Most efficient route to reach 350HP in an e30?

[Blackdave458]

Hello Everyone, I am dying to just talk with people about my e30 goals. I have only been using a search function on google and on here to guide me on my E30 goals but i have decided to finally take part in the forums.

Basically I want my 325is to reach 350HP and I've been up until 4am watching videos on youtube in deciding what is the most cost efficient route in attaining this while considering maintenance costs and reliability to the platform I'll be building on.

So my question is, Which route is the best to achieve 350hp in an e30 that won't involve spending way too much and keep the build as reliable as possible (meaning, least amount of maintenance, breaking and fixing constantly)

So far my options have been reduced to:

1.) Supercharged/Turbo M50 swap (or m52?)

2.) M60 v8 Swap

3.) Turbo S52 swap ( this one seeming to be the most expensive and risky?)


I can't seem to be attracted to putting an LS1 into this car but if that is the cheapest and most reliable way to get to 350hp i might consider it...

Your time is appreciated and i apologize if i didn't read something i should have. I definitely used the search function beforehand and didn't see this exact question anywhere. Thank you.

[moatilliatta]

Sub 100k S54, Rod bearing, vanos bolts and seals, epic headers, 3.5 exhaust, epic tune.

Done.

:)

This is at least my next iteration after current s50 goes or I get all the other work done. But a reliable 350 WHP is the goal.

[ForcedFirebird]

Cheapest and easiest route is turbo the m20. They are dead reliable, cheap, and easy to work on. I've done countless 300+whp m20's and it only takes 1bar on a 60-ish mm turbo.

[zwill23]

Glad to see a turbo m20 up vote, only as reliable as your setup

[jbontke]

Cheapest and easiest route is turbo the m20. They are dead reliable, cheap, and easy to work on. I've done countless 300+whp m20's and it only takes 1bar on a 60-ish mm turbo.

I assume you are not talking eta m20s?

[Staszek]

Cheapest, turbo M20, fast but definitely not a smooth power delivery.

More reliable still cheaper just not as much as the M20 is an S50/2 Turbo, power delivery is better but still laggy.

More expensive and complex but the most natural feel go S54 with Rodbearings and Vanos rebuild and a few other mods you will touch 350 but it will be very reliable linear power, just less TQ but the E30 is so light you dont notice.

[digger]

did you s54 guys miss the without spending too much note? metal snail on current engine for sure

[DrJosh]

Turbo M20 for cheap power. LS for usable power

[ForcedFirebird]

I assume you are not talking eta m20s?

In the OP it was stated "my 325iS", made a strong guess it's a b25. ;)

[Andy348]

Cheap, fast, reliable. Pick two.

S54 will cost more, but IMO is your best bet. Once set up correctly, it will be reliable, provide linear power, and won't require so much tinkering.

My experience with turbos = constant fiddling around with it to get it right.

[ZeKahr]

Domesticate 350 wild horses and hook em up to your E30. You now have 350 hp at all times :)

[R3Z3N]

Currently the S54 is cost prohibitive if you are unable to fabricate your own subframe. There are ~2 known subframe fabricators left, both in the EU.

Cheapest to 350HP is NOT an S54, as you will be quite under that for ~$15-25k easy. Generally you will have an old engine already with ever dwindling ECU support, especially as M3 forum is gone. My github upload helped, but the collaborators are not collaborating and fixing anything.

You want 350HP cheap? Turbo, and rebuild often. You want 350HP reliable? LS swap or similar. You want 350HP that will dwindle quickly? S54 swap.

I had an S54 swap. While fun, the torque was not there. I should have gone with my gut instinct after driving my buddies S54 Z3M, and realized my healthy S52 is just barely slower. But I drank the koolaid that the S54 is shits and giggles. It's not. IMO its a VERY over rated engine. Over rated enough that BMW also never used it in racing. Fun yes, but not at the premium they go for IMO, ESPECIALLY as the E30 needs so much strengthening for that kind of power, and the E30 IMO is already a pig of a car, it really is damn heavy for how small it is. Not to mention that the weight distribution with an S54 is already Audi bad..

[varg]

Turbo M20 is definitely cheapest/easiest. Typical costs just off the top of my head...
.
Turbo $700+
Header $500+ (honestly just shell out and get a really nice thick one made by a pro fabricator, even the decent production ones crack or come with warped flanges)
Injectors $300+
Megasquirt $500+
Wideband gauge/controller/sensor $200+
Fuel pump $150+ (for one that won't just crap out on you)
Wasted spark conversion $150+
Head studs $200+
Clutch $400+ (do NOT buy cheapo clutches)
Intercooler $100+
Piping/couplers $50+
BOV $50+
External wastegate $250+ (if you choose to go that route)
Oil pan modification and oil drain and feed line $150+ (unless you can TIG the aluminum yourself)
Motor mounts $dick (just buy hockey pucks and drill and cut them, the poly aftermarket mounts are a waste of money at $60+ for a chunk of poly with a hole straight through it, a stud and a washer)
Exhaust $???? I've never paid to have one made, I just booger it together with parts from columbia river mandrel bends with my $150 welder. Honestly it's worth just buying a cheap harbor freight welder to do this because the labor will cost twice the cheap welder
Tuning $300+ (if you teach yourself, be careful. I've cleaned up messes after quite a few people who underestimated the task)
Incidentals $good luck
Labor $toomuch

You aren't getting out of it for under that unless you have the stuff laying around or cut corners. Ebay turbos don't last, used turbos always wind up needing a rebuild eventually which is $200+ done right with a balance and holsets aren't $150 like they were when I got into cheap turbo cars, walbro fuel pumps are a stupid thing to buy at this point because knockoffs are everywhere and walbro does not warranty the genuine product... Double the cost above if you can't do the work yourself and fabricate.

[ZeKahr]

Fun yes, but not at the premium they go for IMO, ESPECIALLY as the E30 needs so much strengthening for that kind of power, and the E30 IMO is already a pig of a car, it really is damn heavy for how small it is. Not to mention that the weight distribution with an S54 is already Audi bad..

E30s were designed with the consideration that the driver may use the car to cruise autobahns at speeds of 90-140 MPH smoothly. When you design a car with such a criteria, you have no choice but to make it heavier (relative to other cars of its size) in order for it to be stable at such high speeds

That said, I was shocked one day at how light the E30 is when I accidentally bumped my pelvis into the back of my parked 325 (and this is a 6 cylinder mind you) and the car moved forward considerably without me applying much force. Out of curiosity I did the same pelvis bump test on the back of my parked E46 325i and it wouldn’t budge. The E46 is about 500 lbs heavier.

One time I had to get my E30 towed. The tow truck driver was surprised when I told him my car only weighs ~2800 lbs; he said “but its a steel chassis!”

[R3Z3N]

E30 with m20 reaching 140 lol. Sent from my SM-G973U using Tapatalk