engine and drivetrain supercharging TPI vs. TBI: disadvantages/advantages?

[redphu72]

so I'm thinking of buying this white 1974 white 2002 out of Long Island, NY and its supercharged (roots type) mated to a built stock engine. Any concerns I should have. Seller said it was built by reputable shop (Eric Kerman).

http://bringatrailer.com/2010/08/05/bat-exclusive-pristine-supercharged-1974-bmw-2002/

[ClayW]

so I'm thinking of buying this white 1974 white 2002 out of Long Island, NY and its supercharged (roots type) mated to a built stock engine. Any concerns I should have. Seller said it was built by reputable shop (Eric Kerman).

http://bringatrailer.com/2010/08/05/bat-exclusive-pristine-supercharged-1974-bmw-2002/

TPI vs. TBI? I'm assuming that this question means that you're considering converting the car to electronic fuel injection, and you're wondering if you should go with Tuned Port Injection or Throttle Body Injection. Right?

TPI: The phrase "Tuned Port Injection" was actually invented by GM as the market name for their small block port injection systems in the 1980s. Essentially, it was port fuel injection with specifically calibrated runner shapes, but I digress. Port injection means placing a fuel injector inline with each cylinder intake. Its advantages include more accurate tuning and more efficient use of fuel, be it for fuel economy or for power.

TBI: Throttle body injection means adding one or two injectors within a throttle body, ahead of the supercharger in this case. This method is easier and cheaper to accomplish, but produces slightly less accurate and slightly less efficient use of fuel.

Both methods will see improvements in performance, reliability and fuel economy over the carburetor. It's really your choice.

That being said, in my opinion, $30K is a LOT to pay for any 2002 that isn't a factory Turbo. You can get an immaculate example for around half that price and do what you want with the drivetrain. This car seems really well sorted, but I can't justify that price.

[redphu72]

I love this site. Thanks for that little lesson. Having said that, should I run the car as is (supercharged/weber carb) or are the benefits worth the cost of converting to FI?

[ClayW]

I love this site. Thanks for that little lesson. Having said that, should I run the car as is (supercharged/weber carb) or are the benefits worth the cost of converting to FI?

The benefits of electronic fuel injection (EFI) over carbs (in any car; not just this one) include tuneability, reliability and efficiency. Remember that "efficiency" refers to the efficient use of fuel, rather for power, fuel economy, or some balance of both.

Again, however, I would humbly stress that this car seems a bit over-priced. There are many options for having a well-sorted, 200hp 2002 that cost a lot less than $30K. For example, after a glance at eBay, here is what looks like good `73 tii that you could upgrade to EFI, all for a lot less than $30K

http://cgi.ebay.com/ebaymotors/1973-BMW-2002tii-Roundy-Low-milage-Restored-/320843773180?pt=US_Cars_Trucks&hash=item4ab3c774fc#ht_500wt_1182

[BarryA]

car is pretty typical of a well done "custom" (doesn't really matter whether it's an '02, a '60's Camaro or a '56 Ford F-100), in that the seller is undoubtly asking significantly less for the car than the amount invested in it. From personal experience, it's unlikely that anyone without extensive mechanical, metalworking and painting skills (and the time and work space to complete a major project) would be able to duplicate it for much less than twice the $$.

Whether it's worth the asking price is in the eye of the beholder - for someone who wants a modified car, can afford the asking price, and doesn't have the time, skills or work space to build it, it's probably a bargain.

[redphu72]

car is pretty typical of a well done "custom" (doesn't really matter whether it's an '02, a '60's Camaro or a '56 Ford F-100), in that the seller is undoubtly asking significantly less for the car than the amount invested in it. From personal experience, it's unlikely that anyone without extensive mechanical, metalworking and painting skills (and the time and work space to complete a major project) would be able to duplicate it for much less than twice the $$.

Whether it's worth the asking price is in the eye of the beholder - for someone who wants a modified car, can afford the asking price, and doesn't have the time, skills or work space to build it, it's probably a bargain.

LOL. Believe it or not thats exactly what I wife has been saying.

