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For a car that is turbo from stock i.e. e60 535i, Audi 1.8t etc. is it possible. Well I know it's possible... How envolved and what all needs to be done to run without turbo and only as NA? This question pertains to a certain race regulation. Thanks all for your time and info.

best to ask in a VW forum.
Who knows how the stock vw managment will handle that.

It's the most "envalved" part of it.

Other then that basically take the turbo off and make the
downpipe where the turbo used to be.

Ya. I imagined fabricating a replacement exhaust manifold. Anypart of intake n manifold need redone? Engine management need redone? I imagine stock ecu wouldn't know what to do. And depending on car year if it's capable of reflash or will need a new stand alone unit. Wonder what's more involving: adding a full turbo to a NA car or removing as asked? And which is less $$$?

Turbo cars are tuned under manifold vacuum and up to atmospheric too. The problem would be if the ECU would freak out if boost thresholds were missed. Easy to find out. Just disconnect the plumbing and see what it does.

Good idea. However, the project track car isn't purchased yet. Reason why I'm researching this matter. Cars in mind are a 1991 based ecu and a 2000 based ecu. I'm figuring the 2000 can be reflashed. But the 91 I have no clue.

Another issue I found could be the compression ratio. This is how clueless I am. But wouldn't a motor with a lower compression produce less power then an exact motor/head/valve match but higher compression? Hence if I removed a turbo setup, n do all the other stuff I'd want to replace pistons as well? Which in the end would all be pointless.

But in a perfect world. In a certain race where forced induction is not allowed. Wouldn't it be great and easy to remove turbo housing/cooling n reflash ecu?

its gunna run like an uber turd.Believe it!

If your question is whether or not its possible, sure, its possible. You didn't ask if it was a good idea. That it definitely is not.

The original question was how involved is the procedure. Is it as costly and invovling as installing a turbo setup. Novice race rules only allow for a 2wd or 4wd non turbo. Untill enough points have been obtained to level up. The reason for asking is because I don't want to buy a start vehicle and spend all the time preping it when I totally want another vehicle in the end. Hence the question and thought of... buying the vehicle I want. Removing the turbo piping and unit and reflash the ecu. Then re-install once I've aquired the proper licenses. The thought is easy but I'm finding, I might need to worry about a lot more then just remove turbo and manifold and reflash. I worry about compression etc... I just want to remove those things, get my points and re-install!! Damn it!!

I'd like to weigh in.

I'm running a VW 1.9L TDI in a naturally aspirated configuration right now because my turbocharger blew out. Honestly, it wasn't hard to do. I gutted the exhaust turbine, put a 15x1.0mm bolt in the oil feed hole on oil filter housing and put a rubber cap over the oil drain in the block. How involved was it? Took me about 2 hours, including putting in a silly little cone filter for the intake.

My ECU has no idea what is going on, and is running in limp mode. Imagine a 35-40HP A3 platform. Great fuel mileage though.

However, the stock turbos on things like a 1.8t, 1.9TDI, etc are just that. Stock turbos. In my experience with VW/Audi crap, the stock turbochargers are not good for much over stock power. And to put anything larger on there requires all sorts of things like aftermarket exhaust manifolds, downpipes, intercooler piping, etc.

So scenario #1: Get a stock turbo car, gut the turbo system, replace with N/A manifolds and downpipes, flash the ECU to run N/A, earn credits, place stock turbo setup back on the car, flash ECU for stock turbo setup and be stuck with the limitations of a stock turbocharger setup.

Scenario #2: Buy a N/A car, run a N/A car, earn credits, install a T25/T3 based turbo setup so you can play with hybrids and find replacements quickly should one bust, open the engine and do all the goodies to it, flash the ECU ONCE, do it right the first time and (hopefully) not have to redo it again.

CoyoteStarfish wrote:I'd like to weigh in.

I'm running a VW 1.9L TDI in a naturally aspirated configuration right now because my turbocharger blew out. Honestly, it wasn't hard to do. I gutted the exhaust turbine, put a 15x1.0mm bolt in the oil feed hole on oil filter housing and put a rubber cap over the oil drain in the block. How involved was it? Took me about 2 hours, including putting in a silly little cone filter for the intake.

My ECU has no idea what is going on, and is running in limp mode. Imagine a 35-40HP A3 platform. Great fuel mileage though.

However, the stock turbos on things like a 1.8t, 1.9TDI, etc are just that. Stock turbos. In my experience with VW/Audi crap, the stock turbochargers are not good for much over stock power. And to put anything larger on there requires all sorts of things like aftermarket exhaust manifolds, downpipes, intercooler piping, etc.

So scenario #1: Get a stock turbo car, gut the turbo system, replace with N/A manifolds and downpipes, flash the ECU to run N/A, earn credits, place stock turbo setup back on the car, flash ECU for stock turbo setup and be stuck with the limitations of a stock turbocharger setup.

Scenario #2: Buy a N/A car, run a N/A car, earn credits, install a T25/T3 based turbo setup so you can play with hybrids and find replacements quickly should one bust, open the engine and do all the goodies to it, flash the ECU ONCE, do it right the first time and (hopefully) not have to redo it again.

I'm not a Dr. or anything, but I get the feeling it's not good for your car to run for too long like that...

