Performance upgrades

[viper cape]

Earlier this year a customer brought his sx in for water hose replacement. He also complained that he had fitted a cheap turbo and needed more power but turbo was at its boost limit.
We fitted a mild set of regrind cams and degreed correctly.
Car now pulls much stronger from 3000 rpm, has much more power, after retune lighter on fuel and we could run at a boost level safe enough for cheap turbo to survive.

[viper cape]

A client with a ca18det bought a turbo off a 16v golf . After he fitted this turbo he was very unhappy with spoolup. We found that a smaller exhaust wheel trim with same exhaust a/r size made the turbo work better for his application.
Choose wisely and note that turbos do not spool the same on all engines of the same cc .
exhaust manifold diameter, pipe length, cam timing etc all make a difference.

[viper cape]

Toyota 4age twincam 16v turbo pushed 165kw at 1.1 bar boost on std internals.
Port cyl head ,oversize valves from camry fitted into head and 258 cams. Car now did 213 kw at the wheels at same boost levels.

[viper cape]

Remember porting only helps midrange if you do not over port cyl head.maintain good air speed in port and you will have a fairly efficient engine.bigger ports need to run richer for similar low down to midrange performance.

[BigKriss]

Toyota 4age twincam 16v turbo pushed 165kw at 1.1 bar boost on std internals.
Port cyl head ,oversize valves from camry fitted into head and 258 cams. Car now did 213 kw at the wheels at same boost levels.

Interesting. I have built , mmm, probably 30 odd Alfa Romeo 2.0/4 and from 2.5 to 3.7 V6 turbos.
I found that the smaller valves on the v6 2.5 12v heads worked wonders for low end torque but did restrict power from 6500 rpm upward. Never really liked revving the little Alfa engine beyond that anyway. I must also say that the power levels we talking about here are 240 wheel hp at 0.7 bar pressure. Std internals etc.
Fot the more robust power levels I needed the std 30l sized valves But ONLY on the intakes !

Now on the multi valve head the small 2.5 sized valves worked brilliantly due to there being two of each per cylinder. This I found for the n/a engine as well, even when the capacity was taken out to 3.6 l. Again power levels were in the 280 wheel hp range at 0.7 bar pressure. For the monster output engines, std. sized 30l valves sufficed. Oversized intakes worked very high up in the rev range with the big engines....

http://www.youtube.com/watch?v=Q-Y6qnPQO_8


Nice power from your little engine though..!

[viper cape]

On the twincam engine we found if we over cam the turbo engine it makes power to high up in the rev range and most customers cannot afford to build one to hold together at that point. The big valve gives us a broader power band.
I am trying to give the guys an overview as to how changes affect different engines.

Good to have you back.
At the coast we tend to make good power but connot get any timing out of it and need to run fuel mix.

[BigKriss]

When you say your`e not getting timing out of it, explain please..?

[viper cape]

If we tune a car at the coast and settle at 15 deg timing for max tractive effort for example, in Gauteng we can hit 28 to 30 deg on same car. I can lean out to approx 12 a/f and get more timing but tune might be borderline.