New Manifold makes +18 BHP on stock 325i with dyno

[chip-3door]

You honestly do think the change of CC is a big deal dont you?

I take it that you have NEVER rebuilt any engines for more performance at any point during your life and learnt about what makes them tick?

[jonb]

i was beginning to think i was the only one on here who's ever actually played with engines much, LOL

chip

it sounds like your used to playing with other things on a regular aswell.

its sounds like you know your stuff. but youve belittled many people on here.

nots being funny, but many people have much much more important things to be doing than messing around with A series engines, and minis in general. like getting getting there end away for instance.

[Simon13]

every post u make is charlie big spuds

I know where i am going with my M20 and what i have learn't along the way. Just saying my 2p from what i know.

but clearly u know more than i do.

I'm coming from a common sense point of view

As u know what makes some engines tick go try these and see how far u get. Jhonno, why are u not even bothering with this engine? strange how u see it's easier than people say to get the ponies and, u have bought an E36 M3 lump.

The change of cc does make a difference. Whats your knowlegde on M20's? Cosworth engines are totally different.

[syh]

So what's the differnece between the 12v and the later 24v which is kicking out closer to 200bhp????

[Jhonno]

i was beginning to think i was the only one on here who's ever actually played with engines much, LOL

chip

it sounds like your used to playing with other things on a regular aswell.

its sounds like you know your stuff. but youve belittled many people on here.

nots being funny, but many people have much much more important things to be doing than messing around with A series engines, and minis in general. like getting getting there end away for instance.

jon, i wouldnt take anything chip says to heart as with anyone else on an internet forum. he appears to enjoy baiting ppl and reeling them in

Merry Christmas btw

[Jhonno]

every post u make is charlie big spuds

I know where i am going with my M20 and what i have learn't along the way. Just saying my 2p from what i know.

but clearly u know more than i do.

I'm coming from a common sense point of view

As u know what makes some engines tick go try these and see how far u get. Jhonno, why are u not even bothering with this engine? strange how u see it's easier than people say to get the ponies and, u have bought an E36 M3 lump.

The change of cc does make a difference. Whats your knowlegde on M20's? Cosworth engines are totally different.

dude, the m3 lump is in a different league to the m20 is why im going with it, it makes 286bhp out of the box with potential for more, its more modern, fuel efficient etc

i was gonna go with an m20 until i saw the m3 lump..

i still like the idea of buying a cheap 325i at some point and having a play with it see what can be done but im a student atm so can only afford 1 project at a time

you are right the cc's do make a difference but its not as big as ppl seem to think sure its only worth about an actual 3% or summat per 0.1 litre increase

[Davenotouring]

So it'd be just over a 10bhp increase for a basic capacity increase?

This sounds about right I guess, if everything else is kept standard. But I guess while the engine is apart, further mods would be made, which would make a greater percentage increase due to the larger capacity. (Not loads though)

It's really quite hard to make a big increase on an NA engine without spending alot and taking a fair bit of time. Except for the simple 'breathing' mods like the manifold and full exhaust, and intake mods. Possibly a chip too, but I don't know enough about this to comment.

[M5pilot]

From what Ive seen is that no one has really attempted to make a beasty 2.5 before. Most people take apart the engine in the quest and in that process end up going 2.7 because it costs hardly any more.

You make a 2.5 using nice light pistons, a compressions ratio of 10.2:1, use the 284/272 cam and all the other stuff Ive said and you wont be far off the BHP of a 2.7 with the same spec.

The difference will lie in the torque. The 2.7 will have a much better torque spread and alot more of it aswell.

Simon, Alpina cams are 268/268 and I that cam is not in the 2.7 Alpina I brang to Aces anymore.

[M5pilot]

Just to add,

I spoke to bexleys about 2 years ago about different routes for the M20.

They said that a 2.5 would be very very near the power of a 2.7 if the same things were done to both.

The 2.7 would just be more versatile.

I'm just wondering what the result would be if I got my head to the same spec as Player6's engine, use manifold, use 284 cam, use MAF.........set compression to bloody high.

If you made the 2.5 a 2.7 but kept the standard head, cam and compression ratio how much powerful would it be than a stock 325i?

[Karan]

all this talk of a few horses is really a waste of time......put it on the road and check the versatility of the delivery in the corners on a track/road and thats what matters

for example-----in comparing my 2.7 to an e30 m3,,,,, my car is quicker in the dry in a straight... however cos of the bang style delivery and torque rush at 4k.... keeping up with a hard driven m3 in the rain is very hard and afte each gear change u have to take it easy on the throttle whereas the m3 driver just floors it with no hesitation!

in the dry however including in the twisties the 2.7 jumps out of corners better than the m3 and if driven well should be just as good midcorner...


just a thought.......

