E34 2.5 tds - help me build a frankenstein

[krazy8]

Greetings bimmer fans! I'm trying to figure out a way to build my future E34 2.5 tds.
So I've been searching information for weeks and still there is a lot to read but im close to getting insane
First of all I have always been a fan of this model since my dad had 3 of those - it was the first car that i've been riding with 200 km/h

I am 20 years old with big lust to build myself such a machine, so I've got many questions - i want to build something both for my daily and still aggressive car.
People are telling me that tds has big problems with cracking cylinder head, but with proper maintenance i believe i can keep it working with no problems.
Even if it cracks one - a good one costs like 40-50 euro here.

LET ME NOTE that: I am no car specialist - I just read stuff in my interest. I have little practice with cars although my dad is a car mechanic

Here is a list of the mods i think to do:
-Straight pipe with no catalyst
-Mechanical pump from 524td (is it better than the electric??)
-Turbo with manifold from 524td (they said it is bigger, but didn't find info, is it really bigger and what would be optimal pressure for it?)
-Isolated EGR (does it matter if its removed or isolated? if its removed what do i put there?)
-And finally here comes chip tuning - Does it need to be the final step?

There are still things that i'm thinking and not sure how to increase performance of the engine. I haven't included mods like new intercooler, radiator ... etc - things that are main to keep the engine cold and not get it overheated. I don't mind smoke, so it doesn't matter if it smokes A LOT. I'm looking for something like 200hp and keeping it stable not murdering the engine completely, I want it as a daily.

Do i need to have an lsd and what do those numbers matter for differential? for example 2.10

Im just a new car enthusiast looking for his dream car - any information about E34 and tds will be 100% helpful.
Currently driving a ford fiesta... why are people having fun annoying me about the ford xD I don't wanna die with it.

[moroza]

Hello and welcome!

Regarding your car, you'll be happier if you follow the rule of Maintenance Before Modification. Fix what's broken, take care of what's neglected, before messing with what works.

That means:
1. All five fluids changed on time (engine oil 5000km or 6 months if regular, 10-20000+km or yearly if synthetic, auto trans oil 50000km, manual trans oil ~100000km, diff oil ~100000km, coolant every three years, brake fluid every three years), and all four or five filters (engine oil, engine intake, cabin air, fuel filter, trans filter if automatic).
2. Nothing rubber that's important is cracked (brake hoses, fuel hoses, tires, wipers).
3. Nothing in the suspension loose, except a little steering slop (all E34 except maybe the iX have some).
4. Nothing leaking.
5. No electrical problems.
6. No serious problems elsewhere.

Then, and only then, should you talk about straight pipes and LSD and everything else. Doing all this will also give you the practical experience to be able to modify your car, rather than just read about it.

Is yours an auto or manual? If auto, changing that should happen before increasing any power.

That said, I'll answer some of your questions:
1. IMO, straight pipes on a petrol BMW sound like garbage. Don't delete the catalytic converter. If you're turning up a turbodiesel, definitely use bigger pipes; even if it gains no more power, it'll help lower exhaust gas temperature (EGT). IMO, the best-sounding turbodiesel sixes are Mercedes OM606, which use a single 65.5mm pipe from the turbo to the muffler, only one big resonator (combined with the cat).
2. I have no experience with BMW diesels, some with other diesels (VW, Mercedes, various Japanese, various farm and construction equipment). In general, a mechanical injection pump will run a little less smoothly than an electronic one. It'll be a lot more reliable, and if tuned right will get as good economy as an electronic injection pump (not to be confused with a common-rail system like the M57, which must be electronic and has inherent efficiency advantages).
4. Again, no specific experience with the M51, but EGR delete is usually a good thing on diesels, turbo especially.
5. There will be no chip if you convert to a mechanical pump. There will be nothing to put the chip into.
6. To tune a turbodiesel, first and foremost you need a pyrometer (EGT gauge) and a boost gauge. Then, feed it more colder air. Then you can add and adjust fuel until one of three limits is reached: there's smoke, EGT are too high, or something breaks because it can't handle the thermal or the mechanical stresses. After gauges, bigger exhaust and better intercooler are where to start, in general, then it depends on the specific case.
7. You don't need an LSD.
8. The diff number is a ratio: how many turns of the driveshaft per turn of the axles. The effective ratio depends on the transmission. E34 525tds uses a 2.65.

You might not mind smoke, but mostly everyone else does (including me). The whole "rolling coal" thing is disgusting and gives car culture a bad name. It's also extremely idiotic - that black stuff is fuel that wasn't burned and didn't make any power, it's just been wasted and turned into something useless and harmful. In western Europe, they're already starting to make combustion engines in cars difficult to own, especially diesels. Don't give them any more reasons.

[krazy8]

Thanks for reply! Yeah i found out today that if i use mechanical pump i can't chip the car but i heard that you can move something and make it eat more fuel, creating more power. I have in mind all the first stuff you listed because i want my car to last not just drive it 6 months and let it become trash. I will never buy an auto car , always manual gearbox. Still can't find out if that 2.4td turbo is bigger and will it be better than the TDS one.. i mean is it worth the effort or just boost the tds one. For the smoke... yeah its bad but that's the only way to keep drivers away from my taillights because they stick like centimeters behind my bumper and i'm scared to press the brake not because they will be in crime but they will smash my car Anyway i should put a towbar just to make them feel it better

[moroza]

Towbar is an excellent idea. I don't get tailgated often when I drive my truck - a 1981 4x4 Hilux with a tow hitch, mounted to a ~70kg plate steel bumper, basically a triangulated battering ram.

