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Old 2nd November 2010, 17:33   #31
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Originally Posted by salilpawar1 View Post
The overlay is correct, you can compare both the individual graphs for reference.
Why is the 2nd curve starting off at a higher rpm. It also revvs higher before it drops off.
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Old 2nd November 2010, 17:40   #32
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Originally Posted by tsk1979 View Post
it appears that the new exhaust is actually leading to lower numbers than before in the low end of the powerband, the place where you actually wanted the benefit.
We had prepared an overlay too. But considering the glaring difference in rpms reported on the dyno (difference of upto 300 rpm between the three runs), I thought its inaccurate. Note the difference between their start & end points.

As I mentioned earlier, the car's response at low rpms is substantially better. Don't know how much this has to do with how much sharper the throttle has become, and how much to do with an increase in torque (if at all), but she's waaaaaaaaaay easier to drive in traffic. I thought it could be the placebo effect, so had others drive my car. Even they (including a stock Civic owner, and a friendly Parsi Mod who has driven my car off & on) commented on improvement in traffic behaviour. Before, you simply couldn't be careless with the throttle response...it had to be carefully matched to the clutch (which was a royal pain). Now, I drive it like the OHC Vtec in city.

I'm going to get her VBox tested for 0 - 40, 0 - 50, 20 - 60, 30 - 80 times and compare with the same for a stock Civic.

Last edited by GTO : 2nd November 2010 at 17:50.
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Old 2nd November 2010, 17:59   #33
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GTO ..congrats on the exhaust .BTW I can vouch for whatever you say about the exhaust .I have a 7 year old Automech exhaust which was originally mild steel.But after 1.75 L kms the MS muffler was beginning to rust .OnGuru Vivek Bhat's ( of Automech) advice,I opted for a Stainless Steel muffler with piping after the expansion chamber .And my car is back to what it used to do ....growl growl and growl..and as its just a week old...the exhaust note just keeps on getting sweeter.

Also the performance has definitely shown a noticeable difference.
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Old 2nd November 2010, 18:20   #34
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This exhaust may not be helping the civic much in its stock form but I feel will have much more effect as an when he does further modifications like adding a turbo.
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Old 2nd November 2010, 18:38   #35
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@speedsatya hello there! I agree your car sounds wonderful!

Someone please clarify if I'm right or wrong. Torque and revs don't like each other very much. So torquey engines don't rev much (muscle cars and diesels) and revvy engines don't torque a lot :P (rx-7, lancers)

So what I figure is when you're having to slip the clutch with the stock exhaust the engine is not happy pushing so hard and would rather stall.
Whereas thanks to the free flow while there is a slight drop in torque there is a willingness to rev and you can totter along? Did I get that right? (Must do homework if I wanna get my mods ) now I really wanna drive this car! @GTO sir I hope you could oblige me sometime when I get the luck of visiting mumbai!
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Old 2nd November 2010, 21:40   #36
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The same as everyone, I think the 4-5bhp is more due to the cat con removed than the exhaust.

In my FFE on the Alto with headers, the low end actually dropped and the high end improved. This when the FFE was supposed to be for low end. The sound made the car feel peppier initially till I realised the placebo effect.

What I really want to know is why the ABS light came on after the run?
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Old 2nd November 2010, 21:43   #37
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Quote:
Originally Posted by GTO View Post
A reminder : My stock exhaust is up for grabs (free) to any BHPian who owns a Civic. Feel free to PM and pick it up from my place at no cost.

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Originally Posted by nitrous View Post

That catalytic converter alone should cost quite a few thousands.
Not only will it hold value in terms of money, you never know when you might need the stock exhaust. For whatever purpose it may be, whether you decide to sell the car later or if you want to leave out the cat and replace the end can with the stock one, I suggest you keep it.

It might come in handy some day.

Oh and yes, what end-can are you using?
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Old 2nd November 2010, 22:40   #38
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Interesting catcon vs exhaust debate :-) The next guy who mods his Civic (and is in Mumbai or where a dyno is available), please only remove the catcon and do a dyno run for specifics on this aspect.

