porting

[Benzo4gT]

If it makes so little difference what were you smoking to do 30-40 of them? :blink:

The port on the manifold was not just hacking out the opening to suit the gasket, 250g of material came out of the runners and reshaping the approach to the collector.

Attention was also paid to carefully porting in the right areas of the turbo volute while matching the gasket perfectly. It was altered post turbine as well.

The difference between the original collector opening and the ported one is a touch over 3.6cm^2 of area. I have not measured the volume increase in runners or the collector merge.

Porting is as much art as it is science, and when I see a dead stock 4g63 with a 16g go from 0psi un-ported to 4psi at 1750 rpm in 4th after porting not to mention the difference in mid range pull, I'll consider the possibility that proper

porting does next to nothing.

 

[White Knight]

I'd go with Leon on this.
Had exhaust manifold gasket leak number 1 cylinder boust came on later and would only make 16lbs.
Changed gasket back to 19lbs and boust all good.
It sounded like a supercharge whistle when pushed.

Fair enough, however...... I am not claiming additional boost nor do i make any claims on additional HP either. The "claim" I make is purely in regards to lowered threshold of lag and the lack of lack from prior porting to post porting.
I checked for leaks prior to the porting and had a small leak in the exhaust after turbo only.
There is appreciable gains in low rpm response and therefore the more usable power delivery.
In other words, I agree with Leon in that I wouldn't make a mass more power and I am not claiming that the peak power has improved at all. However, I can guarantee that if dynoed before and after you would see a big difference in the power/tourque curve below 3,000 rpm. Which is all I was stating at the beginning.
I can understand that if you ran 30-40psi, you may not notice a huge difference because you may be driving the engine in the upper end of the rev range. I run 14psi on my daily drive, so, I don't really exceed 5,000 on a regular basis.
Cheers.

 

[MDK87]

You two bozos probably just sunk a few too many stubbies while you were porting and that why it felt faster. :lol:

 

[White Knight]

Cheers mo, always count on your support.... I'll give you a ride when we meet at willowbank...

 

[grndsm]

Actually, a small exhaust leak, would do just that: increase the time it takes to build boost! But if will not necessary lower your boost at high RPMs.

But to take this a step farther, one of my friends, who daily drove his Eclipse, kept blowing his manifold (ported) to turbo gasket (it would happen to him every 15k miles or so), because he no longer had a fire ring. So he did something that most people considered crazy: he got a new, non-ported manifold and turbine housing (so that he re-install the fire-ring!).

He did't feel any reduction of power and went on to set his personal best on non-ported components (11.7 @116) on 26psi and 16G turo

He thinks that he probably lost a few HP, but considers it a good enough trade for having stopped his blown gasket problem.

I am still porting them for people who ask me to do it, but I usually tell them not to do it unless they are looking to make over 500hp or so.

My personal race cars always have ported manifolds but my daily drivers do not.

Lastly, I will agree with with Benny that stock manifold is VERY good! I personally have ran 9's on a ported manifold (and made 613whp) as have many others. The only reason to upgrade from it, is when you run a HUGE turbo, which can't be coupled to OEM manifold! Or... If you have a show car and need something shiny

 

[Benzo4gT]

I'm impressed that so much power can be made on a stock manifold, I never knew they could do that well when the right stuff is hanging off the side of them.

I'm not sure I understand how a post turbo exhaust leak will negatively affect boost when the first thing a lot of guys do at the drags is drop the exhaust.

 

[grndsm]

Did I say "post turbo"? I only see mentioning a leak before the turbo. After the turbo, you want the biggest "leak" possible . BTW one common leak that often goes unnoticed is through a waste gate flapper valve.

To be honest, I only deal with race cars which do not care about what happens below 3000 rpm. . But you must have seen what happens to manifold to turbo gasket when you do not use a fire-ring: given enough time, it cracks and starts leaking!