[E30Adam]

Just to add my 2 pence worth here.

As many of you know my engine is stroked to 2.8 litres and has a lot of mods and I'm only hitting 204bhp with it and about the same amount of torque. Mods included are Schrick 284/272 cam, BBTB, MAF conversion with shielded pipercross filter, full Scorpion exhaust system and Unichip with remap.

Now this says one of 2 things:
a) My car hasn't been mapped to it's full potential or;
b) Getting 200bhp out of a 325 with similar mods is not an easy task

I totally echo what Karan says here, there's no point batting power figures back and forth, what matters is how the car drives on the road. Now whilst my power figures don't look particularly impressive on paper (or screen), those who have been in my car or driven it will tell you a different story. I have even surprised myself with some of the cars I've managed to see off. There is torque all the way through the rev range and the car just takes off whenever you put your foot down.

I would like to see a package that would offer 200bhp for the 325 but if it's a case of relatively simple bolt on type mods then why has no-one done it in the previous 14 odd years of the E30's production??

The proof is in the pudding as they say.

[bigkev]

you hit the nail on the head there adam its all about the torque and power delivery horsepower is great down at the pub but torque is what gets you from one corner to the next why do you think the golf GTI 8valves are legendary they dont make huge horsepower but they have great midrange grunt (for there size ) and throttle response

[tomstickland]

There's real BHP and there's claimed BHP - real BHP is much harder to achieve. For example, it took twin 40s, cam, headwork, larger valves and exhaust system to get 165BHP out my Vauxhall 2.0 8v engine. A lot more work than a K&N filter, chip and big bore throttle body. However, I knew it was a real 165BHP from a combination of calibrated speedo + top speed, 1/4 mile times, 0-60 times etc. The engine lasted about 5 months of daily 7700rpm use before I took it apart and found that it was busy self destrcting itself.

Anyway, my point about the 200BHP from a 2.5 is that the engine is probably best left producing a reliable 170BHP rather than 12 months of near 200BHP and then a rebuild.

Tuning is fun and all that, but race and rally engines are tuned for a short expected life span, so for a road engine I'd stick within 10-15% of the factory power output.

[bigkev]

i hate to be a killjoy but looking at those dyno curves all that has happened is that you have taken a chunk from thelow end and stuck it on the top end it only starts making good power from 3800rpm and looks terrible below that and thats exactly where you want it around town or when you dont want be a racing driver

[M5pilot]

Remember, that dyno comparison is WITHOUT any mapping to suit.

Once mapped with the new manifold you should regain quite alot of the bottom end loss.

I am going to mention this yet again -

Nadz 325i with 190bhp delivers better low down torque than any normal 325i. More power, more torque through out the whole rev range.

These are NOT claimed figures they are fact.

A 200+ bhp 2.5 doesnt have to be one that has alot less torque low end than standard. Its all down to the choice of cam and intake you use and how well the car is mapped.

Hartge have been getting a claimed 190bhp from the H26 for over 10 years now and when reviewed it was said to have no less torque than a stock 325i but the top end was much better.

As Simon13 says - the 325i cam is flat as they can get, any cam upgrade will give better power throughout the rev range once mapping is done.

[bigkev]

how much is a remap generally

[Moofles]

i think we need someone to just make this 200hp 2.5 and then show some dyno plots with comparative ones from a standard 2.5 and a 2.7...

[bigkev]

gentlemen please place your bets!!!!!!!!!

[Karan]

i think all these creations need to be put on track and raced

[Jhonno]

i think all these creations need to be put on track and raced

definately

[MONSPORT42]

Merry Christams all. Just returned from a party and picked up this thread. It's certainly got everyone's juices flowing! As 2.7 owner I've picked up on the extra horses debate. I think it's the difference between adding an extra 200cc by changing to the 525e crank and doing a complete 2.7 conversion. The longer throw crank changes the characteristics of the engine to a lower revving, higher torque lump without necessarily getting any extra bhp just better torque lower down the rev range. A proper conversion involves modifications to conrods, pistons and compression and a remap which should take you to just over 190bhp. It will still be a comparatively slow revving engine albeit with lots of low down grunt which will really throw you down the road from standstill.
So for me it's not just about adding cc s. But once you have them you have a great platform for opening up the full potential of the M20 of adding a great deal more power with conventional tuning mods - more air in quicker, longer combustion time and exhaust out quicker and of course optimum mapping.

[chip-3door]

you hit the nail on the head there adam its all about the torque and power delivery horsepower is great down at the pub but torque is what gets you from one corner to the next why do you think the golf GTI 8valves are legendary they dont make huge horsepower but they have great midrange grunt (for there size ) and throttle response

Horsepower is what gets you around quickly, not torque.

