[abhik]

Originally Posted by The Wolf

Surprise, its the same engine that comes with the car I still have in there ;-)

You call that a surprise...Heart Attack or Brain (un)Twister would be more appropriate...LOL!

[RedMM340]

Originally Posted by cancerm

Hello Sir
Just wanted to know would a bigger throttle body have a drastic effect on the fuel economy.

Rgds

Hi there,

Here's my 2 cents worth on this issue.

It will reduce fuel economy.

If you want to maximize the fuel economy, stay away from all performance modifications. Doing performance modifications will almost always have a negative effect on fuel economy, reliability, and pollution.

Best Regards,

Gaurav

[Shan2nu]

If you want to maximize the fuel economy, stay away from all performance modifications. Doing performance modifications will almost always have a negative effect on fuel economy, reliability, and pollution.

I saw an increase in FE after i got my Vtec modified. Some basic mods like filters, headers and free flow exhausts can improve FE since they increase cylinder scavenging, which reduces the amount of burnt air getting trapped within the cylinder. Which means there is more room for the next lot of fresh air, when it gets sucked in during the intake stroke.

Moreover, a stock setup actually chokes the engine, preventing it from functioning efficiently. By reducing backpressure you reduce the resistance the engine has to overcome during the exhaust stroke.

Finally, it comes down to your driving style. You can have the most FE car in the country but you'l never get the most out of it unless you drive it the way it should be driven.

Pollution wise yes, removing the cat-con makes the exhaust more pollutant. But there are ways you can have a modified car with the catcon still intact.

Speaking of reliability, it depends on who you get the car modified from and what sort of parts have gone into the modification. I've seen some people go through a real nightmare, getting their cars modified.....but i've also seen some really powerful indian cars being as reliable as when they were stock.

Shan2nu

[cancerm]

Originally Posted by The Wolf

No, not really! You are just generating a wee bit more power a little lower down the rpm band at part throttle so it will not affect your fuel efficiency as long as your driving style remains consistent.

Thank You sir for ur reply
I have 1.5 EXI OHC type 2 with stage 1 mods & RD ECU - RD 0601
Would it be a good idea to have a bigger TB considering it will be my daily driving car. if yes may I pl know the apprx costing of the TB & the source to procure it too.

Rdgs

[The Wolf]

Originally Posted by cancerm

Thank You sir for ur reply
I have 1.5 EXI OHC type 2 with stage 1 mods & RD ECU - RD 0601
Would it be a good idea to have a bigger TB considering it will be my daily driving car. if yes may I pl know the apprx costing of the TB & the source to procure it too.

Rdgs

Oh its absolutely fine mate, it isnt going to do any bad at all!!! Next time you come to Race Dynamics tell Karthik that I suggested you this...it will be taken care of from there!

Originally Posted by RedMM340

Hi there,

Here's my 2 cents worth on this issue.

It will reduce fuel economy.

If you want to maximize the fuel economy, stay away from all performance modifications. Doing performance modifications will almost always have a negative effect on fuel economy, reliability, and pollution.

Best Regards,

Gaurav

I beg to differ on your 2 cents again my man...

Dude, I think you need to work on 2 things to start with;
1. Understand basics of tuning- scientifically/your personal experience and not something you have heard or read.
2. Try to differenciate between tuning that will effectively improve your existing mass production unit's efficiency and compromised performance modification where you modify to improve performance compromising FE, ride quality etc.

Once you figure these 2 things out as well as we have, you will know exactly where we are coming from.

No offence mate

[khan_sultan]

Ok, to all the gurus out there with 'n' number of perspectives. I ask again:

Will a standalone ECU -- like the Race Dynamics RD 0601, increase the low end pickup/torque in the following 2 scenarios?

1. The car is ABSOLUTELY stock
2. The car has basic mods like: CAI, FFE and polishing ONLY

Cheers,

[The Wolf]

Originally Posted by khan_sultan

Ok, to all the gurus out there with 'n' number of perspectives. I ask again:

Will a standalone ECU -- like the Race Dynamics RD 0601, increase the low end pickup/torque in the following 2 scenarios?

