Turbo on the SUPER cheap.

Keith Tanner said:

E85 is a wonder drug indeed, but if you don’t have an ethanol sensor plumbed into the ECU it’s a bit of gamble as the ethanol content can vary quite a bit.

Turbos are knock limited, so retarding base timing allows you actually run some boost and achieve your peak power. The downside is that it’ll be lazier off boost and won’t spool quite as fast. It’s a reasonable solution for cheap.

I like a high compression engine with a lot of timing off-boost, but only if I have the tools to make it work and those aren’t the same as “super cheap”!

So back to the idea of working within the boundaries of the original ECU- the actual spark and fuel map in the car is always extended beyond it's normal operating conditions.   As mentioned before- all MAF cars are mapped out to a load of 1 (real or not, the spark does retard the higher load beyond the data), and almost none of them actually get there.  And that map is generally safe.   Which means it's a reasonable thing to do to boost just up to the limit of the map and no farther- which is what was asked by the OP.

Add small turbo, with barely any boost, no mods, can you do that?  And for many cars, the answer is yes.  It's safer to use the highest octane you can get, but given the changes, the concept would certainly be safe.

Beyond that, then what?  Then you start looking at the suggestions.

Like the E50-E85 option- the best part about doing that is not having to open up the engine and lower the compression.  And given *most* of what would be done when you really go deeper into boosting- the rest of going to pump +100 octane fuel matches right up to it- aftermarket ECU, change in external hardware, etc.   For sure, if I were to do another Challenge Alfa, instead of cutting the original pistons down, I would keep them stock, go E85, and change the controller like I did way back.  As a matter of fact, I now regret telling John Brown that a boosted Miata w/o compression change was a bad idea (Sorry John, if you are reading this thread- your plan of a turbo Miata Datsun 2000 was going to be a blast...).

But back to the orignal question- add turbo and do nothing else- sure.  I didn't see that it was a BMW 318- and that's a MAF car.  Couple of lb of boost is something possible.

Exhibit A:

Turbo on a stock v6 with only minor tweaks for 'tuning' (MAP sensor car, we extended the harness to the MAP sensor and added hose with check valves so it never 'saw' boost) Super crude but it worked. Put nearly 100,000kms on the car with this setup. 3.5HO with a 3.2L ecm

When we dyno'd it, it was technically down on power BUT its a 300,000+ km engine and factory 21psi injectors fell on their face by 4200rpm (6500rpm redline) also none of the LH owners could ever produce a dyno sheet to support their claims as to how much I was 'down' other than quoting OEM spec power ratings. 

I think the biggest help was the vacuum actuated runner set-up. Under vacuum, the 'short runner valve' was closed so it would have a long tub runner so it had phenomenal low end torque, but out of vacuum, the runner valve is supposed to open to help ram air into the cylinder at WOT. The actuator system for that was a plastic boxy type thing that we pulled to not melt it. I later discovered how the system worked and set the short runner as part of the boost system, so when I was hard on the throttle it opened the runner and it didn't feel like a dog. 

We did upgrade the fuel pump and added a rising rate pressure regulator BUT that was before discovering that the manual boost controller I had got lowest setting was 15psi when it had been advertise at 5psi minimum setting. We then ran wastegate pressure and we were fine. 

In total, I think it was around about $500ish in parts to do it if I excluded relocating the battery, rebuilding the turbo (by choice) and a bunch of maintenance I did at the same time

Methanol injection might be a cheaper way of staving off detonation while maintaining spark advance than running 100 octane.

In reply to alfadriver :

Thank you. It helps to have someone explain things to us ill informed.  
The trouble is greed. If some's good, more is better, and too much is just getting fun.  
Seriously what would the expected out put of something like that?  20% gain in power over previous?  

We used to sell turbo kits with an FPR and retarded base timing for NA Miatas back around the turn of the century. I don’t remember the exact numbers, but they’d get you 50-60% power bump at least. It might have been more. We ran 6-8 psi if memory serves. They’d run for years if you put in a fuel pump that could handle the higher pressure. Most common failure mode was the FPR starting to lose effectiveness. Almost no ventilated blocks that I remember. 

Almost forgot about this. The boss turbo’d the shop T100. Welded a flange on to one manifold of the 3.4 V6 and stuck on a T3. Plumbed in an intercooler and used an FPR for fuel. 

