[akas_chauhan]

Originally Posted by megazoid

I did a dyno test for my 2002 OHC vtec a few weeks back and got a power output with a loss of roughly 15%. What however worries me is a major dip in the torque curve around the 3.5k RPM and one that rises thereafter. So, basically I have a nice M shaped torque curve that does not seem right for some reason and one that adversely affects driveability. I have the same mods as GTO's car namely an air filter (Ractive), headers and free flow. The free flow may not be in the best of shape but I am really surprised that there is so much power difference.

Megazoid, Where did you gone through this Dyno test in Bangalore and how much it cost?
Was the test a Chasis dyno or engine dyno test?

If you can put elaborate more on your test it would be helpful to others.
Anyway thanks for sharing the info.

[thedreamcatcher]

Hey GTO, happy that the car is still within family. But must have been a tough decision selling it off. Especially after doing so much on it. I could never have done so.

By the way, how much did the stock car give out in terms of BHP

[S@~+#0$#]

Fantastic read Rehaan and GTO, very informative too.

[GTO]

Originally Posted by thedreamcatcher

By the way, how much did the stock car give out in terms of BHP

Unfortunately, I couldn't get it dyno'ed before the mods, for the simple fact that Karan's dyno wasn't installed yet.

Considering Honda's claim of 106 stock horses at the crank, the Vtec would have probably managed 90 - 95 BHP on the dyno (calculated power at the wheels after a loss of 10 - 15%).

[sumeethaldankar]

A very interesting read.The new owner's lucky to get a car like that.
GTO,when is that civic of yours coming up ?

[megazoid]

Originally Posted by akas_chauhan

Megazoid, Where did you gone through this Dyno test in Bangalore and how much it cost?
Was the test a Chasis dyno or engine dyno test?

If you can put elaborate more on your test it would be helpful to others.
Anyway thanks for sharing the info.

hey,

sorry for replying late. Happened to see the post late. I got the test done at spitfire performance at coimbatore. It was a chassis dyno. I had a suspension upgrade and since the dyno facility was in the vicinity, decided to quickly get it done. Peak torque and power have shifted slightly over the RPM range, but was within expected range. I really did not expect too much benefit from an FFE and filter. But my torque curve dips between 3k and 4k rpm and then rises again to a max value. The only thing that I can't explain is that curve. After seeing GTO's graphs, must say that Iam really really surprised about the gains that he has got from these simple mods.

[MihirC]

Hey GTO/Megazoid, how much it cost to do a dyno test? Also how much time does it take.

[avinash_m]

Originally Posted by Rehaan

A single run is currently quoted at 3,000/- Rs, and better deals are given for those who plan to use it more often.

If you see KS Motorsport's website, they have some additional offers like free first run, discounted second, etc : Welcome to KS MOTORSPORT --->

cya
R

@MihirC: Rehaan quoted the figures in one of his earlier posts in this thread.

[CPH]

Originally Posted by Shan2nu

So whatever is causing this slippage is creating a difference of 5.6% between engine and wheel rpm.

So does this indicate that another 5.6% in addition to the 15% is being lost in the process, due to slipage?

Coz be it wheel spin or clutch slip, the power being transfered from the engine to the ground is being affected.


Shan2nu

The power is being affected. But the losses due to slippage you can't measure as there is no way referencing them.

I know dynomite very well (all performance graphs on my website are done with a dynomite, but I won't tell what site this is because this would be unfair to admin me not being approved so please don't ask) and there should be no reason for the slipping not to stop.

I personally would have repeated the runs till Ican be sure that there wasn't any slipping.

But I don't want to reducule the operators of the dyno as I know damn well how difficult it is to operate a dyno. It looks all straight forward and looks easy, but there is more behind than meets the eye (I might put up a thread if I know where to do this).

BTW a fairly cheap way to get a very accurate reading of the power curve is with the dynolicious software for the ipod.

All you nee to know is the exact weight of your car with all the rubbish one carries around as well as drivers weight.

The acceleration times and terminal speeds on a flat road over a quarter mile are very accurate. We have tested it against the Santa Pod race way quarter mile strip in England.

If you need to check the calculation the ipod makes for evaluating the power on the wheels you can do this from the terminal speed and the acceleration time.

From what I can see from the graph, thias engine has got quite some more potential to get some serious torque out of it.

[avinash_m]

@CPH: Thanks for posting your thoughts. Would really look forward to your thread on the operation of a dyno.

BTW, could you please elaborate a bit more on the 'dynolicious' software and what was it in the power/torque curve that made you think this engine has potential for more?! Would be very helpful for us newbies.

Thanks,
Avinash

[pranavt]

Originally Posted by megazoid

hey,

sorry for replying late. Happened to see the post late. I got the test done at spitfire performance at coimbatore. It was a chassis dyno. I had a suspension upgrade and since the dyno facility was in the vicinity, decided to quickly get it done. Peak torque and power have shifted slightly over the RPM range, but was within expected range. I really did not expect too much benefit from an FFE and filter. But my torque curve dips between 3k and 4k rpm and then rises again to a max value. The only thing that I can't explain is that curve. After seeing GTO's graphs, must say that Iam really really surprised about the gains that he has got from these simple mods.