The overlapped graph actually shows lower torque upto ~5k rpm (though marginal) - and we don't have the real low range where GTO wanted to improve driveability and feels it has improved ... So, w/o dyno charts we were guessing, and w/ dyno charts, we are, err, still guessing somewhat ;-)
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Old 2nd November 2010, 23:17   #39
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Smile Dyno Graph Overlay

Posting another overlay approach of the dyno results.
  1. This overlay is SAME as the one posted in my previous post (post no. 27). It is made by directly merging the dyno results.Honda Civic Dyno Run no.2 - With performance exhaust-gto-dyno-graph-copy.jpg
  2. This is the second overlay. But here I've merged the two graphs taking into account the dyno error. So, the top end figures of the both the graphs are made to coincide at the same RPM. The curves are (obviously) unchanged but only I've shifted them along the horizontal axis to account for the RPM error in the dyno.Honda Civic Dyno Run no.2 - With performance exhaust-gto-dyno-graph-copy2.jpg
Edit: In the second graph, ignore the vertical dotted line at the 6850 RPM mark.

Last edited by salilpawar1 : 2nd November 2010 at 23:20.
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Old 3rd November 2010, 01:02   #40
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Quote:
Originally Posted by Viddy
What I really want to know is why the ABS light came on after the run?
Rear wheels stationary.
Front wheels spinning away to glory. With the input from the sensors, the abs module would have gone crazy.
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Old 3rd November 2010, 01:37   #41
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Hmm. This is interesting. What this basically shows is how well a Stock system actually works. Dad will be Gleaming when he reads this. HE has always maintained that stock is the best you can have........in most cases!
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Old 3rd November 2010, 10:39   #42
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Quote:
Originally Posted by speedsatya View Post
I have a 7 year old Automech exhaust which was originally mild steel.But after 1.75 L kms the MS muffler was beginning to rust
1.75 lakhs ain't bad for an MS exhaust. Best thing about him is that everything is done in-house, personally overlooked by the manager and indoors. My Vtec's job was the first I got from him, and it didn't run a bolt loose in the 3 years I had it.

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Originally Posted by Born2Slow View Post
This exhaust may not be helping the civic much in its stock form but I feel will have much more effect as an when he does further modifications like adding a turbo.
Kutlee was talking about increasing the dia to 2.5 when we go blown (if at all).

Quote:
Originally Posted by valhallen.282 View Post
So what I figure is when you're having to slip the clutch with the stock exhaust the engine is not happy pushing so hard and would rather stall.
I have to sheepishly admit that I did stall her when stock a couple of times. The same has been reported by some other Civic owners on the forum too. Yes, on the stock exhaust, she required very careful throttle / clutch co-ordination in traffic. Now, I can get away even without paying any attention.

Quote:
Originally Posted by vid6639 View Post
In my FFE on the Alto with headers, the low end actually dropped and the high end improved.
Depends on the header design no? The set I bought from Psycho was worth every penny.

Quote:
Originally Posted by lancer_rit View Post
The overlapped graph actually shows lower torque upto ~5k rpm (though marginal) - and we don't have the real low range where GTO wanted to improve driveability and feels it has improved ... So, w/o dyno charts we were guessing, and w/ dyno charts, we are, err, still guessing somewhat ;-)
True. In the newer graph, torque does seem to be marginally lower. Horsepower, on the other hand, seems to be consistently higher...through the revv range.

I think the CC was extremely restrictive and that affected the throttles response big time.

Quote:
Originally Posted by nitrous View Post
Rear wheels stationary.
Front wheels spinning away to glory. With the input from the sensors, the abs module would have gone crazy.
In Akshay1234's car, even the traction control modules must have gone ballistic. He mentioned his TC light stayed on until.....an Italian tuneup was performed.

Quote:
Originally Posted by Cyrus43 View Post
HE has always maintained that stock is the best you can have........in most cases!
Can't argue with that. It's thanks to him that I got my Jeep back on the road with OEM parts. 2 years up and no issues at all.
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Old 3rd November 2010, 12:33   #43
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Quote:
Originally Posted by GTO View Post

Post dyno, the ABS light stayed on in my & Akshay1234's cars. Akshay told me to give her an Italian tune up (i.e. redline); worked like a charm.
Quote:
Originally Posted by nitrous View Post
Rear wheels stationary.
Front wheels spinning away to glory. With the input from the sensors, the abs module would have gone crazy.
Quote:
Originally Posted by GTO View Post

In Akshay1234's car, even the traction control modules must have gone ballistic. He mentioned his TC light stayed on until.....an Italian tuneup was performed.
The exhaust sounds really good, and nice to see it has added power and helped with the lower end.

