200 bhp without a turbo

[Turbo_Steve]

To be honest, you're wasting your time (and money) chasing numbers.

As you're attempting NA tune without opening the block, I assume there is a budgetary consideration.

So cheap stuff is induction (ram scoop at a high pressure area at the front, tweaked inlet piping for best flow, really really good exhaust system, uprated ignition system (better plugs, larger, individual coil packs) and a piggy back ECU are the 'easy' stuff, each of which is going to cost you plenty. Coupled with some wild cams, and a very high rev limit, this will either see you with a 200bhp NA car that is horrid to drive or a rod through the block.

The unfortunate thing with NA tune is that you pretty much HAVE to open the block: to get lots of power you really need to rev, which means carefully balanced rotating mass, and to get the air in at the right speed you pretty much HAVE To port the head, as it's optimised for low end torque and driveability.

You can get bigger numbers, but compromises have to be made.
Honda typically rely on Hand finished heads, extremely light and carefully balanced rotating mass, and approace (or exceed) the magical 100bhp/litre threshold. But in doing so, they sacrifice some of the driveability: There is nothing worse than being caught in the wrong gear in a Honda: it's gutless. Or try going 4-up, or carrying something heavy: there torque figures are so small that the blistering performance is severely muted, and you can feel it.

Homda use VTEC to alter the cam profile for a specific rev range: this attempts to retain some low end torque and driveability, as well as refinement, but keeping the exhaust valves closed longer to build torque and reduce noise. Without this, the car would drone on and feel awful below the "on cam" range (usually 4000rpms and above).

Your best bet is to fit an exhaust and airfilter to start with, and see how it does.
Careful selection of oil is vital. Uprated plugs and coils will help.

This is all the cheaper stuff, though a properly designed exhaust is going to be expensive: it will need to be computer modelled by an engineer specialising in the field.

Then drive it and see if you're happy. At this point you can decide if it's worth investing in a piggy-back (probably) and cams (probably not, as they will be pricey).

A better idea would be to put the car on a diet: start removing heavy things you just don't need.

AA membership is a lot lighter than the spare wheel.
A smaller battery will save a lot of weight.
ABS...do you want it? It's pretty heavy.
Windows can be changed for plastic.
Panels can be changed for carbon fibre (try lifting the bonnet with one finger! )
Boot carpets...
Speakers....
Subwoofer...?

Removing weight will have a much bigger impact on the cars handling and point-to-point performance than an extra 50bhp.

[Scanny]

i admit i know nothing about mechanics but vaguely speaking the engine is full of bits that are finely balanced to do their job and do it with other bits doing their job at the same time. Sounds like its easier to upset it than get any gains so best left alone!
The exhaust is on the list but from where? Im after the entire thing being custom built, not just the bit that attaches behind the cat and was sat on a shelf. Would any custom supplier give me what i want or are there different ranges depending on how its built?
Ignition system is an interesting one. Recommendations?
Dieting is further down the list although i had intended exploring the idea of plastic windows and carbon bonnet. Can that be painted though? I want to keep the car looking standard. They are gorgeous as they are. Although later down the line i was going to ask advice about vents to get the heat out of the engine bay. No big EVO vents though!
As for budget, i dont mind throwing a few grand for a few decent upgrades and some performance benefit. I dont want to waste that same money on lots of bits that either dont do anything substantial or will cause repairs later on. I would rather gain 20bhp permanently than gain 70bhp for 6 months before failing. Quality takes precedence over quantity

[Scanny]

just re read your post. High revving, not interested. The 1 party trick i paricularly enjoy about the gls (assuming the v6 will be the same) is its ability at low revs. My favourite road has a tight S bend that i can take at 30mph in 5th and coming out of the bend is a slight uphill stretch which i can still gain speed on without changing down. Its not very often i go over 4000rpm. Im not building a race car. I want a car that has consistent power available at low to mid range revs and can maintain speed uphill. If i want a bit of fun all i need to do is take it to a twisty road. Not many drivers could keep up with me in my rover 214 so the v6 should lose them in no time. Drag racing doesnt interest me. Boring, no real skill involved and high revs reduce engine life