And that’s it. Never touched the timing. Had some pretty good torque, I think over 300. You had to drive it with some sensitivity - it would knock if you loaded it up at a lower rpm, so you had to spin it out if you were climbing passes with a trailer. We used that thing to tow for years, and it kept running fine after we sold it to a friend with well over 100k on the clock. Was finally taken out by a drunk when it was about 15 years old.  

G_Body_Man said:

Methanol injection might be a cheaper way of staving off detonation while maintaining spark advance than running 100 octane.

Please please avoid methanol.  It's nasty stuff,  bad for anything aluminum or rubber. Horrible to the human body. ( a lot of my Sprint car friends didn't make it to 60). 
While  Methanol has 116 octane Ethanol isn't far behind at 114 octane. People drink ethanol in beer, wine, and booze. 
Since ethanol is in E85 it's also cheap! Right now I buy it at $2.09 a gallon. 

Methanol injection often uses windshield deicer. It doesn’t need to be pure, even water injection can be beneficial. But not cheap if done properly. 

In reply to Keith Tanner :

Drunk drivers suck

Keith Tanner said:

Methanol injection often uses windshield deicer. It doesn’t need to be pure, even water injection can be beneficial. But not cheap if done properly. 

My.windshield solvent is 10%  methanol unless you get the 40 below stuff which is 15%  a 55 gallon drum of methanol on the other hand works out less than $3.00 a gallon. 

I was not referring to the cost of the fluid. 

Keith Tanner said:

I was not referring to the cost of the fluid. 

I realize it is used to reduce or eliminate preignition/ detonation.  But E85 does much the same thing. For lower cost. $2.09 a gallon compared to near $3.00 a gallon when bought in 55 gallon drums. 

Having been down that road, there are many cheap and very unreliable ways to do it, and only a few expensive of doing it right. (It's one reason that turbos get a bad rap, because few people do it right and the result is a lot of YouTube videos of turbos blowing up.) Also, in the case of a turbo at least, if it doesn't blow up straight away, it's going to be VERY hard to resist increasing boost, then "poof."

A phrase I saw once which is both funny and true:

… a turbo engine is like having a cokehead pornstar girlfriend. There’s going to be unparalleled excitement and thrills, but a lot of unexplainable downtime and a likely violent ending that leaves you broke and insane…

Keith Tanner said:

It doesn’t need to be pure, even water injection can be beneficial. But not cheap if done properly. 

Like cheap scabby turbo setups, it can be done but you have to know what you're doing or at least have a feel for the process.

I've posted this vid before. This guy was a customer who was a super nice guy on a really tight budget so I helped him scab this thing together over the phone. It had  no aftermarket fuel management, was by most turbo installation standards a total hack job, and it just plain worked. He raced it like this for a couple of years and never had any problems with it.

It's a 3 cylinder tbi Metro with a mild cam. He has a better run posted but the sound is not good

Geo hill climb

^ and likely had the boost set low enough to keep himself out of trouble!

frenchyd said:

Keith Tanner said:

I was not referring to the cost of the fluid. 

I realize it is used to reduce or eliminate preignition/ detonation.  But E85 does much the same thing. For lower cost. $2.09 a gallon compared to near $3.00 a gallon when bought in 55 gallon drums. 

With methanol injection, methanol isn't used as fuel. It's just be atomized into the intake to bring down IATs. More consistent than pump E85 and it won't damage fuel system components. A lot of N54/N55 guys swear by it as a way of preventing knock under high boost.

The problem is failure modes. 

When your injection tank runs dry/nozzle clogs/pump fails, you need to know because your engine is depending on it to live. The best way to do that is a flow meter and a big honking light on the dash. You find out about problems with detonation, which can be a problem if you’ve gone all racecar and made it loud.

With E85, you either have to tune to the minimum ethanol content and ensure you never have any less, or you buy your fuel in drums and never fill up away from home.  You find out about problems with detonation.

With an FPR and a timing retard, you can see a problem with a wideband.

Buying fuel by the drum is a pain in the behind. We lost our local E85 sources here so the high boost turbo guys have had to go that route, and a lot of them have gone away from E85 as a result. Methanol injection is a lot easier to live with but again it’s proven to be more trouble to set up and maintain than most guys are willing to deal with. 

Neither are part of SUPER cheap turbo. 

Depending on how "cheap" you consider it, the Audi guys who used to hang turbos on the V8 (same exhaust bolt pattern as Volkswagen 16vs)  would just install two head gaskets per side to drop the compression on a $500 junkyard 4.2.  No piston work or anything.