Thanks for the explanation nitrous, I was too busy worrying about the lights to think of the reason. Thankfully it went off.
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Old 3rd November 2010, 14:54   #44
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Quote:
Originally Posted by lancer_rit View Post
One thing I did not understand is why each of the dyno charts (including your 1st run and that of the other cars)has a different X-axis aka rpm range ? To make an easy comparison, each run should be in the same RPM range, and IMHO, it should start atleast at 2000rpm if not lower.


Secondly, from the 3 charts on your runs, I could not discern any difference in torque/bhp at the lower RPM range ! However, you confirmed that city driving is much easier and pickup is smoother. So, it may have to do with the fact that the RPM range is way too high in the dyno chart to show the difference in the critical path "1000-1700/1800" rpm when the pull is really bad ?
Unfortunately this is a bit of a problem with the land and sea. It has to be preset all the time and overlays have a software bug problem. I have complained quite a few times to Land and Sea, but the problem is not fixed. The have a funny way of referencing the charts.

The dyno charts and GTOs findings on the road might contradict each other, but this does not mean that GTO is wrong with his impressions. What most people frorget is that the dyno is only an aid to determine power, but is not capable of representing the real drive. The load simulation provided by the rollers does not represent reality.

Quote:
Originally Posted by Invinsible View Post
Have you considered do the CAI too ? Getting a reasonably sized air filter should make difference in the low end.
The size of the filter is virtually irrelevant at the amount of air that is shifted in this engine. It is much more important to get the turbulence factors as little as possible and make sure that the filter is not starved of air when the car is moving (due to chassis specific drag) as well as getting the gas spped volme ratio correct as the main issues.

Quote:
Originally Posted by lancer_rit View Post
Please do. As I mentioned, possibility to graph from lower rpm, would have also shown up the improvement you feel driving with the free flow @ low rpm. Also, using the same rpm range for all measurements, will allow a top/bottom easy comparo :-)
It should be done with the same setting for cut off. Otherwise the Kand and Sea will show distorted figures in relation to to base graph it referencesw gthe other to.

Quote:
Originally Posted by Mpower View Post
Is KS able to give you a overlay of old and now hp curves so that we can see where exactly the improvement is
He can overlay, but might hit the above mentioned problem, which is something Land and Sea have to sort.

Quote:
Originally Posted by black12rr View Post
Hmm ,if you are spending 20-25 K on FF ,is 4-5 bhp ok ?. I would expect atleast 10-15 bhp for that money spent (asking more?).Off course the advantage is the low end and growl .I dont care about the growl , but would it be possible to increase the low end without free flow ?
The improvement is absolutely ok for the money spent. 10 to 15bhp is illusive on its own.

Quote:
Originally Posted by Zappo View Post
GTO, I was wondering one thing here. With the CatCon gone do you think you will have a problem in clearing the next PUC certification? PUC certification/testing databases maintain a limit for the exhaust gases for the BS-I, BS-II, BS-III etc. The system catches that using the year of manufacture.

My friend had a problem clearing the PUC with his car when he removed the CatCon as he had some exhaust related issues. The new CatCon was costing him around 18k. He thought he will skip a new CatCon but had to order one finally as his car could not clear the PUC certfication even after 3 attempts at the different testing places. Of course depending on manufacturer, and particularly since Honda engines are anyhow some of the cleanest on earth, may be it will not be an issue for you.
It depends first of all on the state of the engine, whether it will pass the tests. Fuel quality and some other factors have their share too.

Honda engines being the cleanest engines is a myth. There is cleaner engines around and local factors influence the outcome of the tests. The governmental emission tests have only limited meaning to how clean an engine is. To evaluate the pollution levels properly a gas collector is needed and testing with these is very involved. An engine failing the test might be cleaner than one just failing the test. The point for the owners is to get through the emission regulations, which a lot of the engines will pass withjout cat, but most will definitively pass with the cat fitted. And just for the records: Abolishing the cat would be better for the environment, our health and our finances.

