Top 5 cheap simple ways to make your car go faster

This is just a short generic guide I thought I'd throw together to answer the "how do I make it go faster" questions for the less mechanically minded
1. Strip interior
Its a good all rounder. It'll help with acceleration, braking and cornering. Take out as much as you like. More weight lost the better
Best of all it can be done in an hour or two
Cost: Free
2. Service Clean
While its had one elderly owner and a service history doesnt necessarily mean its performing at its best. A fresh service will help no end but dont stop there clean out all the pipes and electrical plugs. Dont be scared to take them off.. just put them back in the right place. It allows the engine to do its job better.
Cost: Free - £40 approx
3. Brake fluid
Of course brake pads and discs must be renewed when necessary but people often forget is the brake fluid. Dot 3, 4 & 5.1 brake fluid is "hygroscopic" which means it absorbs water. So over time becomes less effectives. Drain and replace this and you'll feel a confidence boosting difference in the brakes
Cost: £15 approx
4. An intake
Although a cheap air filter from argos seems appealing it can actually see you lose hp especially if installed incorrectly. The intake is very carefully designed by the manufacturer for that engine but it is still restrictive. Get a decent sized filter or a direct panel replacement. If you opt for a larger cone filter for example. Pick a cooler spot to mount it. Next to the exhaust is the worst place for it even if it is closest to oncoming air. Once mounted then use a pipe to funnel air into the filter still avoiding heat sources
Cost: Varies £30 approx
5. Exhaust
There's two small things you can do to make your exhaust helpful:
A: The cheapest option. Bring down undet bonnet temperatures by wrapping your manifold in exhaust heat wrap. This aids the intake of cooler air and helps your water coolant too as most rad pipes are by the exhaust
Cost: £20 approx
B: A small backbox. A 5.5inch super duper slash cut chrome full system made by 1000hp.com isn't the way forward. N/A engines need to retain the exhaust backpressure to aid in the 'scavenge' effect which draws air into the engine. A slightly bigger than standard freeflowing backbox will help the gas that needs to escape while keeping the harmonious back pressure throughput
Cost: £50+ approx
 
6. A strong tail wind
7. A steep hill or even better
8. A cliff

Edit: don't waste your time with dot 3 or 4 you may as well spend the extra ad get 5.1 with some braided hoses
 

Enuo

Glorified Electrician
change gearbox oil, often neglected and will reduce parasitic losses.
Advance timing a degree at a time until it starts to pink then back off a half degree until it stops.
Check condition of HT leads, replace if worn will improve engine responsiveness
If you have a carb, get it tuned!
 
Make sure all bearings are good and run free

Service your brakes to ensure they don't stick.

When doing an oil change use an engine flush to clear out any gunk
 

Low Rider

Poindexter
Founding Member
Moderator
Club Member
Wasnt expecting to see the old backpressure myth on your list :(
 
OP
OP
h701micra
Easiest way to prove the exhaust myth isnt a myth is by removing your exhaust. Its basically like having a big full free flowing system... you lose top end power.
I know this as my exhaust undid itself as I was going home one day and I just left it :)
 

frank

Club Member
Easiest way to prove the exhaust myth isnt a myth is by removing your exhaust. Its basically like having a big full free flowing system... you lose top end power.
I know this as my exhauast undid itself as I was going home one day and I just left it :)
thats because you lose the GASFLOW , negative backpressure would be ideal, but the backpressure is an unwanted result of achieving some gasflow
 
OP
OP
h701micra
So you've still got standard relative gasflow and backpressure ;) and the bigger box to allow used gas to escape?
I assumed you had a big lary exhaust system not just a backbox :) which is what I assumed when you said guilty
I should make myself clearer :oops:
 

MicraPRO

Part Of The Furniture
So you've still got standard relative gasflow and backpressure ;) and the bigger box to allow used gas to escape?
I assumed you had a big lary exhaust system not just a backbox :)
Yes thats pretty much it and yes of course its to let used gas escape... Noise!!!
Just a backbox :)
 

Enuo

Glorified Electrician
The slower a gas is moving, the higher a pressure it exerts on its surroundings, the faster the lower the pressure. This is how carbs work, as faster moving air has less pressure and by venturi action draws fuel up. So actually, a bigger exhaust will create more back pressure too, as the exhaust gases are moving slower. So by this you can deduce there is little to no difference. If you go ridiculously small you can find the gases can't escape at a fast enough speed to maintain the same flow capacity as a bigger pipe, but other than that theres no difference, unless you have a specially tuned pulse exhaust system.
 

SirChris

Educated Bodger
6. A strong tail wind
7. A steep hill or even better
8. A cliff

Edit: don't waste your time with dot 3 or 4 you may as well spend the extra ad get 5.1 with some braided hoses
Dont you have to be rather careful when using non manufacture recommended brake fluid. Surely using other types will seep past seals and what not. thought I read that somewhere.
 

Enuo

Glorified Electrician
DOT stands for Department Of Transport, and is an american standard. All DOT brake fluids are fully compatible, and must be to bear the DOT moniker.
 