1. The car is ABSOLUTELY stock
2. The car has basic mods like: CAI, FFE and polishing ONLY

Cheers,

Very short and precise answer, YES!

Originally Posted by abhik

You call that a surprise...Heart Attack or Brain (un)Twister would be more appropriate...LOL!

LOL, if you think so mate! Its taken a lot to get there I promise you, money and waiting period is just a couple to name

[cancerm]

[quote=The Wolf;888147]Oh its absolutely fine mate, it isnt going to do any bad at all!!! Next time you come to Race Dynamics tell Karthik that I suggested you this...it will be taken care of from there!


Thank You Once again for the reply
Well any idea WRT to costing of the TB & where to procure it from

Rgds

[abhik]

Originally Posted by Shan2nu

I saw an increase in FE after i got my Vtec modified. Some basic mods like filters, headers and free flow exhausts can improve FE since they increase cylinder scavenging, which reduces the amount of burnt air getting trapped within the cylinder. Which means there is more room for the next lot of fresh air, when it gets sucked in during the intake stroke.

Moreover, a stock setup actually chokes the engine, preventing it from functioning efficiently. By reducing backpressure you reduce the resistance the engine has to overcome during the exhaust stroke.

Finally, it comes down to your driving style. You can have the most FE car in the country but you'l never get the most out of it unless you drive it the way it should be driven.

Pollution wise yes, removing the cat-con makes the exhaust more pollutant. But there are ways you can have a modified car with the catcon still intact.

Speaking of reliability, it depends on who you get the car modified from and what sort of parts have gone into the modification. I've seen some people go through a real nightmare, getting their cars modified.....but i've also seen some really powerful indian cars being as reliable as when they were stock.

Shan2nu

I would second this bro, and adding on to this, FE drop is experienced only because your way of driving changes to a more aggresive style when you hear a beautiful induction roar from a high-flow filter or the symphony of the exhaust note, so all you do even standing idle is REV and REV to hear the above yourself and also let others know of your mods, hold on to gears at higher RPMs etc. But that results in loss of FE which you only realise later on. If you maintain a similar rhythm of driving as sanely as you did before the mods them you will see that the engine is less stressed and FE has increased.

[abhik]

Originally Posted by The Wolf

LOL, if you think so mate! Its taken a lot to get there I promise you, money and waiting period is just a couple to name

I know man, i am thinking of an engine transplant myself and when i actually got down to thinking apart from the two factors you mentioned there were a tons of other things that cropped up.
All the very best to you dude!cheers: Just wondering what you would come up with when you Turbocharge the VTEC. And make sure you inform me in advance so that i can get someone to catch hold of me when i faint after looking at the figures.

[rks]

Originally Posted by RedMM340

If you want to maximize the fuel economy, stay away from all performance modifications. Doing performance modifications will almost always have a negative effect on fuel economy, reliability, and pollution.

I agree to a certain extent here, the key words being "almost always". The stock setup has been extensively tested and optimized by the car manufacturer and it takes a lot of expertise to modify this setup keeping in mind all the factors you have mentioned, namely, FE, reliability and pollution.

However, there are some safe "mods" that can be done, given your specific requirements. For a car like old Honda City, I would unhesitatingly do the following:

1. Go for alloy wheels that are maybe 1/2 to 1 inch wider (i.e., if stock wheels are 5J, go for 5.5J or 6J alloys). Make sure the alloy specs are correct, so that there are no vibration or braking problems.

2. Keep stock size tyres, but get good tubeless tyres of sufficient (but not too high) speed rating. Here I am assuming that the stock size tyres can be fitted on wider alloys without violating the tyre manufacturer's requirements.

3. Overinflate the tyres by up to 5 psi, as suggested by Wolf (and which I am practising with great effect for my Santro). Obviously you do pay a penalty in ride comfort here. But the wider alloys plus the overinflated tyres will give terrific handling and a noticeable increase in pickup. The grip will also improve because of the wider wheels.

