Q on SC with D16Z6 engine

[JZA]

First of all, just want to say hi to everyone. i m a newbie here.

I am wondering if SC the D16Z6 engine with 9PSI, should the V-Tec be disable? Please educate me .

[PWMAN]

No way! Keep the VTEC. Only drag racers disable it because of the tremendous boost they are running and the fact that VTEC creates a lot of valve overlap. But it's only necessary to disable VTEC when you are running 25+ PSI.

[JZA]

But, this car has stock internals. On a SOHC engine, will it handle? I don't want any damage on this motor since it is relatively low milage and very good condition.

[PWMAN]

Well 9 PSI is getting up there. The rods are the weak link in a D series. I'd say you can run 7 PSI no problem, many people have done it and it comes standard in a lot of turbo kits including Greddy. But SC give less stress on the engine, so if the kit is intercooled than 9 is OK, if not than limit yourself to 6-7 and definitely run premium gas either way. What SC are you using anyway?

[JZA]

The car is newly purchased. It has a JRSC with 9PSI pully. I don't feel the torque when I test drove the car and he told me that he disable the V-Tec. So, .. I am wondering what's going on. The engine is nice and clean and runs good. But, I want to get to know more about SC on a V-Tec. I am totally new to SC.

[PWMAN]

arghhh
JRSC suck balls, probably only gave the car a 40 HP gain, even with the VTEC so now that it is disabled it barely gives any.
He's probably lying about the 9 PSI pulley, does the car have a boost gauge? Ask him why it was disabled. When it is enabled you get an extra kick when VTEC kicks in because it's making more power.
What year/make is this car? I'm assuming it's a civic. And how much do they want for it? Personally I would look elsewhere for a car, JRSC's are not worth it. Find a good turbo car, or atleast one with a centrifical supercharger-they are much better. BTW the JRSC doesn't give all the low end power like they claim. I went to their website, looked at a dyno and it was only making a 10 HP gain by 3K RPM, and only gained 10 HP per thousand RPM after that, so really it gave a 45 HP increase. This dyno was for a 95 Civic EX.

[JZA]

it is on a 94 Civic Si. It has a boost guage. And, it does go to 9PSI.

He said that his friend did a dyno on another 94 Si (with JRSC) and that's the setting his friend has.

I will take the car to tuning/dyno again. But, I want to make sure that if the car equip with SC, when should the V-Tec kicks in and when to stop? I'd assume that a stock internal wouldn't handle 9PSI with V-Tec. But, I maybe wrong. That's why I am asking.

Thanks for your reply.

[PWMAN]

Having VTEC has no effect on how much boost an engine can handle. VTEC should kick in around 5K RPM, it's different for every model so I'm not sure about this one.

[JZA]

But, how ppl. manage to boost on V-Tec engine in general? 9PSI with V-Tec on @ 7k rpm is ok and safe?

[PWMAN]

People boost to 9K RPM with a B18C1. That engine is much stronger than a D16Z6 however. Boosting on a VTEC is actually safer. VTEC creates a lot of valve overlap which bleeds off boost. Having no VTEC severly hurts the top end performance.

[JZA]

Actually, I feel no torque when it doesn't have V-tec on.

Does anyone knows where to get more info. on this setup? D16Z6 engine with JR supercharger? I am sure that many ppl. have done this before. But, I have no luck to find good article about this.

[PWMAN]

That engine has no torque anyway, it's just a 1.6L!
Honda engines almost never have torque, they are infamous for HP, but low torque. Almost all their engine you have to rev really high to get power out of. Peak torque on that engine is probably like 5K RPM or something like that.

[JZA]

Exactly.