What are the best engine mods to increase power in E30 325i

[M5pilot]

That was done over an almost 100 mile round trip to Ant's place and back.

Evo-S

[Andyboy]

Hmmm. 18 bhp from a manifold on a standard engine where the stock exhaust ports are the same size as a 320i. That I MUST see! Not a hope in hell. The old Alpina tubular manifold made by Janspeed added about 2-3 bhp to a C2 2.7 (dyno proven by someone with nothing to gain) so where an extra 14 - 15 bhp comes from is anybody's guess. I personally don't believe it.
That 2-3 bhp came on an engine with a ported head, an extra 200cc and a spikier cam too. I would be amazed if this manifold on a standard 325i gave more than 5 bhp.

I've said it before and will say it again - for £2000+ you need an M54 3 litre with loom and ECU. 230 bhp standard before you start playing with it. 230 bhp, 30+ mpg, turnkey reliability and plenty of torque. Physically it's no harder to fit than an old M50.

[Jhonno]

forgetting fly by wire throttle tho surely andy?

[oakey]

If you put any manifold on a bog standard 325i and remapped it you would get a good gain ofcourse. but is this not down to the better mapping?

[Simon13]

you won't because the rest of the engine is standard. yes you can get the gasses out quicker, but the intake side of things is still standard

[ShakeyC]

Being a newbie here reading many posts made me more confused than answered genuine questions? i like to know what mods work best but nobody shows any proof, facts or figures, trust me i searched hard! its all claims from anybody whats to say if i pee in my tank will make my car go a 1/4 mile in 15 secs and sell my pee for £289.14 and trust me there is lots people who would buy on based claims, luky for you im too honest to rip peeps off
Half people say exhuasts wont work but then other half say they do i like to see before and after graphs, outright figures do not tell the whole story peak gains are meaningless where is the peak? how wide is the torque spread? Same with cams what affect does more duration or more lift have? granted power band moves up but does it spread wider or narrows where you onlt get power for 2000rpmjust before rev limiter?

[reggid]

the problem lies in that people think the power from the BTB comes from only the reduced restriction! It is properly tuned to work different to the standard system so the power band changes meaning you gain some and lose a little, this is the reason why many don't work becasue all they are good for is reducing the restricition. There is a before and after graph from M5 pilot and if you search you'll find mine aswell on a non stock car.

Ulitimately both a cam and extractors do work well together so you really need both anyway so which one makes the most on a stock car is not that important just do both and you won't be disappointed.

[ShakeyC]

im such a div had pictures disabled in my browser

[M5pilot]

The results from reggid's car (hope you don't mind me posting these)



Notice - same type of dyno:



That's two tests which show the manifold to work to give large gains.

I can't believe people are suggesting that the first dyno results are faked or incorrect. It is so easy for people to go and do a before and after test. It would be a bit stupid to put your reputation at stake.

Evo-S

[Andyboy]

Nobody is saying (well, not I) that the results are faked. But they are surely results from a car which has had the manifold and an ECU remap -I think you mentioned that this had been the case. Not forgetting of course that a good custom remap* on a plastic bumper 325i with Motronic 1.3 gives 8-10 bhp............and remembering that unless the dyno was inside a temp controlled cell (i.e not Bexleys!) the readings taken at least an hour apart (the time it takes to swap an exhaust manifold) you could be 5+ bhp out anyway and thus not conclusive. I just don't feel that bolting a manifold to a standard unmodified 325i one afternoon is going to give 18 bhp but as a combination with a proper remap you'd get quite close. Let us not forget the dyno day when Ian's M3 powered 325i gave wildly different readings in the space of 90 minutes due entirely to the air quality in a muggy workshop.

*That's not a plug in and pray chip but something custom made on a dyno with optimised fuelling and timing. A really healthy 325i with good compressions and valve clearances with a custom chip is good for 180 solid bhp. When my old man ran AmD he used to get 15 bhp from an E34 535i/735i and once got almost 20 bhp from a 525e just by advancing the timing!

[Theo]

When my old man ran AmD he used to get 15 bhp from an E34 535i/735i

Where can I go to get these results now, do you still have contacts with AmD?

[jimcameron]

When my old man ran AmD he used to get 15 bhp from an E34 535i/735i

Where can I go to get these results now, do you still have contacts with AmD?

I'll be interested too!

[Andyboy]

No, he sold up and pissed off abroad. All finished now. But 15 bhp from a decent 3.5 isn't beyond the wit of man, any decent custom remap will achieve something similar.