[Turbo_Steve]

LOL! You certainly have a lot of inherited wisdom!
Whilst I salute you for knowing what you want from your car, drag racing is suprisingly difficult (especially as the car gets faster) and it's generally the huge power outputs that damage engines. Although high-revving does shorten the lifespan, proper maintainance will mean that we're talking in terms of 400,000miles down to 350,000miles before an internal failure (or suchlike).
The occasional drag race is not likely to have any impact on your ownership of the car. Conversely, if you DO like the twisty, challenging stuff, then you need to be keeping an eye on your bushes, control arms, anti-roll bars etc etc and giving them regular inspections. Also, tyre selection and inspection schedules are critical.

Getting more power at low revs is definitely going to mean exhaust and as much high pressure induction as possible. At the very least feeding the factory airbox from low down on the front bumper is a must, but be EXTREMELY cautious through any water. You'll find this "positive pressure ram scoop" should add a significant amount of power in 3rd gear, as air is forced into the filter chamber rather than sucked, and your inlet manifold \ throttle body etc will tend towards positive pressure. There is a potential risk in reducing air velocity at the inlet ports, however this is extremely unlikely on a modern engine.

I doubt you're going to find off-the shelf cams that will be setup to improve low-end power, so I'd suggest you're looking at a regrind to your parameters. This means finding a good engineering firm who will do the work, and have a good understanding of regrinds and what can be achieved.

The same goes for the exhaust: you're likely to get the best results by speaking to a proper engineering company, who will listen to what you want, and be able to show you a full page of maths and a CAD picture before doing the work.

All of this is not cheap, though, but if you want it done right, its not going to be cheap.

Ignition system is the cheapest mod, but it also shows the least returns without other supporting mods.

I'd be tempted to start with the weight loss and see where that gets you, really: It'll make a bigger difference to the car than bhp.

A change to your final drive ratio might suit your driving style more (better acceleration per gear) as if you're staying below 4000rpms, the gears are terribly long!

[bradc]

The V6's love revving, I regularly take mine to 7000rpm, and that is a JDM spec car which is rated at 175hp rather than 165hp.

Remember one thing Steve, he isn't shooting for 100hp/L, he is shooting for 80hp/L which is quite a big difference and should still allow for driveability. I'm not convinced he will need to open it up either for 200hp. An ecu tune, full exhaust system including manifolds and air intake should see it there without too much hassle.

[Turbo_Steve]

I didn't think the heads would flow quickly enough to make serious bhp without revving it: that good torque was easy, but sub 5000rpms it wasn't keen to make peak power due to the cam timings + port flow.

[psbarham]

I'm not convinced he will need to open it up either for 200hp. An ecu tune, full exhaust system including manifolds and air intake should see it there without too much hassle.

havn't you read the rest of the thread? i have stated that the fueling is near as damn it spot on, and any gains will be minimal without any internal mods, the compression on the v6 is pitifully low, and tbh too low to make any use from the engine, a good head skim and porting is necessary to gain any power.
also the cam timing and lift is a bit weak so a re grind would do it the world of good.

[Scanny]

i dont know if i would call it inherited knowledge. I know how i drive, i can read the dials and i know a few technical sounding words that i can chuck into conversation without any extensive knowledge on what im talking about lol
By the sound of it i am going for exhaust, ignition, ecu and weight loss. It might not reach 200 but as you say, losing weight could make the difference. Decent suspension maintains higher speed anyway compared to standard or 'family suspension' as i call it which reduces the need for accelerating

[bradc]

I disagree PSB, my JDM spec V6 is tuned for 175hp. It runs on 91 octane with very low levels of knock, it does count them, but it isn't enough to drop the octane reading %age in EVOScan from 100%. If you put in an ECU and tuned for 98 octane you would be able to change the timing quite a bit and run a leaner AFR.

[Kenneth]

I would think the cheapest way to 200bhp (and perhaps beyond) is going to be an enigne swap.

The issue you have is that the only way to get power is to burn fuel and air, and at a decent ratio which lets you get the most out of the fuel.

