DYNO RESULT: GTR Before & After HKS GT2530

[lwells]

Yeah I am serious. Go a high flow if you want, but pumping out poisonious gasses that would otherwise be caught by the cat is not helpful to anyone. Just my IMHO.

Plus there is also the issue of back-pressure...

LW.

[EnricoPalazzo]

less back pressure better with turbs.

also really hi flow cats are really a crock i believe.

[Steve]

If you were so worried about the environment, drive a solar powered car. Cats only have a very short effective life, after which they do very little. As soon as you change anything on your car, the emissions profile will change, so you best not do any performance mods either.

The single biggest contributing factor to vehicle emissions is poor (or no) servicing - check out the DOTARS website, have a look at the national inservice study into vehicle emissions - 2 years and 2 milliion dollars spend to find out that if they could service the entire fleet of cars on the road at the moment, it would have a 10 TIMES greater effect on vehicle emissions than all the new cars sold (during the the year of the study) being ZERO emissions.

If cats were so damn important, why dont bikes have them, and why is it trucks, that spend arguabley more hours on the road and burn massive amounts of fuel, can spew smoke into the air quite legally.

Not having a go, but sometimes I think opinions are founded on mis information and scare mongering

Not saying you fall into this category, but often such misinformation is instigated by over opinionated mis informed minority groups whos basis is made from too many people with too much time on their hands and no lives trying to do something 'meaningful' with their lives.

This usually results in making life more difficult for the average guy by causing new rules to be made all the time. There was a time when you could do what you wanted, soon you wont be able to do a bloody thing without breaking some stupid rule instigate by people trying to justify their own existance by trying to take on the consciousness of the free world.

/rant

appoligies for the whore, wrong button was pushed. (note to self, stay away from buttons)

[GTRgeoff]

A class I did on marine environment at Uni showed that mans contribution to greenhouse gasses is such a pitiffully small amount compared to what is produced from the oceans floors that there is just a marked interest by those who make a living scaremongering and spending research dollars that keeps it going. Video of people refuting the greenhouse theory 15 years ago followed by their later expert comments that it does exist (while spending said funding) was certainly humiliating for them when they were questioned on their new stance. There is no money in proving something isn't happening so they ummm manipulate the statistical data to generate the required result.

I'm not saying throw trash and be asolute filth, but the emissions aspect is mostly bunk. The worlds best simulators say that due to the amount of natural greenhouse gasses produced we should be dead.

Wanna know what the "smog" is, primarily?

Tyre particulates....rubber and silica. very little is smoke.

My cat rests in peace!!!

[lwells]

Geoff: I completely agree that servicing is a very important aspect of maintenance - if your vehicle is effeciently using all the ingredients in the combustion process and is thus spewing them out the tail-pipe, that helps no one.

However, cats do serve a purpose. They are not going to save the world as car's by their very nature of burning fossil fuels are polluters, however, every little bit counts. The less carbon monoxide, hydrocarbons and nitrogen oxides released, the better.

If people want a very general understanding of the purpose of a cat, see: http://auto.howstuffworks.com/catalytic-converter.htm

I imagine the lack of cats on trucks has much to do with poor regulation as anything else. There was a belief that desiel powered vehicles don't require cats, so many of the desiel vehichles on our roads do not have them (and trucks are largely desiel powered). As for motorcycles, I have no idea. I would imagine it has a lot to do with their small capacity/high output nature that means they are not deemed to be as "bad" as cars, and thus not subject to the same restrictions.

Enricco: yes, hi-flow cats are largely a joke, but that's not because such a device is possible, but rather faulty design or just wanting to rip-off people. The catalyst parts of the cat are very expensive, and hence used sparringly. Cats -- as fitted by manufacturers -- are designed to a price point; combined with tight regulation this means they are often very restrictive on air flow. Unfortunately a number of aftermarket companies have been exploiting this fact by selling so-called "hi-flow" cats that are totally ineffective.

skylinegeoff: I am not here to preach that the world is going to end tomorrow. However, I think its very hard to argue that there isn't a link between the emission of so-called "greenhouse gasses" and environmental degradation. The fact that cars are one of the biggest producers of emissions in turn means they are also one of the worst offenders.