[Theo]

Right, well that's on the to-do list now! A good remap with a more leary camshaft should give me some more oomph.

[Andyboy]

Right, well that's on the to-do list now! A good remap with a more leary camshaft should give me some more oomph.

Shit the bed, you want to go faster???

[Theo]

Hell yeah!!!! Might need to sort that exhaust first though

[Simon13]

Theo your mad, truly

Thing is how many are there out there who can re map properly? i know about gumball and am not interested in going there

[whiterhino]

i dont know if this is worth writing but theres a guy on here called oguz327.he took the 2.7 route and got a genuine 220bhp.thats more than an alpina.another zoner called ant did the honors of the upgrade.i cant remember the full spec but thats good power in anyones book.imagine how tail happy that car is .me personally id work with that.you could change the engine but then you remove the heart if you know what i mean.happy motorin

[ed325i]

I can stretch my budget to between £1,000 - £1,400

But £1000 - £1400 is not going to get 220bhp

[Andyboy]

I can stretch my budget to between £1,000 - £1,400

But £1000 - £1400 is not going to get 220bhp

Yes it will. £350 for a sweet running MOT failed 535i/735i (you'll weigh the shell in for £80 and sell £100 worth of morsels), £100 for a manual 530i/535i gearbox and clutch/flywheel plus the rest for a manifold, engine mounts and a suitable rad and prop. Play your cards right and you'll have enough change for a remap.

[M5pilot]

Andy,

that test was done without a remap.

Live remapping (the real version) needs an eddie current dyno for a start. Emulators are also required. AMD did it this way, Bexleys do it like this and I shall also be doing it. There is premium to pay though as it's easily half a days work.

Just some points - Ian Haynes's car suffers massive heat soak due to the open air filter in a very cramped engine bay with an engine which generates alot of heat.
You should see Bexleys new Dastek fan. Creates a storm inside that workshop now and it gets very very cold! They used to have problems mapping M20's as they do like to get hot. With the new fan and extraction system they can map without having to take breaks because of heat issues. I think I might buy a fan like that!

OK.... got hotel and eurotunnel to book!

[reggid]

Nobody is saying (well, not I) that the results are faked. But they are surely results from a car which has had the manifold and an ECU remap -I think you mentioned that this had been the case. Not forgetting of course that a good custom remap* on a plastic bumper 325i with Motronic 1.3 gives 8-10 bhp............and remembering that unless the dyno was inside a temp controlled cell (i.e not Bexleys!) the readings taken at least an hour apart (the time it takes to swap an exhaust manifold) you could be 5+ bhp out anyway and thus not conclusive. I just don't feel that bolting a manifold to a standard unmodified 325i one afternoon is going to give 18 bhp but as a combination with a proper remap you'd get quite close. Let us not forget the dyno day when Ian's M3 powered 325i gave wildly different readings in the space of 90 minutes due entirely to the air quality in a muggy workshop.

*That's not a plug in and pray chip but something custom made on a dyno with optimised fuelling and timing. A really healthy 325i with good compressions and valve clearances with a custom chip is good for 180 solid bhp. When my old man ran AmD he used to get 15 bhp from an E34 535i/735i and once got almost 20 bhp from a 525e just by advancing the timing!

Any properly run dyno setup should be temperature, pressure and humidity corrected (pressure is the most critical by far) and these corrections are standard on dyno dynamics shootout mode.

Was this a late 325i?
I would have assumed that the before and after showing 18hp on a stock 325i was after a remapped simply because the before run was 008 and the after was 033 which usually means there were around 25 runs between the two, but it was clarified by Sal that therer was no remapping.

It wouldn't really make sense to do a whole lot of mods (manifold, cam, head wrok etc) and not retune for them anyway, however from a cost POV you'd probably want to do all the mods and then do a final remap.

[ShakeyC]

i can only laugh at people slating dyno graphs, ofcourse where will be minor differences place to place and the same figures will never be the same how often do you drive your car in an enclosed temperature controlled barometric measured road? i cant see why a dyno operator would fiddle the numbers? often they are set up externally and installed within a given operational %. Another things fans are shit on dynos they focus air about size of a a4 paper into middle of the car and outside the a4 paper sized area the air speed is no where near as realistic as to what you really get on road speed. If you know what your looking for a dyno plot will tell alot of info and the relative gains before an after dispite time of day and weather.