This is physics, you cannot escape this fact.

The way most (i.e. honda, as expressed by steve) manufacturers do this is with dual cam profile or variable cams and then having the engine rev out. This in turn means you burn lots of fuel (if you think in volume per second).

The problem with this as explained by Steve, is that this usually comes at the expense of bottom end torque, as the exhaust has to be configured to move enough gas at high RPM to make the power.

If you wan't that power at lower RPM, you need to get more air and fuel into the cylinders. A full exhaust will help, as will tuned intake runners (longer etc) but in the end the only way to get really good bottom end torque is with either a bigger engine or a turbo or two.

Stroking the crank and all that stuff can increase the displacement, but it will be expensive. If you can get a second hand 3.5L (6G74) engine and loom, get an adaptor made up for the gearbox and do the necessary mods to mount the engine in your engine bay, then you have a much better platform to go off.


Yes, you may be able to do it with your engine, but I think for the expense you would be better off with an enigne with more displacement.

[Turbo_Steve]

!!! Hadn't thought of that! Inspired.

My only niggle is that you'd end up blowing the budget with some mods to the 6G74....just cos you can really. Or is that just my lack of self control?

[Slimshady]

STOP MESSING WITH NEWTON!!!!!

Design Engineers spend days, weeks, months calculating mechanical efficiencies – the other month I spent 8 days with 32 pages of calculations, 14 spreadsheets, F knows how many CAD models with FMEA stress calculations, just to work out if a servo motor can move at 40g. During the calculations I used a design factor of 2 (if you are an engineer you will know that this means we have double contingency in the calculations just to ensure all is to plan and we have a bit extra just in case) after this point the whole system will fail.

What I am trying to say is clever design engineers spend a lot of time getting it right for YOU – the end customer if the end customer wants to gain a bit more, that’s fine, they are digging into our contingency of the overall calculation, obviously at their risk. If however they take the phish and go down the route that they know better than the engineer then so be it, the product will anmost certainly fail.

I have eaten into a bit of Mitsubishi’s contingency and stolen back an extra 32.7BHP simply by ramming more air into the plenum on an NA V6 – How you ask – simple, a turbo charged car works by simply spinning an impeller via the exhaust to pull air into the engine, the ECU works out how much air it has and adjusts the fuel to cope, therefore why not induct a bit more from the front of the car which is moving and therefore sucking up air – simple – a non turbo charged car charged (well a bit) but...... the advantage is the V6 is the slender non fat version i.e. we are the supermodels weighing in less than 250Kg, yes ¼ of a ton lighter than the VR4, that puts a twist on the power to weight ratio i.e. if I drag raced a standard VR4 in my slightly modified V6, I would win. On the other hand the VR4 would corner a lot harder. This is what Design engineers call trade off – swap something for another.

Simple rules:
Don’t mess with design calculations
Trade of is nice but something must give (life expectancy etc)
Only steel what you can get away with – Then STOP!!! And don’t take the Jimmy
Why spend stupid money when you can buy the manufactures better model or the competitors.


Not trying to preach, just want some of you to learn before making expensive mistakes


Wise words from
Slim

[Kenneth]

Whats your 1/4 mile time Slim?

250KG lighter is quite a claim. How much does your V6 weigh, and is it a Saloon or Estate?

I haven't been able to find any evidence that a V6 (Galant vs Galant) weights 250kg Less than a VR-4. My investigations show it to be closer to 200KG (Generous rounding in favour of the V6)

I made some basic calculation which still put the VR-4 well ahead in BHP/Ton.

Of course the problem with this is it is all based on some gross estimations and does not take into account differences in torque delivery and other potential factors that affect the real life performance of the vehicles.

Every time I have seen you make the same spiel about your V6 being able to beat a VR-4 in a drag race, I also see flaws in your argument and your calculations.

I think the only way to really be convincing is to either have a proper drag race with a known VR-4 or provide a time slip.

Also, a lighter car has more cornering potential than a heavier car. With ~200kg difference in weight, I would expect a V6 with decent tyres to out corner a VR-4 if in the right hands.