The important thing is torque @ wheels, and high BHP not high torque is where its at for getting torque @wheels (subject to correct gearing)

[chip-3door]

From what Ive seen is that no one has really attempted to make a beasty 2.5 before. Most people take apart the engine in the quest and in that process end up going 2.7 because it costs hardly any more.

You make a 2.5 using nice light pistons, a compressions ratio of 10.2:1, use the 284/272 cam and all the other stuff Ive said and you wont be far off the BHP of a 2.7 with the same spec.

The difference will lie in the torque. The 2.7 will have a much better torque spread and alot more of it aswell.

Yep, spot on, its the other changes that make the power, not the capacity increase, all the capacity increase does is drag everything down the rev range a little which makes it a nicer daily driver.

[chip-3door]

i hate to be a killjoy but looking at those dyno curves all that has happened is that you have taken a chunk from thelow end and stuck it on the top end it only starts making good power from 3800rpm and looks terrible below that and thats exactly where you want it around town or when you dont want be a racing driver

Thats what most N/A tuning is all about, head mods and cams will do similar, add up the top but take away lower down.

Its all a big compromise, you cant have it all at once.

[M5pilot]

Another thing Ive seen is that most guys wil go the 2.7 route and not bother doing anything to the head which sounds totally mad to me.

Quite clearly most of the very high powered 2.7's all have extensive work done to the head.

Another thing I wanted to add.

Chrome bumoper 325i's have 9.7:1 CR. for anyone thats ever driven one they will always come back and say how powerful they feel and on every dyno day they have shown to be atleast 5-7 bhp stronger. This is the engine I'd like to play with to start with as you've almost got the higher compression ratio of most of the 2.7's.
Then add the other bits and I wonder where it would take you! I'm sure some skimming of the head would get you the 10:1 CR required.

Any early Sport drivers want 200bhp?

[H35-IAN]

id love a 200bhp m tech 1

[M5pilot]

Ian,

you should get that H26 dynoed for us. Would be interesting to see what that puts out. Has it got a 6 branch?

[M5pilot]

Another Quick Scenario:

PLayer6's car currently puts down 250bhp.

Now lets take away the 2.7 bottom end and replace it with the exact same spec 2.5 with compression ratio the same etc etc.

Do you think it would lose 50bhp+?

[Jhonno]

No!!

[Jimbob]

2.8 bottom end?

[m-dtech]

if you can get 200hp out of a 2.5 for say Ԛ£3k it might tempt me to get one in january

let us know! whack a chip, cams, whatever on this other car that got 185hp...

Ԛ£3k would get you a 3.5 conversion easily !

[Moofles]

if you can get 200hp out of a 2.5 for say Ԛ£3k it might tempt me to get one in january

let us know! whack a chip, cams, whatever on this other car that got 185hp...

Ԛ£3k would get you a 3.5 conversion easily !

if you mean m30......nooooo

no offfence to people who have done it, it's a good budget conversions, but i just can't stand the wastefulness of power (hp & tq) compared to the displacement...

[Moofles]

Another Quick Scenario:

PLayer6's car currently puts down 250bhp.

Now lets take away the 2.7 bottom end and replace it with the exact same spec 2.5 with compression ratio the same etc etc.

Do you think it would lose 50bhp+?

i guess i was one that was doubting, so i should respond...

i didn't say it wasn't possible to get 200hp out of a 2.5, but in this thread it appeared a 200hp 2.5 could be made for pennies (well, under Ԛ£3k i suggested). There's no way anyone can claim scot's engine was cheap, not by a LONG way. what did it cost, Ԛ£15k?

the 2.8 part of the build probably doesn't account for a lot of that cost, i.e. a 2.5 would cost near-enough the same to have the same mods the 2.8 has.

I do realise that he had it built (rather than DIY'd), though...which would reduce the cost....but i'm not sure it would reduce it quite as much as is needed to get under Ԛ£3k!

[chip-3door]

The problem with these engines as i see it is the lack of CR for any real power.

Skimming the head is going to yield gains, but unfortunately having to open the head out around the valves to unshroud them for better flow will drop the CR again.

So you need to either deck the block, or fit some higher CR pistons, or up the CR with a 2.7 conversion.

Anyone ever actually tried decking the block to see what CR you can get to on the stnadard pistons?

[Jordan]

decking the head/block quickly ruins the cam timing. The belt will not line up on the cam gear at TDC. This isn't the place to look for compression.

Either way there is very little to be gained % wise by bumping up compression. In fact the only thing you stand to gain for sure is a detonation problem.