"Dude I bolted on 25 BHP" FAQ !!

[chetanhanda]

Ok this thread is for clearing out doubts/misconcepts abt most common boltons, etc etc which are used by BHPIans and feel they make +x amt of BHP

If you are a noob start reading from here...

I've heard lots of ppl saying how they have "modded" their "ride" and are making the extra BHP or handling better which some of us cant figure out how.. probably becoz they are not making that extra BHP

some mods may be useful but at what level of tune the engine should be to actually make a difference is what this thread will cover !!

I'd like to list out the most common one here and describe each one in detail... gurus plz add ur stuff here and lets make this a complete FAQ

1] Plug wires
2] Iridium Spark Plugs, 4 electrode plugs
3] Air filter/CAI
4] Lightened flywheel
5] electric supercharger
6] synthetic oil
7] 97 octane fuel with octane boosters
8] TB spacers
9] Strut braces
10] ECU reflash
11] Low profile tyres
12] free flow exhausts
13] cams

[chetanhanda]

Another topic which creates confusion...
you may have felt that the new mod is faster using ur seat of the pants
dyno.. OK agreed.
but you still may not be faster in the quarter mile/actual track becoz it may have just shifted the power band above or lower in the RPM range or must have created peak power at only a particular high RPM range which is unusable normal condtions.

[v1p3r]

Easiest way to find out, without a dyno, is to do a couple of runs. Either quarter-mile, 1/8 mile, 60 ft, 0-60, or in gear slogs.

Chetan, what is 8] TB spacers? And now way strut braces or low profile tyres are going to help you go faster, atleast in a straight line. And DEFINITELY no way they give you any extra bhp.

You've missed headers. I've seen them give upto 12 bhp on 1.6 litre engines.

[ananthkamath]

Originally Posted by v1p3r

I've seen them give upto 12 bhp on 1.6 litre engines.

On the bum dyno?

No seriously, did you see it on the dyno or seat of the pants?

[chetanhanda]

Originally Posted by v1p3r

Easiest way to find out, without a dyno, is to do a couple of runs. Either quarter-mile, 1/8 mile, 60 ft, 0-60, or in gear slogs.

yes sir..

Originally Posted by v1p3r

Chetan, what is 8] TB spacers? And now way strut braces or low profile tyres are going to help you go faster, atleast in a straight line. And DEFINITELY no way they give you any extra bhp.

..throttle body spacers , they have some kind of grooves in the inner surface, they sit in between the TB and the plenum.
misconception is they will make the fuel mixture more explosive and carry more charge, makes no sense in MPFI as the ECU will descide how much fuel to put.

Originally Posted by v1p3r

You've missed headers. I've seen them give upto 12 bhp on 1.6 litre engines.

yep.. and total of 25 BHP with free flow

[v1p3r]

Originally Posted by ananthkamath

On the bum dyno?

No seriously, did you see it on the dyno or seat of the pants?

Dyno chart printout.

[ananthkamath]

Originally Posted by v1p3r

Dyno chart printout.

can you post the link or something.

[v1p3r]

Don't have it, sorry.

[ananthkamath]

I can tell from what I've seen of the following (talking more about how the car feels, not how much hp it makes):

4) Lightened flywheel

This will hurt on a stock engine. A lightened flywheel by itself will NOT increase RPM or HP. It will only increase throttle response at higher RPM (what is known as a livelier engine). If you add one to a stock engine, it wont rev any higher and will only lose torque in the low-end.

13) Cams

These can add anywhere between 10% to 20% by themselves. For the more extreme profiles, head work is mandatory. CR increase is mandatory or same effect as above will manifest itself.

My own take on this is:


The engine is a system. Unless you make everything work in harmony with everything else, you wont see any increases without losing somewhere else. The practical manifestation of this is that, if for example you "bolt-on" an intake, pod filter and exhaust, you will NOT see full gains unless you make changes to timing and carburetion. Similarly, if you bolt on a cam without throwing in an adjustable cam adjuster, you will NOT realize the full gains of the cam.

[v1p3r]

Originally Posted by ananthkamath

The engine is a system. Unless you make everything work in harmony with everything else, you wont see any increases without losing somewhere else.

I agree. I wish some people would understand this.

Ananth, the magic of ECU controlled engines is, to some extent, you don't need to change things. A high-flow airfilter will be a pure bolt-on onto an injected car, whereas you may require upjetting of a carb.

[chetanhanda]

nice start ananth..

1] Plug wires..aftermarket wires they dont make extra bhp on a stock engine. e.g if u are using high rpms for the engine beyond what it was designed for , you may have to upgrade to an aftermarket ignition system.
then at this stage u may need upgraded plugs to handle the extra heat range, also You may be running aftermarket EMS to control the timing etc..
now it woud make sense to use wires (a)which suppress Electo mag interfernce ,Radio freq Inteferece etc etc to prevent noise from disturbing these aftermarket EMS etc and (b)also to handle the extra current which is being used to power the plugs..

upgarding wires and expecting HP and torque is funny and a waste of money on a stock engine.

[v1p3r]

Originally Posted by chetanhanda

upgarding wires and expecting HP and torque is funny and a waste of money on a stock engine.

Tell that to the guys who live and die by MSD and NGK Iridiums!

[chetanhanda]

Originally Posted by v1p3r

Tell that to the guys who live and die by MSD and NGK Iridiums!

something rice like .. got ma wires and bumped my power by 10 BHP ..

[mclaren1885]

Finally the myths on advices on TBHP are coming out .. Infact i was shocked to see people recommend ignition controllers , spark plugs , 97 oct fuel on stock cars to get more power .. But saying anything would be either jeopardizing harmony or showing that you know nothing amongst the experts who recommend them in scores ..

However these are beneficial in more than one way when the engine is modded to the extreme or somewhere near it .. Change of a spark plug resulted in lesser pinging on my car , thats when i realized how spark plugs with different heat ranges work (having run 3 different ranges) .. Change in ignition timing using a cheapster trick further got my pinging down completely .. I suppose thats when you need these mods ??

And i would rather prefer to spend 2k (spark plugs) + wires (3k??) + ignition controller (10k+) = approx 15k on porting/polishing my head OR headers and free flow ..

Originally Posted by v1p3r

Tell that to the guys who live and die by MSD and NGK Iridiums!

Chetan , i am glad that such a topic has surfaced .. Good going .. Regarding the lightened flywheels there is another thread here somewhere .. Shall await your explaination on the rest of the details .. Hopefully this will change the perception of mods on TBHP ..

[Ford Rocam]

Originally Posted by chetanhanda

something rice like .. got ma wires and bumped my power by 10 BHP ..

you will find plenty of them in mumbai !