Right now in my Eg Hatch I installed an Ls/Vtec. The person I got it from who built it, said it's a stock bottom end (but refreshed), with an B16 head with ITR cams, and a Skunk2 IM. I am currently using a gsr tune, but don't know when to set the vtec engagement point.

I was going to try and tune it myself, but dont have any experience at all. I am afraid to mess with the timing and grenade my motor. I was going to get it tuned and then try to download the tune, and see the difference between the stock and modified tune.

My questions are what vtec point should I set my tune right now, and the second one is how to get started with tuning? Thanks in advance

 

My advise is if you have no experience do not touch the tune! you can screw something up, But also dodnt be afraid to start learning, You can play with vtec and you wont hurt the engine, But every engine will like a slight different vtec point and this is something the Tuner has to figure out for the best performance,

You can start with 4500 rpm low and 5500 rpm high cam and use between 30-60% minimal throttle % for vtec to engage, My tuner had mine set at 60% but I did not like how I had to push the pedal down so far down to get vtec engaged so I set it to 30% and I like it much better. My vtec is at 4700 low and 5000 high so just around 5k rpm it will engage and I like how that feels with the boost from my supercharger.

If you want a very good starting point contact http://www.phearable.net/ and they will set you up with a very good base map! Just tell them the mods and they setup a safe tuine to drive on, from there you can learn to adjust the fuel tables by street tuning it your self or find a tuner and have him fine tune the base map.

Watch Jeff Evans videos and subscribe he has very good tuning videos to learn from, here is a start,

 

i have my vtec set at low at 5700k and high at 6k on CTR cams And pulls hard. But what is the low and high used for? Is it for the ecu to read where to engage vtec within those rpm range you set at? I’ve never had it set lower but when I got my motor tuned he set it at 6k but we had problems with vtec engagement but now I got vtec to engage I just left it where it is.

i suppose when it was tuned that’s where the low cams fell off and where my high cams wants to engage at so he put it at 6k for vtec. Is that too high?

 

I cant say because every engine likes a different setting whether its boosted all motor ect. and especially what cams are used.

Vtec engagement is not solely based on rpm, its also based on load and TPS%. Depending on how much load and TPS% you have at a certain rpm will determine when or if it will activate. Most B series will redline around say 8,400 rpm, IMO vtec from 6k to 8,400 rpm is a bit short with a 2,400 rpm window power band for a N.A engine but again every engine is different and if the tuner felt you made better power with vtec set their then I wont argue cause im not a tuner.

Years ago when Hondata was starting to come out with the S100 i was still using a Apexi VAFC Vtec controler and i on my all motor GSR i would play with the settings and ended up with something very low like 4,200 rpm low and 4,700 rpm high driving around vtec engaged much faster with these settings and felt fun but i never did any real world testing on the dyno to ever know if i lost or gained power in the rpm band.

If you want to lower it go for it I don't think you will hurt anything, and if you don't like it just change it back or just click download and then upload in settings to bring back the original tune on the ECU.

check the TPS minimal % for vtec and see what its set too and lower it no more than 30%

You can try 4,500/ 5500 rpm and see how you like that. With 30% in any gear it shouldn't be hard at all to engage vtec soon as you get past 4500 rpm!

 

Yea I read that a lot of boosted setup lower their vtec around the 4K range and yea I don’t like the short vtec range either, my tuner raised my redline to 8900k and I didn’t like that much as I didn’t care for much to rev to the moon I just want power in the mid to high range.


If I do lower vtec that means I would have redo my fuel percentage on vtec?

also what does the low/high on vtec Settings mean in Hondata?

 

the VTEC-window says, when VTEC can be activated or not.

example:
lower boundary: 4500rpm and 787mbar
upper boundary: 6000rpm and 653mbar
Minimum Throttle: 50% throttle
Minimum Speed: 15 kph
Minimum Temperature: 65°C

This means, that your VTEC can be engaged at 4500rpm, medium load (column 6, here) when you hit 50% of throttle, but if you don't hit 50% throttle and that load, your VTEC WON'T be engaged untill you are at 6000revs.
upper 6000rpm your VTEC will be engaged if you want or not.

this helps to earn more milage, for example or gain power, if possible and neccessary.

you can lower the vtec engagement point 500-600 rpms without any tuning on a stock setup with basic bolt-ons, you can lower it more with tuning and additional aftermarket parts (straight pipe etc). You can get more gains with some leaning out of the air-fuel mixture but you need to do some tuning to know for sure and to do it safely. Any basic vtec controller like mentioned above will work, I've ran one long ago and I really liked it. Hondata S300 is obviously better, I also prefer a smooth vtec engagement point at lower rpms rather than a harsh one at higher rpms, it helps with handling in long sweeping curves, and in wet weather conditions, smooth is better IMOVTEC

VTEC is one mechanism Honda uses to achieve good emissions, fuel economy and engine power from a small displacement engine. The function of VTEC (variable valve timing and lift electronic control) is to provide two distinct camshaft profiles which are switched electro-hydraulically. The smaller camshaft profile is called the low-speed cam; the larger the high speed cam. The camshaft profiles are switched depending on engine rpm and load, usually from 2500 rpm to 6500 rpm. The main effect on tuning of VTEC is that there are usually two copies of every major table - one for the low speed camshaft, one for the high speed camshaft.



Warning
• Do not set the VTEC point too low as the engine will lose oil pressure and possibly damage the engine. It is not recommended to set the VTEC point below 2000 rpm. • Do not set the VTEC point too high as the high speed cam rocker arm may float on the lost motion assembly, damaging the valve spring retainers. It is not recommended to set the VTEC point over 6500 rpm.

VTEC Point

The determine the best VTEC point perform two dyno runs, one with VTEC set low (e.g. 3000 rpm) and the other run with VTEC set high (e.g. 6500 rpm). Set the VTEC point to the intersection of the high speed cam and the low speed cam. Generally if there is a sudden increase in engine output immediately after the cams switch then lower VTEC. Conversely if there is a sudden dip in engine output then raise the VTEC point. Since the VTEC point will be at the intersection of the low speed and high speed cam torque curves, it is normal for the torque to dip slightly around the VTEC point.



Generally the VTEC point will be 5500-5700 rpm on a stock engine, 4500-4800 rpm with intake & exhaust, 3000-3200 rpm for supercharged applications. Aftermarket cams generally require a high VTEC point.



VTEC Window

The VTEC window uses a combination of rpm and manifold pressure to determine when to switch cams. This is so that the cams will not switch at light or medium throttle - which is undesirable for fuel economy or driveability reasons. See VTEC parameters for more information on the settings.







Setting the VTEC window
1. Determine the optimum VTEC point by performing a dyno run on the low speed cam and then the high speed cam. 2. Set the VTEC rpm window lower rpm to the VTEC point value. 3. Set the VTEC rpm window higher rpm to 6000 - 6500 rpm. 4. Set the VTEC window pressure to 80 kPa up to the lower rpm value. For forced induction set the pressure to 110-120 kPa. 5. Set the VTEC window pressure to 40 kPa at the higher rpm value. 6. Smooth the pressure transition between the high and low point. The pressure values are interpolated between rpm points, so it is not necessary to have multiple rpm points between the high and low rpm window values.

Forced Induction
1. As above, but set the lower pressure values to 120-150 kPa at the lower rpm value, decreasing to 70-80 kPa at the higher rpm value.

Normally there will be a small dip (less than 5 lbs torque) at VTEC. If there is a greater dip, try changing the VTEC point up, in 100 rpm increments, to see if the dip is reduced.



As see VTEC crossover tuning