As to why I did kept doing so many port jobs, it was a SUPER popular mod in the late 90's! And you could make decent money on it. Back in 96, I had my manifold ported by one of the "big name vendors" and was shocked at poor quality of their port job. So as my business grew, I stated doing my own, much better port job (I used a CNC Milling machine to hog away most material and then would another hour with a die grinder). But with time, I saw the downside of this mod (blown gaskets) and started talking customers out of porting unless they were going for over 500hp.

However FP cast manifold became very popular option about 8 years ago. But I am still running ported stock manifolds...

 

[Benzo4gT]

Actually, a small exhaust leak, would do just that: increase the time it takes to build boost!

Sorry, took that to mean exhaust system, not manifold or turbine housing.

However FP cast manifold became very popular option about 8 years ago. But I am still running ported stock manifolds...

A sense of satisfaction always comes with DIY

 

[evo-gsr]

I hate to disappoint you and I certainly do not want to bash Benny's fine port work, but whatever you are feeling is NOT a result of porting. I have ported 30-40 of these manifolds over the 17-18 years I have been in DSM modding business and I never saw anyone "feel" the results if such porting. Bare in mind that most of my customers were running 20-30 psi (1.3-2 bar) and were MORE likely to benefit from such porting, as they were closer to maximizing manifold's capacity.
At best, you are getting 3-5% of power increase (more likely 1-2% at only 10 psi) while you need at least 10% to actually "feel the extra power by the seat of your pants".
More likely, you had an exhaust leak before the turbo, which was coincidently repaired when you swapped parts and/or gaskets. Such repairs do yield very notisable results.

I tend to agree with this also.

 

[evo-gsr]

You two bozos probably just sunk a few too many stubbies while you were porting and that why it felt faster. :lol:

And this.

 

[Benzo4gT]

HAHAHA, well at least one member on the forum is happy with the work :thumbsup:

Probably should start keeping things to myself.

I got the flow figures from the head I ported and..................Ahhh, nearly got me..............you guys

 

[evo-gsr]

Im not putting **** on your work mate.

 

[MDK87]

Constructive criticism is a good thing Benno.
At the end of the day you'll decide what to do to your own car anyway, but having advice offered to you is never a bad thing.
I don't think anyone here is putting **** on your work. Except Jamo, he is.

 

[evo-gsr]

I think you are getting dyslexic in your old age Mo.....

 

[evo-gsr]

http://www.4gtuner.com/topic/24456-rvr-hyper-sports-gear-bonnet-white/#entry302785


Another example above ^ lol !

 

[MDK87]

Hahaha bloody hell I give up. I'm going to go back into my corner and talk to the magical voices.

 

[grndsm]

Well, the more you port, the lighter it gets!

I adapted a sandblasting cabinet for porting to keep the metal shavings off my body. My wife was getting fed up with speckles of rust in the shower . And it worked like a charm! I just emptied it, after all these years... It must have had over 3kg of metal shaving in it!

In the later years, most of my porting was focused on reducing or eliminating boost creep. So I would port the internal WG hole and the WG passage of the O2 housing.

 

[Benzo4gT]

I was just being cynical guys, apparently it happens more with old age :wacko:

Well, the more you port, the lighter it gets!

250 grams at a time, that's good for 3.1/100ths of a second!

To sum up and avoid confusion: ↓↓

Exhaust leak before work = None

Increase in overall horsepower = None

Positive manifold pressure noticed at lower RPM = yes

Earlier boost noticed = yes

This was an experiment that has yielded some results when the car is at the start of the threshold, that is all that has been claimed, it's not my car, but results are results, no matter how insignificant they are to those that see overall

hp rather than improvement in the early stages of spool. Not many people think about or are concerned with a slight improvement at these low rpms

At full boost there is no difference, Ian knows his car and has had it for quite a while as well as other 4g63s, he also knows what a pre-turbo leak sounds like and

A decade or so ago I would have regarded these results as worthless, but reducing the time it takes to come on boost by a few hundred RPM is success in my books.

To each their own though ^_^

 

[4piknup]

As long as the customer is happy, benzo.

 

[grndsm]

You should do a logging run before and after and then superimpose the two boost curves. Pretty easy to do with any dataloger. That takes away the subjective nature of human observations.