Thanks a lot starfish! Great reply. What I was looking for. All others helped as well.
Scenerio1: Newer car higher base price. But already turbo and higher performance potential. So could remove turbo setup initially then re install turbo setup to run with that. Then upgrade turbo setup after that.
Scenerio2: Older car a lot lower base price. Less power and less potential unless motor swap is allowed down the road. But could turbo stock motor as well at some point.

So after further 'spelling out'. It shows the desire for the newer car with more power at beginning and in end. But for a higher price and a lot more money after that. More of a headache n hard work to remove turbo. Put back on, then upgrade after that. Where as the cheaper route I'd be out there sooner gettin my points and experience etc. hunh?

Well, to me.. a stock turbocharged car does not have much room for improvement without changing the turbo, intercooler and pipes, and possibly exhaust manifold since most turbo applications made in the last 15 years have unique exhaust flanges and most aftermarket turbos are of the T25/T3 type.

I think we need to address the 3rd part of this equation, what sort of power do you want/expect?

Example, my 1.9L TDI. The stock turbo is only good for about 110-120HP and at this point exhaust gas pressure and temperature are in the danger zone. The engine comes stock with 90HP. This leaves relatively little wiggle room. To upgrade my turbo I need to replace my exhaust manifold. The stock boost pipes are very constricting and should also be replaced. The stock side mount intercooler (same as the 1.8t) is pretty useless with a small surface area and plastic end caps. The only part I can really reuse is the intake manifold, but with a larger front mount intercooler it is easier to get an European N/A manifold so my inlet can be on the other side.

So if you want to make more power than stock on the OEM turbo car lets look at the shopping list for a moment.
Car 1 with OEM turbo: larger turbo, aftermarket exhaust manifold, boost pipes, intercooler, maybe intake manifold, ECU tune.
Car 2 w/o OEM turbo: turbo matched to the power level you expect, aftermarket exhaust manifold, boost pipes, intercooler, maybe intake manifold, ECU tune.

So you need to buy the same things for both cars, only car 1 cost more initial money and then to conform to the outline you've laid out for us - you'll have to convert it to N/A by buying a N/A exhaust manifold and probably swapping out the exhaust downpipe and turning the ECU to run N/A.


Sounds to me like buying a turbo car, to go N/A, then turbo again - and being a race car - making higher power than stock would be much more expensive, time consuming and counter-intuitive than buying a N/A vehicle and then bolting on aftermarket turbo stuff on later.

And if you want to make greater power than stock on either the N/A or OEM turbo vehicle you'll have to pull the engine and do the lower end at the very least, which with the money you saved not buying all the extra bits to make an OEM turbo vehicle N/A then boosted again and then raising power level - would cover pulling the motor and putting work into it.

This is how I would do it given those rules.

skip535i wrote: I'm not a Dr. or anything, but I get the feeling it's not good for your car to run for too long like that...

I get that feeling too, but I gotta get around town one way or another.

if you are looking to temporarily deturbo a car then put it back see if you can find a computer/harness from a non turbo version of the same car that will plug into the rest of the car, if it exists then you'd only be slightly down on power from the turbo cam and lower compression.
the least sexy deturbo job i have seen was effective at least, it was a 740 volvo and they just unbolted the cartridge and bolted a piece of sheet metal over the hole in the exhaust housing left by it, this could possibly work in your case

What year and model vehicle is this being contemplated for and why?

If you give us more info, you're likely to get better answers.

winfred wrote:the least sexy deturbo job i have seen was effective at least, it was a 740 volvo and they just unbolted the cartridge and bolted a piece of sheet metal over the hole in the exhaust housing left by it, this could possibly work in your case

Same engine management and everything?

ghetto fab, they even piped the air though the intercooler instead of bypassing, car was a total dog and ran like ass. it ran like a low compression wimpy cammed car with a huge intake restriction that hadn't been tuned up in god knows how long

Xenocide wrote:

winfred wrote:the least sexy deturbo job i have seen was effective at least, it was a 740 volvo and they just unbolted the cartridge and bolted a piece of sheet metal over the hole in the exhaust housing left by it, this could possibly work in your case

Same engine management and everything?

Jeremy wrote:What year and model vehicle is this being contemplated for and why?

If you give us more info, you're likely to get better answers.

I didn't want to say since they both are not E28 nor Beem's...

But my E28 is still my daily... So, in that case it's ok that both cars being discussed are Audi's right? The older car of choice is a 90CQ 5cyl 20v NA and the newer one of choice is either a 92 or 2000 S4 V6biturbo. The reason why was stated in the beginning; for track/circuit use. The S4 I could buy once and go through trouble of removing turbo setup. Then reinstalling. Then upgrading later if I really feel the need. Where as if I bought the 90CQ NA once credits are earned and I'm upgraded out of Novice class I'd add more power. But the only way to do so is swaping the motor out for a 20v turbo. Which is almost an equal task imo; right? As the de-turbo'ing and re-turbo'ing... Those 20vTrb's are not really a dime a dozen imo. So the trouble of finding one, then sorting it out after I've sorted the NA version for initial track credit aquiring etc... Where as the S4 has the more power of the bat and greater potential for more... Think I really have to write out pluses and minuses as well as dollar signs.. In my mind now, the S4 is the way to go.. I'm just reall leary of harming the motor by de-turbo'ing and reflashing the ecu. and tracking it for a bit of races etc...
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