures they are in. I will post them when I find them. I have hundreds of thousand of photos that I have taken over the years of the whole world so
finding them will take time. I am sorting and scanning my photos all of the time and putting them onto CD's. I have been an avid photographer since I was a kid, sometimes doing 30 rolls of
film a day during a race, musical, or other event.
Back pressure is only needed if the cam warrants it. A good high RPM cam does not need any back pressure at all. Back pressure is for street torque at low RPMs.

James,

Sounds like fun! It should be one quick 1000 when your finished! A good clutch is a must. I have a stock one in at the moment and it slips bigtime. Took it for a long drive today and it just
slips 5500rpm plus. The 5 speed is going well at the moment, when i find a toyota box i will sell u this one but i need other things first.

If your going to go for forged pistons are u going to bore it out pretty big aswell? I would be for sure. If your going to use the stock cam and an A15 crank, it will be pretty tourqey 2000+
i would think?

Fester, you can only get 3" in mandrel bends. 2.5" is the biggest u can press bend. About the cost im not 100% on the difference. If i were to do James exhaust in 3" i would think it would
cost roughly $1000+. In 2.5" mandrel, around the $800 mark and press 2.5" around $600. This is still just a guess cause i dont quote. I guess 3" has the most potential for max hp as it flows
best but is it worth the $$? Thanks Mareo for clearing that up about the back pressure! Its all clear and makes sense now! cyas

Scott
Davo

>What sort of HP are u chasing? Are u going to go >the whole hog on the head and block or are u >going to use a rebuilt A14 or 15? Gotta >go.....cya

I'm not sure how much power i'll get, I just want the coupe to be pretty quick, however I don't want to have a sluggish low compression motor. So not less than 8.5:1 compression,
and around 7-11psi boost.
I'm tossing up whether I can afford forged pistons or not, they may save me money in the long run. On the head, I'll get some minor porting, maybe bigger valves if I can afford it.
And heavier than standard valve springs too. Electronic ignition is a must, standard cam, lightened flywheel and a good clutch. I want to use an A15, more displacement the better I
reckon.

Still want to sell me that 5 speed Davo? :)

James.

The more backpressure that the turbo has, the less rpm's the turbo will turn. Back pressure is for non turboed motors, with the turbo, you want no backpressure. For street
driving, the 2.5 exhaust should be fine but If I was going to be in full competition, I would want the 3" pipes on the turbo.

I was in agreeance with you on the 2.5" but more from the point of view of cost verses gain. Then again I guess that means I mean teh cost would not net the gain. I'm like you I'm unsure but
you are right why don't the drag cars just have a large dump pipe to just get the exhaust away from the body. Mind you there is a Kiwi turbo Toyota Starlet in the latest Fast Fours and it
has a dump pipe straight out the side of the front spoiler. I guess when you read all the talk about bigger is better it most often in context of late model high horsepower cars.
I just thought maybe 3" normal pipe may be cheaper than 2.5" mandrel bent and would give similar overall flow depending on the number of crushed bends in the system. I have never had a
mandrel system made up you may be able to set me straight on the cost issue.
Gavin

James, Andrew ran a few low 14 sec passes at a steet drag strip. If i took it to Eastern Creek with it all setup 100% with no problems, i think high
13's are within reach.

What sort of HP are u chasing? Are u going to go the whole hog on the head and block or are u going to use a rebuilt A14 or 15? Gotta go.....cya

Scott
Davo

It still depends on how much HP the engine is making and the size of the turbo. If i had an A15 turbo producing say, 150hp, 2.5" mandrel would flow the hp easy. 3" would flow the HP just as
easy therefore no real point. But if i had an A15 turbo producing 300hp (dreaming) a 2.5" system just couldnt cope. But, if i had a 3L V6 Turbo that only produced 150hp, a 2.5" would be
fine. 3" is only really nessesary in big HP engines so that it can flow the HP. When we did Croydon Autosports Civic drag car, its engines has over 1000hp and 4" pipe was needed to flow the
HP.

Then again, if i had an A15 turbo with 160hp and no dumppipe, just straight from the turbo, would the engine run more efficient than with a 2.5" system? I dont really know. I've never really
looked into it before. I supose your right because no pipe could flow alot of HP! Im assuming turbos need a little bit of back pressure tho. I mean, if Croydon Auto wanted the best out of
there drag car, would they have had no pipes right? Im stumped. Theres probably alot of room for discusion on this subject cause im not 100% sure. Im pretty sure 3" is just way too big for
an A15 turbo tho.

Scott
Davo