Is your OHC a pre-2002 model? Perhaps that would explain the torque hump/dip as the fuel/timing maps were changed in the 2002+ OHC VTECs. Could even be a fault in the dyno or tyre-slip. Can you post the graph here?

[CPH]

Originally Posted by avinash_m

@CPH: Thanks for posting your thoughts. Would really look forward to your thread on the operation of a dyno.

I will do it soon Avinash. Just wonder where to place it.

Originally Posted by avinash_m

BTW, could you please elaborate a bit more on the 'dynolicious' software

The dynolicious software you can download from the Apple website.

To operate it you need a stretch of road that is straight and rather flat.

You have t place the ipod level and after setting it you drive off till you reach the quarter mile (the ipod knows when you have reached it).

Best is to repeat the run in the opposite direction and take the average of the 2 runs.

It gives you the acceleration times in mph increments, quarter mile time and terminal speed as well as peak power and a power graph.

Originally Posted by avinash_m

what was it in the power/torque curve that made you think this engine has potential for more?! Would be very helpful for us newbies.

The bottom end torque delivery is quite good, which looks to me because of the improvement of the air intake even if it can be improved. But I am not convinced that the reading at the bottom is correct.

Japanese normally aspirated engines are known to be not great on torque. Under 70lb ft per litre is nothing great. An just above average European n/a engine does reach at least 80lb ft per litre. Achieving between 85 and 90 lb ft is quite good. Above 90 is very hard and 100 hasn't been reached yet.

As I am not very familiar with the engine version you have over your end I need to know a bit more about the engine to unleash the full potential.

Well, I think it is about time that I come over. lol

[pranavt]

Originally Posted by CPH

I will do it soon Avinash. Just wonder where to place it.



The dynolicious software you can download from the Apple website.

To operate it you need a stretch of road that is straight and rather flat.

You have t place the ipod level and after setting it you drive off till you reach the quarter mile (the ipod knows when you have reached it).

Best is to repeat the run in the opposite direction and take the average of the 2 runs.

It gives you the acceleration times in mph increments, quarter mile time and terminal speed as well as peak power and a power graph.



The bottom end torque delivery is quite good, which looks to me because of the improvement of the air intake even if it can be improved. But I am not convinced that the reading at the bottom is correct.

Japanese normally aspirated engines are known to be not great on torque. Under 70lb ft per litre is nothing great. An just above average European n/a engine does reach at least 80lb ft per litre. Achieving between 85 and 90 lb ft is quite good. Above 90 is very hard and 100 hasn't been reached yet.

As I am not very familiar with the engine version you have over your end I need to know a bit more about the engine to unleash the full potential.

Well, I think it is about time that I come over. lol

If you're familiar with old Honda Civic single cam engines, you'll be familiar with this. It's a D15 block with a D16Y8 VTEC head and Y7/Y8AT intake manifold.

[avinash_m]

Originally Posted by CPH

I will do it soon Avinash. Just wonder where to place it.

You can place it in the Technical Stuff section, if I am not wrong. The mods can help you with this one.

Originally Posted by CPH

The dynolicious software you can download from the Apple website.

To operate it you need a stretch of road that is straight and rather flat.

You have t place the ipod level and after setting it you drive off till you reach the quarter mile (the ipod knows when you have reached it).

Best is to repeat the run in the opposite direction and take the average of the 2 runs.

It gives you the acceleration times in mph increments, quarter mile time and terminal speed as well as peak power and a power graph.

Nice! A friend of mine has an Iphone (hope it'll work on the phone as well).
Let me try this one. Will surely post my findings.

Originally Posted by CPH

The bottom end torque delivery is quite good, which looks to me because of the improvement of the air intake even if it can be improved. But I am not convinced that the reading at the bottom is correct.

Correct me if I am wrong here but the bottom end improvement has more to do with the FFE (headers) than the air intake, please elaborate if otherwise?!

Avinash

Originally Posted by pranavt

If you're familiar with old Honda Civic single cam engines, you'll be familiar with this. It's a D15 block with a D16Y8 VTEC head and Y7/Y8AT intake manifold.

Thanks for the info pranav. I was about to start my search on this one.

Avinash

[pranavt]

Originally Posted by avinash_m

Correct me if I am wrong here but the bottom end improvement has more to do with the FFE (headers) than the air intake, please elaborate if otherwise?!

Avinash



Thanks for the info pranav. I was about to start my search on this one.

Avinash

Even the diameter and shape of the intake setup (manifold, runners, intake pipe, etc) decide the level of improvement or dictate the optimum powerband. It's a complete system and everything affects the power produced at X rpms.