[bradc]

Remember also that at 4000rpm a V6 makes 230-240nm torque, whereas a VR-4 is 370nm

[MarkSanne]

Hmm... maybe I can add something to this discussion: a little race between a saloon VR2 (the body and weight of the V6 NA = 1280kg) vs VR4 Legnum (1580kg) (so a bit more heavy compared to a VR4 Galant) and race them againt each other:

(fast forward to 1 minute 40 sec where you will hear 3x horn when we start)
http://www.youtube.com/watch?v=79iduf4qLfQ

The VR2 (manual) is on standard boost, org. downpipe but 2.5" custom dual exhaust, de-cat.
The Legnum VR4 (auto/tip) is on standard boost, PS IIda downpipe, 3" exhaust, cat in place, driven in auto mode.

As you can all see, the VR2 wins (we did it a couple of times, same result). The 300kg less weight of the VR2 makes up (but only just!) for the lesser traction at the start (you can't see it, but I can guarantee the VR2 needs a gentle right-foot the first 2 gears). So I have serious doubts the V6 NA (even tickled with 32 bhp extra so lets say very close to 200hp) would have a chance against any VR4, only reason the VR2 wins is the weight-difference but remember it has somewhere of 260Whp (dyno'd) so 60 more compared to a close to 200hp (fiddled) V6 NA.

[Throbbe]

At risk of making myself look an arse in front of more knowledgeable people, I'll try and give you a simplification.

Think of an engine as an air pump and you wont go too far wrong. Make the pump flow more air (better intake, exhaust, etc) and you'll get more power. Unfortunately, for a NA engine, most of the increases in flow come from making the pump work faster (higher rpm). Because power is a function of torque and engine speed, increasing engine speed for a given torque value will increase power.

Yes, you will get benefits from a better burn (fuelling and timing adjustments) but this is tinkering around the edges. Before anyone mentions the gains to be made on VR's, that's because the fuelling is way too rich to begin with. If the factory setup is good (as seems to be the case) on the V6 you're already well into the law of diminishing returns. Yes, you can squeeze out a few more bhp, but be VERY aware that you're in real tuner territory there. Notice how often the likes of Ben have something go awry with their demo cars? That's not because Ben is a bad tuner, far from it, it's because he's operating on the limits because he is looking purely for performance.

What you seem to be after is more power, without sacrificing driveability. As others have said, you really want more capacity, or forced induction. Both (to my mind) routes that will have a very poor return for your money.

Fortunately, you've already identified the other viable option, which is weight loss. Better acceleration and braking, and all for free. It might not be a popular view on this forum, but for driving enjoyment on public roads, good cornering and braking, as well as driver involvement, come well below power for me.

[Scanny]

the first thing i get will be suspension which will probably be shocks/springs since i still dont know what coilovers are. Based on reputation i would like konis. Next will be the exhaust, source is yet to be identified. The air induction will be standard air box with the k&n filter donated from my gls. Is it worth changing that? Then weight reduction. Can a carbon bonnet be painted? Also using logic rather than engineering, hot air rises and it will be pushed back by the denser cold air so would exit vents at the back of the bonnet help cool the engine bay?

[Turbo_Steve]

Run a large pipe from the airbox to the front of the car for improved induction and possible power benefits.

Carbon bonnet is an excellent idea: I wouldn't worry about vents too much.

[Scanny]

a lot of stuff mentioned has completely lost me but i do understand weight distribution and with a front engined FWD car the place to try and lose it is up front. Would ditching the airbags lose much weight? I wouldnt get rid just for the sake of it but if the system is heavy then it would be worth it. I dont like them anyway. You mentioned abs. Im going to look into that. 2 incidents recently involved hard braking(rabbits) and i still managed to lock up. I dont have much confidence in abs since i had to rely on cadence braking anyway . Technology cant replace the driver

[lboots]

the n/a v6 has 161 bhp as standard. The magic number i want is 200 without taking the head off and without a turbo/supercharger. How do i get it and who can do it ie any garage, a tuning garage or a mechanic who specialises in galants?

been thier tried it, serious head and cam work required, piggy back ecu or blower, 186bhp best i got