You are also quite wrong that there is no money in disproving the supposed environmental impacts of fossil fuel burning. There are a number of industry sponsored bodies that employ scientists to disprove the environmentalist cause; infact I would argue that it is easier to get industry funding to support the continuing burning of fossil fuels than it is to get research dollars to support the "greeny" position.

Anyway, that's just my view and its clogging up this thread which is not suppose to be about cats, and for which I am sorry. I still strongly believe that cats serve a purpose and should be maintained and not removed; every little bit helps.

LW.

[Merli]

LaL - I've only got the stock GTR boost gauge so can really only go by that

but generally boost is starting to come on around 3k, and on full by 4k in most gears...

That's what a stock GTR should be doing. Boost starts to build at about 3000rpm, and then it "hits" at 4000rpm (1 bar-ish)

lwells: Can you please elaborate a little more about why "high flow" cats are ineffective? Do you mean by the fact that they're just as restrictive as the smaller diameter stock cats or that they aren't as effective at removing pollutants?

[GTRgeoff]

skylinegeoff: I am not here to preach that the world is going to end tomorrow. However, I think its very hard to argue that there isn't a link between the emission of so-called "greenhouse gasses" and environmental degradation. The fact that cars are one of the biggest producers of emissions in turn means they are also one of the worst offenders.

You are also quite wrong that there is no money in disproving the supposed environmental impacts of fossil fuel burning. There are a number of industry sponsored bodies that employ scientists to disprove the environmentalist cause; infact I would argue that it is easier to get industry funding to support the continuing burning of fossil fuels than it is to get research dollars to support the "greeny" position.

LW.

Yeah I wouldn't know wouild I. Oh well, I'll just burn the undergrad and masters degrees in mechanical engineering...plus ignore the years of experience, the mechanics qualifications and the wasted effort and millions of dollars of emissions testing and wind tunnel testing large vehicles cos someone read something on the internet not subject to broad peer review and substantiation.

man produces around 4% of the worlds ozone destroying greenhouse gasses, unless the oceanographers are wrong.

On the boost subject, my 25t's similar to that, as the boost builds then the punch at 4000 is enough to blow rwd traction in third on most road surfaces. I would like a smoother transition so maybe a twin setup might be the answer. My modded turb is pretty laggy though, enough so total stockers get away out of real tight corners...well for a little bit anyway.

Wonder if a RB26 exhaust manifold will fit? Anyone want to donate an unused stock set for a few weeks?

[Merli]

GTR manifolds won't fit on an RB25. Different bolt positionings.

I would try a smaller exhaust housing before changing to twin turbos Geoff.

[Morgs]

My car dosen't make fullboost to 4500rpm at least, and its stock..

[lwells]

lwells: Can you please elaborate a little more about why "high flow" cats are ineffective? Do you mean by the fact that they're just as restrictive as the smaller diameter stock cats or that they aren't as effective at removing pollutants?

Sorry, I have either not explained myself well or you have misinterpretted what I have said. What I was getting at is there has been a number of complaints about supposed "hi-flow" cats that, if anything, are worse than the stock units. Basically they are just shoddy ripoffs.

However, my general point was that there is nothing wrong with a hi-flow cat when properly implemented. As they are made to a higher price point, they should have more of the catalyst within them (ie. a bigger surface area) through which the exhaust gasses pass, hence being less restrictive.

Hope that clears it up

skylinegeoff: Sorry, but I guess we agree to disagree. I have seen plenty of research that argues that fossil fuels are significantly contributing to environmental degredation. I am not blind to the fact that there is evidence to the contrary, just from what I have read the environmental damage arguement seem more persuasive to me.

I should point out that when I said "[t]he fact that cars are one of the biggest producers of emissions" I thought it was fairly obvious I meant man-made (or "non-natural") sources.

