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View Full Version : how much boost on a 1990 535i


kjbboosted
05-25-2008, 09:40 PM
Hello,

I'm just wondering how much boost a old 535i can handle with forged pistons but nothing else really modified in the bottom end?
Not just to last a week but as a daily driver so reliability is a factor.

cheers

///tyron
05-25-2008, 10:18 PM
what turbo? all depends on the set up. M30's are really bullet proof engines. Theres a bunch out there that are over 600rwhp.

NOTORIOUS VR
05-26-2008, 12:42 PM
You're putting in forged pistons? What CR are the pistons?

A stock M30 is stout and with a fairly low CR even with the original cast pistons they can take a fair amount of boost.

If reliability is a concern, you'll want proper engine management with a good tune, and don't over do it with boost on pump gas. Simple as that. But that said 12-15 psi on a well sized turbo shouldn't be a problem on pump IMO.

SamE30e
05-26-2008, 03:34 PM
I've seen one boosting about 20psi with 500k on the engine, they really are bulletproof.

NOTORIOUS VR
05-26-2008, 04:18 PM
I've seen one boosting about 20psi with 500k on the engine, they really are bulletproof.

20 psi is do-able due to the CR.. but he said reliable... so to run 20 psi reliable he'll need a good tune... Which in turn costs more money.

kjbboosted
05-26-2008, 07:37 PM
Im looking to have it set at 14-16 psi with a professional tune. Im not sure of the CR but it will be machined and balanced and blueprinted with new cam gears ect.
So in your opinions this should last a few years with the right tune and intercooled turbo....whats the most common failure on the M30...headgaskets?

cheers

SamE30e
05-26-2008, 10:17 PM
20 psi is do-able due to the CR.. but he said reliable... so to run 20 psi reliable he'll need a good tune... Which in turn costs more money.

I've seen 20psi on stock engine management, stock injectors, stock fuel pump. This guy knew what he was doing.

NOTORIOUS VR
05-27-2008, 01:32 AM
I've seen 20psi on stock engine management, stock injectors, stock fuel pump. This guy knew what he was doing.

BS.... I'll tell you right now the stock FP doesn't have enough to supply the fuel needed or the pressure needed for 20psi ESPECIALLY using a RRFPR.

He was BSing you and you obviously fell for it.

And you can't be that smart to run stock management @ 20psi the motor wouldn't last all too long.

The only somewhat believable part is the stock injectors due to the RRFPR, but none of what you said makes me believe the guy 'know' what he was doing. As people that know what they're doing don't hack together something like that.

90E30i
05-27-2008, 03:18 AM
I've seen 20psi on stock engine management, stock injectors, stock fuel pump. This guy knew what he was doing.

20psi with stock engine management?:confused:

You will need a really good tune even with an m30 if you are running 20 psi. You can have all the forged parts you want, but if its not tunned properly, its just a matter of time before something gives.

SamE30e
05-27-2008, 10:45 AM
He invented some insane vane metering valve that increased fueling mechanically. It was messed up but worked, this car pulled like a champ.

SamE30e
05-27-2008, 10:50 AM
BS.... I'll tell you right now the stock FP doesn't have enough to supply the fuel needed or the pressure needed for 20psi ESPECIALLY using a RRFPR.

He was BSing you and you obviously fell for it.

And you can't be that smart to run stock management @ 20psi the motor wouldn't last all too long.

The only somewhat believable part is the stock injectors due to the RRFPR, but none of what you said makes me believe the guy 'know' what he was doing. As people that know what they're doing don't hack together something like that.

Could be true, but he might seem to know what he's doing seeing as how he tuned Andy Frost's Red Victor 1. From what I gathered from him at the shop was that it was a stock 535i with turbo thrown on it and a couple little things (ex. Vane Metering Valve). One of them could have been a fuel pump.

NOTORIOUS VR
05-27-2008, 06:30 PM
Could be true, but he might seem to know what he's doing seeing as how he tuned Andy Frost's Red Victor 1. From what I gathered from him at the shop was that it was a stock 535i with turbo thrown on it and a couple little things (ex. Vane Metering Valve). One of them could have been a fuel pump.

The problem is not really the fueling... although I'll tell you right now if he was using stock injectors, he also has a RRFPR somewhere... as the stock 19# injectors don't have enough flow to support 20 psi without bumping the rail pressure way up using one.

The problem lies that with the old stock management, it doesn't know what positive pressure is... so regardless of what boost is going into the motor, it's always going to rely on the default ignition tables. And @ 20PSI on pump (maybe he was running race gas??) with stock tables isn't a good idea.

Also playing with the AFM (aka Barn Door) is nothing new... you can adjust fueling pretty easy by playing the the spring inside.

All in all, what I'm getting at it's not a very good setup.

SamE30e
05-27-2008, 07:56 PM
It was just thrown together, i'm sure it wasn't the best setup but it's out of the car for a rebuild right now.

BBR
05-27-2008, 11:47 PM
How much HP dos M50 with 10 ponds will mack

ACS_DAN
05-28-2008, 12:42 AM
http://forums.bimmerforums.com/forum/showthread.php?t=926330&highlight=turbo+m30

Dyno graphs for many Turbo setups on the M30.