Question-Port and Polish

[Vhtfhwlego]

I knew u would say that.

Whole of this week, I had been asked by those evil friends of mine everyday to jio others out.

When you be free as everyone is in town.

[Cerano]

had done a 2.4 CRV with head porting, bore throttle body, intake manifold, n exhaust. re-tuned & gain 7whp.

 

no bad fc after that. all hand job, no machine involve.

 

many ws can do it. pnp alone shd cost around 1.5k. down time bout a week +. best is ws hv spare head

 

u intend to stroke it n pnp or jus pnp? if jus pnp, better upgrade ur cams

 

wah bro mod so much only 7whp diff?

[Mini-itx]

wah bro mod so much only 7whp diff?

 

Well, he already mentioned its hand job, not machine job.

 

However, head porting alone is not going to give you much gains. Sometimes, its even negative gain....

 

IF you have bigger ports to flow more air, your cams and valves must match it as well, else it will become a bottleneck and makes porting useless.

 

http://www.billzilla.org/engcombust.htm

 

Chck out this great website about 4AGE head. See the port angles. If engine head is not designed for performance, porting will hardly improve anything.

 

[Accordboy]

IMO,7whp gain for NA engine is gd..kinda hard to extract hp from na engines...

 

[Mini-itx]

IMO,7whp gain for NA engine is gd..kinda hard to extract hp from na engines...

 

Agreed. Its hard to extract power form NA engines.

 

Even stroking up an engine yields little power increase as well. Eg. going from 2L to 2.2L yields just around 20-30HP for NA. Very little compared to FI engines.

 

Going higher RPM is the only way to gain alot more HP but you need to do lots of work to get there (head word, lighter internals, stronger valve springs, cams etc....) Then you can maybe extract 280-300HP from a 2L engine (provided you redline it at 10K RPM).

 

But then at such RPM you will have to rebuild engine very often.....

[Djdp]

Well, he already mentioned its hand job, not machine job.

 

However, head porting alone is not going to give you much gains. Sometimes, its even negative gain....

 

IF you have bigger ports to flow more air, your cams and valves must match it as well, else it will become a bottleneck and makes porting useless.

 

http://www.billzilla.org/engcombust.htm

 

Chck out this great website about 4AGE head. See the port angles. If engine head is not designed for performance, porting will hardly improve anything.

 

 

second that, in the case that i mentioned, totally stock engine.

[Djdp]

IMO,7whp gain for NA engine is gd..kinda hard to extract hp from na engines...

 

 

agreed. tc much easier.

 

either that, u can also pay higher price for a ported head from USA.

 

But again, it depend on what other mod u intend to do.

 

Easiest way, drop a k24, or supercharge it.

 

[Cerano]

because a simple tune would usually yield around 5bhp for NA alr taking into account 20% transmission loss you still get 4whp

 

and porting + boring of tb should yield quite abit

[Cerano]

agreed. tc much easier.

 

either that, u can also pay higher price for a ported head from USA.

 

But again, it depend on what other mod u intend to do.

 

Easiest way, drop a k24, or supercharge it.

 

supercharging is too complicated.

 

installing a roots blower or a twinscrew would cost too much

 

turbo is easier + better to mod

[Hermitage]

Well, he already mentioned its hand job, not machine job.

 

However, head porting alone is not going to give you much gains. Sometimes, its even negative gain....

 

IF you have bigger ports to flow more air, your cams and valves must match it as well, else it will become a bottleneck and makes porting useless.

 

http://www.billzilla.org/engcombust.htm

 

Chck out this great website about 4AGE head. See the port angles. If engine head is not designed for performance, porting will hardly improve anything.

 

HeeHee! Sounds kinda wrong "hand job"!

 

Anyway, thanks for the link! I'm running a 4AGE 20V Blacktop which probably needs overhaulin' soon. Plan to do it at the end of this year. Wonder if I should change the head to a Silvertop one since the website recommended a closed head with "squishing" areas...

[Mini-itx]

supercharging is too complicated.

 

installing a roots blower or a twinscrew would cost too much

 

turbo is easier + better to mod

 

Actually roots Supercharger can be easily to customised one and CHEAP!! Don't need oil and water lines.

 

Just get used Eaton superchargers from ebay and you can fabricate some pipes and brackets and feed air into the manifold. Because of low boost, don't even need intercooler. Many chargers comes integrated with a bypass valve so don't need BOV. Some even come with a electromagnetic clutch and you can on it only when necessary.

 

And roots charger is instant power right at the foot. No lag at all.

 

I almost do up a custom M90 charger for my M42 motor till I sold the car and have to scrap the idea.

[Cerano]

Actually roots Supercharger can be easily to customised one and CHEAP!! Don't need oil and water lines.

 

Just get used Eaton superchargers from ebay and you can fabricate some pipes and brackets and feed air into the manifold. Because of low boost, don't even need intercooler. Many chargers comes integrated with a bypass valve so don't need BOV. Some even come with a electromagnetic clutch and you can on it only when necessary.

 

And roots charger is instant power right at the foot. No lag at all.

 

I almost do up a custom M90 charger for my M42 motor till I sold the car and have to scrap the idea.

 

cheap? the pulleys cost a bomb already leh.

 

okay la used then worth it.

 

but low boost?

[Lammy84]

Actually im of the impression that stroker kits are mainly for gains in torque rather than BHP, do pardon me if im wrong :P

Its gonna be extremely costly (not even mentioning drivability yet) for a 2L engine to hit 300bhp, even if u dump in a k24 its for torque gains mostly.

Imagine the torque of a 250-300bhp TC engine minus all the lag. Yummy!

[Djdp]

because a simple tune would usually yield around 5bhp for NA alr taking into account 20% transmission loss you still get 4whp

 

and porting + boring of tb should yield quite abit

 

The CRV is awd. Loss is even higher.

 

Another point to note is that car is stock so not looking at fig only.

Overall performance n drivability is achieve through the process

 

Sc is bolt on for certain make

[Thedream]

wah bro mod so much only 7whp diff?

 

I agree... 7whp most butt dyno also cannot tell the difference...

[Galantspeedz]

I knew u would say that.

Whole of this week, I had been asked by those evil friends of mine everyday to jio others out.

When you be free as everyone is in town.

 

All your evil frens ask you jio others out? For what sia? I sure last car de......

You must have done something to your car recently and now find people to tear like tissue paper right?

[Vhtfhwlego]

The last thing I did was to wash my car.

That was during F1 weekend.

Maybe smoother surface and they wanna see before and after lor.

But anyway, your Euro R is a dream car for mr personally as got the exclusive drive.

[Djdp]

I agree... 7whp most butt dyno also cannot tell the difference...

 

mayb diff butt

 

anyway the car is already tuned b4 pnp & it's now over 200hp