4. For a car like old Honda City, which would obviously have done at least 50000 kms, I strongly recommend shifting to a high octane petrol equivalent to Speed 97 (I know Honda doesn't recommend this, but I fail to see why). The high-octane petrol should give more than a noticeable increase in performance for a car with a high compression ratio (OHC's should be approx. 10:1 or higher). But you may only see the full effect after running about 5000 kms because the ECU needs time to adjust the ignition timing for optimal performance. Here is where the sophisticated stock ECU will score over most non-stock ones. That is why I strongly recommend not to change the ECU from stock. The car should also have knock sensors for this idea to work, and I am assuming OHC has them.

5. Regularly service the car (replace air filter every 5000 kms) and also pay attention to injector/throttle body cleaning and engine flush.

I am willing to bet that the FE will eventually increase by as much as 1-2 km/lit, given the same driving style as before. So if you are lucky, you will end up recovering much of the extra cost of high-octane premium fuel. The car's peformance should improve sufficiently for enthusiastic highway driving (but probably not enough for the race track).

I personally have done all of the above on my Santro and I can tell you for sure that my car outguns its stock counterparts plus gives me an increased FE of 0.5 to 1 km/lit (my estimate). I do not want to meddle with any other stock components like air filter, exhaust or catcon because I do not have the expertise myself and I do not trust the dealer to understand the changed maintenance requirements when I give the car for service.

[RedMM340]

Originally Posted by rks

I agree to a certain extent here, the key words being "almost always". The stock setup has been extensively tested and optimized by the car manufacturer and it takes a lot of expertise to modify this setup keeping in mind all the factors you have mentioned, namely, FE, reliability and pollution.

However, there are some safe "mods" that can be done, given your specific requirements. For a car like old Honda City, I would unhesitatingly do the following:

1. Go for alloy wheels that are maybe 1/2 to 1 inch wider (i.e., if stock wheels are 5J, go for 5.5J or 6J alloys). Make sure the alloy specs are correct, so that there are no vibration or braking problems.

2. Keep stock size tyres, but get good tubeless tyres of sufficient (but not too high) speed rating. Here I am assuming that the stock size tyres can be fitted on wider alloys without violating the tyre manufacturer's requirements.

3. Overinflate the tyres by up to 5 psi, as suggested by Wolf (and which I am practising with great effect for my Santro). Obviously you do pay a penalty in ride comfort here. But the wider alloys plus the overinflated tyres will give terrific handling and a noticeable increase in pickup. The grip will also improve because of the wider wheels.

4. For a car like old Honda City, which would obviously have done at least 50000 kms, I strongly recommend shifting to a high octane petrol equivalent to Speed 97 (I know Honda doesn't recommend this, but I fail to see why). The high-octane petrol should give more than a noticeable increase in performance for a car with a high compression ratio (OHC's should be approx. 10:1 or higher). But you may only see the full effect after running about 5000 kms because the ECU needs time to adjust the ignition timing for optimal performance. Here is where the sophisticated stock ECU will score over most non-stock ones. That is why I strongly recommend not to change the ECU from stock. The car should also have knock sensors for this idea to work, and I am assuming OHC has them.

5. Regularly service the car (replace air filter every 5000 kms) and also pay attention to injector/throttle body cleaning and engine flush.

I am willing to bet that the FE will eventually increase by as much as 1-2 km/lit, given the same driving style as before. So if you are lucky, you will end up recovering much of the extra cost of high-octane premium fuel. The car's peformance should improve sufficiently for enthusiastic highway driving (but probably not enough for the race track).

I personally have done all of the above on my Santro and I can tell you for sure that my car outguns its stock counterparts plus gives me an increased FE of 0.5 to 1 km/lit (my estimate). I do not want to meddle with any other stock components like air filter, exhaust or catcon because I do not have the expertise myself and I do not trust the dealer to understand the changed maintenance requirements when I give the car for service.

RKS,
Glad that you did get my point. Yes the key is "almost always".