OP
OP
h701micra
The slower a gas is moving, the higher a pressure it exerts on its surroundings, the faster the lower the pressure. This is how carbs work, as faster moving air has less pressure and by venturi action draws fuel up. So actually, a bigger exhaust will create more back pressure too, as the exhaust gases are moving slower. So by this you can deduce there is little to no difference. If you go ridiculously small you can find the gases can't escape at a fast enough speed to maintain the same flow capacity as a bigger pipe, but other than that theres no difference, unless you have a specially tuned pulse exhaust system.
That makes sense to me in carb talk... they draw more air yet retain the same fuel pressure as there smaller counterparts yes?
So if for example the smaller drew 20cfm @ 5psi and the larger 30cfm @ 5psi.... surely there's a pressure drop per cfm?
Excuse the made up figures :oops:
But still a pulse tuned one is better
 
OP
OP
h701micra
I must point out before we progress; this thread is not aimed at gaining 50bhp overnight for free. Just approx 5bhp max on a budget :)
 

Enuo

Glorified Electrician
No, as long as the mean velocity of the gas remains constant, changing the diameter of the pipe will not change the pressure, you will only chang the mass/volumetric flow rate. Pressure in a continuous flow situation is only affected by velocity, temperature and enthalpy changes (eg burning fuel)
Edit: I think, been a while since I did thermodynamics and fluids at uni
 
brake fluid makes it go faster ???

No but I prefer to stop faster than I accelerate

or is that why you change brake lines? what about the cylinder seals and what not.

Changing the brake lines just makes sense, do you know how old your rubber brake lines are and whether they've been looked after (by not letting the caliper hang freely stressing the line)
 

SirChris

Educated Bodger
No but I prefer to stop faster than I accelerate

over rated

Changing the brake lines just makes sense, do you know how old your rubber brake lines are and whether they've been looked after (by not letting the caliper hang freely stressing the line)

yeah I get that. I just thought you were implying the rubber lines get eaten by dot 5 thingie. nvm I know lol :D
 

Enuo

Glorified Electrician
what so you can just drop dot 5.1 in then
Yup, in my last car at some points I had 3, 4 and 5.1 in it, all at the same time. Only thing you need to watch out for is mixing DOT fluid with the old (glycol based?) stuff, as that WILL destroy the seals, as my clutch slave cylinder discovered...
 

SirChris

Educated Bodger
i know now lol! sorry sounded bad. No i had no idea so I tried putting two and two together... bad idea huh?
 
OP
OP
h701micra
No, as long as the mean velocity of the gas remains constant, changing the diameter of the pipe will not change the pressure, you will only chang the mass/volumetric flow rate. Pressure in a continuous flow situation is only affected by velocity, temperature and enthalpy changes (eg burning fuel)
Edit: I think, been a while since I did thermodynamics and fluids at uni
To which the gas velocity is never constant due to changing rpm? Were looking at a variable gas flow/velocity rate.
Higher gas velocity means higher back pressure. Put through a larger pipe is reduced
 

Enuo

Glorified Electrician
To which the gas velocity is never constant due to changing rpm? Were looking at a variable gas flow/velocity rate.
Higher gas velocity means higher back pressure. Put through a larger pipe is reduced
Faster moving gases exert less pressure though, thats how aeroplane wings work, and how venturis work. If anything, bigger exhaust pipes will lose you power at the bottom end as the slower moving gases exert a higher pressure in the system, leading ti back pressure. Small diameters limits flow rate at the top end, but increase flow rate quickly at low-mid end which will lead to reduced pressure i the system. However, in an exhaust syatem the pressure difference due to velocity will probably be less than 1psi, it won't make a great deal of difference. After all, exhaust gases barely exert more pressure than atmospheric anyway...
 
OP
OP
h701micra
Faster moving gases exert less pressure though, thats how aeroplane wings work, and how venturis work. If anything, bigger exhaust pipes will lose you power at the bottom end as the slower moving gases exert a higher pressure in the system, leading ti back pressure. Small diameters limits flow rate at the top end, but increase flow rate quickly at low-mid end which will lead to reduced pressure i the system. However, in an exhaust syatem the pressure difference due to velocity will probably be less than 1psi, it won't make a great deal of difference. After all, exhaust gases barely exert more pressure than atmospheric anyway...
Diving off topic slightly. So a vacuum diaphragm... needs slow moving gas to create the pressure to move the diaphragm? Not the fast moving gas it gets in reality... yet if we increase its pipe diameter we lose its functionality due to a pressure drop. Found that out by accident :oops:
Same with the charge from a turbo a smaller pipe will build pressure higher faster than a larger pipe as there's more space to fill before creating any pressure (the lag we experience) or boost in that case
Or air flowing on a road increases in speed and pressure as it goes through a tunnel due to a negative pressure the other side.
Airplanes are another story entirely :p

Right or wrong.... I'd say we've gone a bit deep into it for novice mechanics looking for a budget horsey :p
 

frank

Club Member
However, in an exhaust syatem the pressure difference due to velocity will probably be less than 1psi, it won't make a great deal of difference. After all, exhaust gases barely exert more pressure than atmospheric anyway...
i welded a fitting into the downpipe (post turbo) and recorded 3 or 4 psi :)

P7080167.JPG




 

Enuo

Glorified Electrician
A vacuum is an absence of gas tho eh, the gas hitting the diaphragm hits it from the other side to move it. And theres a massive difference in the amount of pressure you get from a pump (e.g turbo) and from the result of how fast the gas is moving.

My aquarium air pump puts out 2psi, it's not alot. I'm glad I was in the right sort of ball park though :)
 
Top