It makes me cringe to think what it does to the quench height, but apparently once you're over .080" of clearance or so, it doesn't matter anymore, and Audis tend to have crappy-low levels of squish anyway.  Regardless, people were easily running 9+ pounds of boost into them, which is really way more power than the drivetrains or chassis could handle, so why go deeper into building the engine?

Keith Tanner said:

The problem is failure modes. 

When your injection tank runs dry/nozzle clogs/pump fails, you need to know because your engine is depending on it to live. The best way to do that is a flow meter and a big honking light on the dash. You find out about problems with detonation, which can be a problem if you’ve gone all racecar and made it loud.

With E85, you either have to tune to the minimum ethanol content and ensure you never have any less, or you buy your fuel in drums and never fill up away from home.  You find out about problems with detonation.

With an FPR and a timing retard, you can see a problem with a wideband.

Buying fuel by the drum is a pain in the behind. We lost our local E85 sources here so the high boost turbo guys have had to go that route, and a lot of them have gone away from E85 as a result. Methanol injection is a lot easier to live with but again it’s proven to be more trouble to set up and maintain than most guys are willing to deal with. 

Neither are part of SUPER cheap turbo. 

As the real estate lady says, Location, location, location.  At least 20%  of gas stations around here have E85. There are web sites that show where they are.  I buy it regularly for my flex fuel pickup just because I save about $10.00 a tankful. $2.09 vs $2.59 
In the Winter when E85 drops to 51%  you can still buy denatured alcohol at the big box and hardware stores to kick your ethanol percentage up.  Plus the circle track boys always have sealed drums of  denatured ethanol ( 98% pure ethanol) they will open and sell you 5 gallons at a time.  (They get $3.00 a gallon for their trouble)
 

As for management I saw some mention of running a piggyback on the ECU called an ostrich. I've briefly messed around with one of those in my friends early 90s turbo Accord.

Keith Tanner said:

The problem is failure modes. 

When your injection tank runs dry/nozzle clogs/pump fails, you need to know because your engine is depending on it to live. The best way to do that is a flow meter and a big honking light on the dash. You find out about problems with detonation, which can be a problem if you’ve gone all racecar and made it loud.

You can run a fuel pump and single injector using one of the timer circuits I mentioned before and monitor pressure via a pressure switch wired to a control circuit. This kind of system actually works very well for water/methanol injection. Being RPM based and pressure referenced it's pretty easy to size and stay within the correct percentages

In reply to kb58 :

14 psi. 3 cylinder metros need a fair bit of boost to get them to spin on turn exit

Out of all the replies, shutting off the return line is my favorite so far. 
 

For those that are arguing ethanol over methanol obviously haven't used both. Methanol is a pain from compatibility and fuel flow but will make quite a bit more power than any e85-e98 (even race gas based blends). You can still use stock na timing tables up to a good bit of boost (usually around 25-30psi) so that solves one problem ;)

In reply to Paul_VR6 :

I have used both. From a safety standpoint keep away from methanol. It's flat dangerous. Get it on your skin and is goes straight into your organs, enough and you die.  Look at how NHRA mandates  it needs to be handled. They require a full face mask   And respirator so you don't inhale  it. Plus a rubber apron,  full length rubber gloves etc 

Not to mention the way methanol attacks aluminum etc.  which Ethanol doesn't. In order for ethanol to do damage to aluminum it has to be exposed to moisture long enough for it to absorb a heavy percentage of water and then remain in the aluminum long enough for the water to corrode the aluminum. Methanol can damage aluminum overnight.  

Yes methanol is 116 octane to Ethanol's 114.  Yes you can buy unaltered methanol easily. Because unaltered ethanol is pure booze. 
E85 is around 100 octane depending on what gasoline is mixed with it. If mixed with high octane racing gas it's going to be higher than 100 octane. 

Nope already converted to the lords alky and my car is setup for 50% nitro so no lectures needed here. 

In reply to Paul_VR6 :

I salute your bravery.  Hopefully you've got experience working with nitro.  My limited experience goes back to the 1950's with a neighbor who raced a Offenhauser powered sprint car. By the late 50's small block Chevy's were solidly kicking butt on Offy's. 
in order to qualify for the Minnesota fair sprint car race he was forced to add about 5%  nitro. Hillborn fuel injection works on bypass. The bigger the hole in the "pill" the leaner the engine is.  He went from about a 1/4 inch hole to one a needle would get stuck in.  In other words,  massively richened the engine up.    I can't imagine how much would need to flow through to meet the 50% number.  
pretty sure double wouldn't  begin to cut it