Quote:
Originally Posted by pranavt View Post
Brainfart. The intake is on the driver's side. Nonetheless, no bolt-on sets for this engine.
Anything can be made if people will ask for it. Just because demand isn't there doesn't mean it is not worth improving. And from experience I know that there is room for improvement.

Quote:
Originally Posted by nitrous View Post
Congratulations on the 5 bhp.

1.You gained mostly from the removal of the cat con.
2.Don't worry about headers. Honda engines flow very well.
3.I have a feeling there are no SS pipes sold in the steel market with diameter values between 1.75" and 2.0".
My puny 85hp 1.3 now runs the same 1.75" albeit mild steel.
The Fiesta 1.6S 100hp comes with 1.75" exhaust piping from the factory.
And now your 130hp civic is running 1.75" aftermarket SS piping.
Can't a 1.85" be sourced?
Or were you really stressing on the bottom end torque to automech?
A lot of cats aren't as much a restriction as people think. The cat cell itself is usually contributing less to losses than the design of many cat housings.

Just changing the Diameter of the collector pipe is not making a real difference. The collector pipe results from the calculation of the primaries (and secondaries if existing), which in turn are calculated from the cam shaft parameters. By just going up in collector pipe diameter you might gain peak power, but sometimes you might shift the peak power point outside the rpm range, which means that the theoretical power gain is actually a loss in the existing rpm range. Also you often create flat spots, which is the answer of maths when we try to create a system that is mathematically out of balance.

Unfortunately the terms free flow exhaust and back pressure are two totally misunderstood terms.

Quote:
Originally Posted by tsk1979 View Post

So the "increase" in low end driveability could be a placebo effect due to sporty noise.
Not necessarily. The dyno run is no way near the real driving situation and is done on full throttle, which would show different results than on the road.

Quote:
Originally Posted by GTO View Post
We had prepared an overlay too. But considering the glaring difference in rpms reported on the dyno (difference of upto 300 rpm between the three runs), I thought its inaccurate. Note the difference between their start & end points.

I'm going to get her VBox tested for 0 - 40, 0 - 50, 20 - 60, 30 - 80 times and compare with the same for a stock Civic.
Welcome to the problems of the world of dynoing.

It is good to use the Vbox for additional testing. I hope you will integrate thes in future reports, which will give a much clearer indication.

Quote:
Originally Posted by valhallen.282 View Post

Someone please clarify if I'm right or wrong. Torque and revs don't like each other very much. So torquey engines don't rev much (muscle cars and diesels) and revvy engines don't torque a lot :P (rx-7, lancers)
From what you see in terms of cars on the road you seem to be right.

But you aren't right in general. A lot more effort is needed to get the torque with power on normally aspirated engines. To overcome it with static camshaft anglesis very involved. Variable valve timing makes it a bit easier. The new system like the Schaeffer valvae control system employed by Fiat (known as multi air) or or the superior system of FEV Aachen help to widen the window greatly.

However, there is always some compromise to be made.

Quote:
Originally Posted by vid6639 View Post
The same as everyone, I think the 4-5bhp is more due to the cat con removed than the exhaust.

In my FFE on the Alto with headers, the low end actually dropped and the high end improved. This when the FFE was supposed to be for low end. The sound made the car feel peppier initially till I realised the placebo effect.
someone did not consider the cam parameters when making your exhaust.

Quote:
Originally Posted by Cyrus43 View Post
Hmm. This is interesting. What this basically shows is how well a Stock system actually works. Dad will be Gleaming when he reads this. HE has always maintained that stock is the best you can have........in most cases!
I beg to differ. Stock systems are pretty bad in these days. and many of the Honda ones are among the worst alongside some other Japanese. The only system that was beating them was the one on the original Dodge Viper. Supersprint showed them how to increase power by (a ceritifed) 70bhp without loosing any torque! This system later was adapted, which was responsible for the power gain in later Vipers from factory.
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Old 3rd November 2010, 15:18   #45
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Removing the cat to get 4-5 hp more does not seem much power increase. However, if the driving characteristics have improved, it should be worth it.

Indian emission tests are not tough since its all done at idle without loading. Would be interesting to know how the exhaust comes out of emission tests. Since its not that costly, are you planning to get one done ?
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