[kk2tii]

If it's really making 200+HP why mess with a sorted out car?

[redphu72]

Im just asking because a little birdie told me that SC with carb set-up can be unreliable and suggested going the FI route altogether; in short pick a different car which leads me into:

http://www.bmw2002faq.com/component/option,com_forum/Itemid,0/page,viewtopic/t,368829/

Would this be a more efficient/cost effective choice? I would like to redo interiors, oem hood reinstalled w/ some fabrication, and finally paint.

[williamggruff]

I'm gonna have to get on board with Clay regarding the price. While the car looks great, and may have a fancy built m10 motor, for $30k you can pick up a well sorted M2 (a 2002 with an e30 S14 motor), or a 2002 with a 6 cylinder m20, and still have some money left over. Both will likely get you the power you desire without the super charger + carb tuning issues.

If your wallet can handle $30k for what amounts to be an entertainment purchase, something tells me you're reasonably well organized, and likely have some patience. I've noted that you've been in the market for a short while, and are looking primarily at well sorted cars. I suggest you keep looking. The market hasn't really heated up, so there are still lots of good bargains out there, including well sorted beauties with upgraded motors.

Best of luck with your search!

[jrkoupe]

red...

w/ all due respect ,...

.... I have read several of your posts, all about looking at specific cars in varying levels of mod etc...you seem to be all over the map, and money clearly does not appear to be a limiting factor. But you have spoken about several cars....and its not clear if you really know what you want, at all?....

are you mechanical>?....do you wrench on cars at all?.....change the oil etc?.....

you just seem to be spinning your wheels.....

sorry for my outburst , but Ive seen this white car as it has a FS vid floating around.

30K?.........really????...

[redphu72]

No worries I have been looking for a decent starter car with the intent of turning it into the white example that you see now. Not really into keeping it original, rather building a nice classic sleeper; hence my jumping around from one hit to the next.

I had decided on these two cars previously but was talked out of them and it seems like after all this searching, I'm back to square one; so I'm sticking to my guns and gonna chose one of the two. Just trying to decide which is better.

As far as being mechanically inclined, I'm a motorcycle track day guy, worked on bikes mostly. I'm very decent with my hands so I guess with the right manual and guidance, I can tackle the medium to the simple jobs.

red...

w/ all due respect ,...

.... I have read several of your posts, all about looking at specific cars in varying levels of mod etc...you seem to be all over the map, and money clearly does not appear to be a limiting factor. But you have spoken about several cars....and its not clear if you really know what you want, at all?....

are you mechanical>?....do you wrench on cars at all?.....change the oil etc?.....

you just seem to be spinning your wheels.....

sorry for my outburst , but Ive seen this white car as it has a FS vid floating around.

30K?.........really????...

[jrkoupe]

ahhh...I see.

Well if you know you want a modded hot rod type car then it is better to find one w/ the mods you kinda like.

At 30k or close, pls find a car that you like alot!......becuse at 30k Id want a car that was EXACTLY how I wanted it!

that white car is special for sure..owned by a guy that seemed to love it and have it well sorted......but it was HIS vision..is it yours?....

I bought a modded car knowing I wanted a hot rod......but the mods were basically the mods I wanted....and it was worth it.

the blu m20 car is A NICE CAR TOO.......

OH...DID U EVER SEE "Emily" FS...that was the SLEEPER to buy...if you had seen it youd never spend 30 on the white car...search the faq..youll drool.....or find Ian P's car...another nice hot rod...

the 2 of these cars will give you a sense of value.

[aa/fd]

In my roots experience the fuel supply on the intake side of the blower makes the rotors happier (cooler plus lube properties). But the port nozzle approach is a better for cylinder to cylinder tuning. Even though the 60 degree roots blower has a long rectangular opening 90% of the air flow is from the front of the case, so a combination of the two would be ideal.

All bets are off on any roots type blower with straight lobe rotors.

Any electronic fuel injection will be leaps and bounds better than a carburetor approach.

[ahlem]

I'd suggest test driving a stock e30 M3 and then decide.