The mods that you suggested are absolutely beneficial to fuel economy and are make sense. Going to alloy wheels instead of steel rims will lighten the vehicle weight and improve suspension dynamics. Using tire widths and diameters close to stock will not affect stock mileage, and keeping a +5 psi over stock will improve mileage and performance. Most auto owners manuals will specify a +5 psi for high speed running. In fact Mercedes has this stamped on the fuel filler lid.

I don't agree however on the higher octane rating is better theory. First of all, I just do not trust any petrol pumps to be actually selling premium fuel. There is almost no way to verify that the fuel is in fact higher octane, and give the propensity for business owners to make an easy buck, you can almost be assured that the high octane is at best diluted with regular octane.

Now even if you do get high octane, in my experience with many cars that I have driven, is that only the cars that specify 91 octane really need it. This due to the compression ratio, ignition timing, and a number of other factors controlled by the ECU. Cars that specify 87 octane just do not need the higher octane unless the engine knocks under acceleration or high load.

But if you feel that there is a difference with high octane and feel confident that the petrol pumps that you buy from are honest, that is great, and I am glad that it is working for you.

I could not agree with you more about regular servicing. This has got to be the best "performance" tune that really makes a difference.

Not sure what you mean by an 'engine flush'. But if this is a solvent that is poured into the crankcase prior to an oil change, it can cause permanent damage.

Synthetic oil is another performance enhancer that will not harm anything.

Oiled cotton gauze air filters such as K&N is a performance modification that does help reduce the intake restriction thereby improving high rpm performance and low rpm throttle response. BUT, the horsepower gains made by K&N are exaggerated. And the big downside to using these filters is that they do allow in more dust than stock filters. Additional dust will accelerate internal wear and require that you do more frequent oil & filter changes.

Regards,

Gaurav

[rks]

Originally Posted by RedMM340

I don't agree however on the higher octane rating is better theory. First of all, I just do not trust any petrol pumps to be actually selling premium fuel. There is almost no way to verify that the fuel is in fact higher octane, and give the propensity for business owners to make an easy buck, you can almost be assured that the high octane is at best diluted with regular octane.

Now even if you do get high octane, in my experience with many cars that I have driven, is that only the cars that specify 91 octane really need it. This due to the compression ratio, ignition timing, and a number of other factors controlled by the ECU. Cars that specify 87 octane just do not need the higher octane unless the engine knocks under acceleration or high load.

But if you feel that there is a difference with high octane and feel confident that the petrol pumps that you buy from are honest, that is great, and I am glad that it is working for you.

Gaurav,
I have read that for older MPFI cars, which have done at least 50000 kms, using a higher-than-recommended octane fuel could be beneficial, provided that they have a relatively modern ECU and knock sensors. The reason for this is apparently that the effective compression ratio is increased in older cars due to deposits in the engine. I do feel this is beneficial for my car, but this could just be because the Speed 97 that I use is likely to be unadulterated, as compared to normal petrol. I buy the fuel from a company outlet. My car's performance is consistently good, as compared to my earlier experiences with regular petrol at various outlets in Mumbai and Pune.

Not sure what you mean by an 'engine flush'. But if this is a solvent that is poured into the crankcase prior to an oil change, it can cause permanent damage.

Synthetic oil is another performance enhancer that will not harm anything.

Thanks for the info. Now that you mention this, I did read that engine flush can be harmful. Here is a website that explains the dangers:

Do You Need To Flush?

At Sanjay Hyundai in Pune, they do a lot of hard-sell and I am almost compelled to do this every 10000 kms or so. But now that I have become aware of the dangers, I will think twice before using it in future. About synthetic oil, I am not sure that I should go in for them at this stage (with my car having done 75000 kms.

Oiled cotton gauze air filters such as K&N is a performance modification that does help reduce the intake restriction thereby improving high rpm performance and low rpm throttle response. BUT, the horsepower gains made by K&N are exaggerated. And the big downside to using these filters is that they do allow in more dust than stock filters. Additional dust will accelerate internal wear and require that you do more frequent oil & filter changes.

Yes, precisely. This is the reason for my not meddling with the stock air filter or air intake. The higher maintenance demands will probably be mishandled by the service guys and I do not have the time myself to monitor these.