Anyway, can we agree to disagree and stop clogging up meshmesh's thread? I want have anything more to say on this subject in this thread -- I promise

LW

[EnricoPalazzo]

Yep iwells hit the nail on the head. Most Hiflow cats are a joke and are equally as restictive as stock units. The only true hiflow cat is an empty one

[Steve]

...... I would like a smoother transition so maybe a twin setup might be the answer.....

Have you tried tuning the ramp onto boost? Most places will give all you can get, and try to bring boost on as hard and quick as possible.

If you wanted a more progressive ramp onto boost, free up the exaust side as much as you can (if you havent already), then get it retuned so its not so violent:)

If you have done everything to free up the exhaust side, it may be worth going to a smaller turbine housing to bring the point that you are making boost in a bit earlier - if the compressor will allow it before surging.

[Snowman]

Hi Jack... Gerald seems real excited about your car and said the same thing about comparing the two. I believe the dyno should be up and running as very late this avo, so once the boys are ready I'll drop it in next week so we can compare..   So glad to have the car back now it's your turn, but I'm sure you'll be rapped.

PS: Be careful what you say infront of the snowman, he's on a mission of attack... I hear his going for the same set up as Leewah's but even more power... I heard him and gerald talking numbers like 700kw at the rears.

Haha - don't listen to him. What the hell would I do with 700rwkw's on a track car? No Im going to aim for basically the same power output of both Mesh and Jag (around 350rwkw) but am going for a 3rd approach. I'm really looking forawards to comparing all 3 of our cars at the end as a lot of our mods will be similar but our turbo options are all different.

[GTRgeoff]

I'm starting to think a more traditional turbo replacement altogether, as these Melbourne GTR guys can't get away with having all the fun. Short of a split dump, there is not much in the way.

LW no sweat buddy.

Snowie, I could imagine you with 700. It would be like light rain on sandown all the time ..........anyone else having traction problems????Hell it's greasy out there LOL.

BTW I talked to racebrakes.com and GTR Brembo pads will be $160 per axle so don't waste money on the greenstuff. With 700 rwkw you will be spending plenty on pads

[Snowman]

Thanks Geoff - went to racebrakes on Sat and have decided to get Comp 9's ($160) for fronts and Comp 2 rears.

But thats off topic.......

Will speak to you about exhaust manifold on Wed at NDSOC meeting. Might be able to lend you mine in a few weeks.

[Guest INASNT]

U are going for big single aint u snowman?

[matlowth]

Geoff,

The last time I went out to Sandown, I found all the bumps & undulations on the main straight tended to upset the car under power which is bloody scarey at the top of 4th.

Looking forward to getting out there again though (ps. Haven't fitted the HICAS gear yet).

Cheers,

matt

Snowie, I could imagine you with 700. It would be like light rain on sandown all the time ..........anyone else having traction problems????Hell it's greasy out there LOL.

[Snowman]

I would say a nice single - not a big single yes. Aim at being a good responsive car for track but not going a twin low mount option. Be interesting to see how it turns out.

[Snowman]

Geoff,

The last time I went out to Sandown, I found all the bumps & undulations on the main straight tended to upset the car under power which is bloody scarey at the top of 4th.

 

Looking forward to getting out there again though (ps. Haven't fitted the HICAS gear yet).

 

Cheers,

 

matt

Matt - which club are you with? I think a few of us will be there again May 30th with NDSOC.

[GZ R33]

Hi GZ,

That's interesting, can I ask you a few questions?? Thanks

[Disclaimer - I know that dyno's are a close indication and vary substantially according to many variants, and only using this a guide:)]

Just looking at your graph, it seems overly laggy, is this true & how are you finding the 2540's? Have you driven one with 2530's?

With the power fc and cams the boost starts at about 3500rpm and hits full boost at 4500rpm. Without the above they used to come in at 4000rpm and hit full boost at 6000rpm. (Laggy)