Yes, there are a lot of things that can be adjusted on a Bosch VE pump to make more power, but those things happen after doing and learning a lot of other things.

[roundhouse]

Hi. It's not the best idea to make a POWERFUL M51, because cylinder head is a weak thing on these engines. M21 is really much stronger, and can hold up to 500+ ps with big turbo. For M51 optimal performance is about 170-190 ps, and you can reach it via firmware edition. There's experiments with geometry corrected turbos on m51, but too many moves have do be done, is it worth it?

First, you'll better buy a car with inductive pump, not resistive. Inductive ecu is much faster, has more adjustable parameters, and can be tuned much easily, than resistive one. And resistive layer on the pump head often is worn out, what leads to instable idle and many side effects.

Easiest way to add M51 some performance is to rise injection ammount, it can be done with moving pump head or via dis/inpa. But after that the engine will be smoking, and idle will be not smooth (at least). So it's better to chip-tune the ecu.

Resuming: for optimal and safe m51 performance you don't need much upgrades on hardware level: big turbo, exhaust, mech pump, etc. It's a bimmer, it's good enough from factory You'll better give it a good service (clean oil separator under the valve head, check if the timing chains are not weakened, clean the pump, check all gaskets, clean and set up injectors, etc) - and slightly tune then. The one thing on M51 hw can be tuned, as for me: it's an intercooler. In hot weather performance often is noticeably weakened, I think bigger cooler will do the job better.

[krazy8]

Hi! Yeah m51 got its notorious fame with that cylinder head everywhere lol . 170-190hp is just what i am looking for. Fast and easy hp with not much mods because i am unskilled and unable financially to do more. For m21 i think i won't be going that direction. Its a path for people with more experience in those things. I have found an unoriginal manual written in my language just for the tds and there you can find information about the weakened timing chain so its a no problem.

Thank you for information, i appreciate it.
Looks like i will do only those stuff on the tds:
-straight pipe
-moving pump head
-cooling system upgrades
-chip tuning

I am not sure- should i boost the turbo more? They say it will not be a problem from the stock 1.1 bar to 1.3-1.4bar... Will the engine withstand the pressure?? And also i have seen people put a gauge for their exhaust fume temperatures - i don't remember correctly but around 600 celsius they said you can break the head. Is that true?

- - - Updated - - -

Btw just let me mention that here in my country there are lots of parts, good parts selling out for like 80-100bgn (40-50 euro) and i'm so envious of the fact that i can't buy them all xD. For example yesterday there was a working gearbox for 40euro... are the e34 parts that cheap in your countries?

[krazy8]

Something i forgot - i plan to dig up the inside of the factory air filter box, should i do it?

[roundhouse]

-straight pipe
-moving pump head
-cooling system upgrades
-chip tuning

I am not sure- should i boost the turbo more? They say it will not be a problem from the stock 1.1 bar to 1.3-1.4bar... Will the engine withstand the pressure?? And also i have seen people put a gauge for their exhaust fume temperatures - i don't remember correctly but around 600 celsius they said you can break the head. Is that true?

- - - Updated - - -

Btw just let me mention that here in my country there are lots of parts, good parts selling out for like 80-100bgn (40-50 euro) and i'm so envious of the fact that i can't buy them all xD. For example yesterday there was a working gearbox for 40euro... are the e34 parts that cheap in your countries?

Moving pump head on the inductive system can be a pain - it's too sensitive, you'll have to catch several microns (literally) to properly adjust injection amount. It's much easier to do it via dis/inpa settings.

Chip-tuning is better done with test run on every adjustment, because too much parameters are depending on the hw, it's wear grade. After proper chip-tune you won't need any additional adjustmens in dis/inpa. And good tuned m51 won't be a rolling coal within 200hp (it's important to properly tune smoke maps of the ecu).

Yes, adding some pressure, up to 1,3-1,4 bar will be ok, but it will require chip tuning too: stock firmware will cut off injection amount on higher turbine pressure levels.

About filter body - I don't think that you'll need something to do with that, it's big enough and performance is ok. Sooner, you'll need to do smthn with EGR/AGR (cut it off, to be more exact).

[krazy8]

Yeah egr will be removed soon asap. What are those dis/inpa settings?
And also, which one should be done first? Adding pressure to the turbo or first chipping the car?
I'm having issues in what order should all the mods be done... should the chipping be final step when everything else is set or?

[roundhouse]

Yeah egr will be removed soon asap. What are those dis/inpa settings?
And also, which one should be done first? Adding pressure to the turbo or first chipping the car?
I'm having issues in what order should all the mods be done... should the chipping be final step when everything else is set or?

1. Injection amount.

2. Chip > add pressure.

Tune the ecu first.

It's better done in last order only if you plan huge hw changes, like big turbine, other injectors, etc. For the balanced m51 tuning (up to 200 hp) it's not needed. Just tune it well, with live testing.

[krazy8]

And still should I keep the turbo from the tds or change it? Will it be able to make 200hp..i mean I don't want to buy turbos every month😂 I believe it will be a good enough daily ride and aggressive dirty diesel. Except for boost controller do I need something else to increase pressure? Btw thanks for all this info, you're helping me a lot guys.