Any pics of teh set up for throttle/brake??


BACK TO THE THREAD TOPIC:

Here's some info for anyone that’s like me and want to learn more about how VTEC work.

Traditional VTEC system (B18’s with VTEC), each cylinder has 3 intake valves and 3 cam lobes: two (normal/small cam lobes) that are for normal driving (0-4500 RPM) and one (power/large cam lobe) for more aggressive driving (4500-redline) When the engine reaches above 4500 RPM, a pin is hydraulically pushed to lock ALL cam lobes together. Therefore, only the LARGE cam lobe is used, which means more power.

Here’s a video that explains everything PERFECTLY:

http://www.honda-marine.com/video/VTEC.wmv


In the L15A VTEC system, it uses 2 valves for exhaust at all times and it alternates between one and two valves for the intake side. For the L15A VTEC engine, at normal driving, the engine uses one intake valve. When more power is needed, the second valve operates to increase the amount of airflow into each cylinder since valve opening times are shorted with RPM increases. (That sounds really confusing even to me )

Here’s a link where you can learn about the different models of the 1.2l, 1.3l and 1.5l, all SOHC i-DSI designs (twin spark) and finally a 1.5l SOHC VTEC version which is not i-DSI.

The Truly Amazing Honda Fit/Jazz


Hopefully this helps!!



PS: if I’m wrong, by all means, correct me. I want to make sure that everyone gets the right info including me.

 

your right except theres only 2 Intake Valves, its still a 16valve, 2 Exhaust 2 Intake, but there is 3 lobes, the pin locks the lifters together and both intake lifters ride the large cam lobe.

 

sorry, my bad. Got a little too eager. (think faster than i type)

 

in most cars it's only 2 lobes, hence 2 stage vtec

iirc only one car used a 3 stage vtec and it was in a D series

 

D-Series was the only to uses 3 Stage Vtec(JDM D15B), yes, but all the Vtec motors have 3 lobes per cam per cylinder either intake, exhaust or both.

There is 1 low cam lobe for each valve, 2 intake valves 2 intake lobes, then when you add Vtec to the equasion you add 1 Vtec(high cam) lobe, so you have 3 lobes per cylinder(intake) and 3 lobes per cylinder (exhaust) if its DOHC Vtec 6 lobes total per cylinder. When Vtec engages, it locks both intake lobes together with the Vtec rocker, so insted of 2 independant rockers, you have 1 that operates both intake valves.

If its SOHC Vtec theres 5 lobes per cylinder, 2 Intake Low, 1 Intake High, and 2 Exhaust, SOHC Vtec only operates Intake. DOHC does both.

The 3 Stage Vtec on the D15B operates Vtec High cam on the Intake only(just like sohc vtec), but it added a 12 to 16 valve switch similar to the Fit Vtec.

Vtec-E on the 92-95 VX and 96-98 HX's is similar to SOHC Vtec, but insted of operating the Intake valves on vtec at high rpm's it did it at low to help with fuel economy.

 

Can device such GREDDY e-manage or Apexi altered the Vtec engagement(changeover) point? My L15A vtec changeover point at RPM5000.

 

To me the answer is .......

The exhaust dumps from the head to the fire wall on the Fit and on the other (radiator side) on Civic etc.

Further proof is the quite a bit different sound of the GE because of the cast in head exhaust manifold.