Need some advise

[gsmith660]

I need some real opinions here, I read where a guy did a low boost turbo application on his car and i don't think he did any mods to lower compression ratio I have a 2.7 recent upper end overhaul stock or close to stock comp. ratio I am installing a 3.2 intake and EFI. Parts on hand are a stock K27 I had rebuilt, wastegate that needs rebuilt, complete exhaust a small but good intercooler, and electric scavenge pump plus some other dodads and such. What do you think serious answers only thanks. I dont think the K27 is right for what I want but some of the other parts might work.

What I have been doing for the last 2 years!

This is my build thread that I have posted on but it was suggested that I might post also here to get some expert opinions on a direction I might go?

[RarlyL8]

Wow, spectacular progress!
I've seen your car before in brown, gotta say I love the blue.
The 2.7 case does not lend itself well to the heat created by turbocharging, but for a street car you can get around that. There are a few turbocharged 2.7's on the board. With the Carrera intake you can use the same turbocharging kit as the 3.2L engines. Lots of info on that. The smaller displacement of the 2.7L should make the typical 3.3L K-series turbos act as if they are larger units and result in larger % power gains than you would expect on an engine with an additional 600cc of displacement.

[gsmith660]

I was thinking of using this motor as a test bed and I have another that is ready to be put together to spec, I figure out from this motor I was thinking along the lines of a little rat racer, the case I have already has case savers, I was thinking of taking it some where to get it shuffle pinned, this motor ran real strong until I overheated it and then it leaked real bad cause the case halves split, any idea how the best way to lower compression is (spacer or machine the heads). When I get compression down to 7.5 then I was thinking 1.5 bar of boost the test motor will be limited to .5 bar of boost. Am I thinking in the right direction or completely full of s--t. This is purely a experimental project I know in the old days Porsche put out some small displacement motors that had some real power to them.

[RarlyL8]

Typically the 3.3L 930 engine cannot handle more than 1.0bar on pump gas as longevity becomes an issue. This is at 7.0:1 CR. I would think the 2.7L even less robust.
The small displacement engines such as "Baby" were highly modified.
A purpose built turbo engine can get you crazy power at low boost levels. Very expensive proposition. You may consider purchasing a Carrera or 930 engine as a better base if going for >350WHP.

[gsmith660]

So 7 to 1 huh, ok I was under the impression that the 7R case was pretty strong and if I use best quality head studs then the grenade factor of the motor decreases. What do you think I am open to any suggestions I have followed some of your work and I think it is great. What do you think of the bolt on idea as a test bed at .5 bar and also ideas to lower compression ratio.

[gsmith660]

To answer your last question I am just playing with what I got, if I need to go to the bigger displacement engine then it is possible at a later date but right now if it just isn't feasible with a 2.7 then I will just go in the direction I was going with the EFI.

[RarlyL8]

There are a couple guys here with 2.7L turbocharged engines. They need to chime in ...

[gsmith660]

please do ! I need all the input I can get. I am looking to get my feet wet and experiment I have a iphone and will get the dyno programs that they are all talking about so I will have a way to plot my progress without using a dyno which is non-existant around here.

[gsmith660]

RarlyL8 thanks anybody else please I need ideas.

[RarlyL8]

If I were doing this with the components you list I would set the boost at 0.5bar and go from there. One of the keys to longevity is proper AFR's. With your Carrera injection you will have that handled. Steve Wong makes a turbo chip for the Motronic that will make this easy for you.
Another important issue is cooling. Given the history of the 2.7L engines I believe you can head off the worry of heat-stressing the block by going overkill with the coolers.
I'd go for it. You have the knowledge and equipment to do it right. Start off with low boost and move up as you tune and learn. A head temperature sensor (or two) wouldn't hurt either.

[gsmith660]

Originally Posted by RarlyL8

If I were doing this with the components you list I would set the boost at 0.5bar and go from there. One of the keys to longevity is proper AFR's. With your Carrera injection you will have that handled. Steve Wong makes a turbo chip for the Motronic that will make this easy for you.
Another important issue is cooling. Given the history of the 2.7L engines I believe you can head off the worry of heat-stressing the block by going overkill with the coolers.
I'd go for it. You have the knowledge and equipment to do it right. Start off with low boost and move up as you tune and learn. A head temperature sensor (or two) wouldn't hurt either.

I will be using the bitz EFI and I am talking to Tony Bitz about the tuning the system is really easy to set the afr's throughout the rpm range so thats covered as for cooling I have a big turbatrol oil cooler up in the fender that will provide ample cooling I bought this long ago with this in mind and .5 boost was what I was thinking also. The bitz system has CHT sensors but I may add more and monitor with a gauge also will be using a wide band O2 sensor with this thanks for your help I really thought I would get more ideas from others as this is for fun and I have no intentions of grenading an engine but I do intend on building an engine worthy of the 315's I will be putting on the back.

[gsmith660]

Here are the parts mocked up.

[gsmith660]

What is the best location for the thorttle body before or after the turbo?

[RarlyL8]

The throttle body is located after the turbo and orientation of the throttle body is dependent upon intercooler piping/design. I have a few pictures of intercooled 3.2L engines that might help you to visualize this. You should check the archives for threads on the subject of turbocharging/intercooling the 3.2L Carreras.

That setup you have pictured will work but is restrictive. The thermol reactor replacement manifolds offer no heat and poor flow quality. The early USA cross-over pipe may work better for a 2.7L engine than it did on the 3.3L 930. Wastegate inlet is less than optimal but again may work adequately for you. Good place to start as you can make changes later on if desired.

[gsmith660]

I searched many combos on your search string and found nothing is it this forum or the tech forum. Thanks for the input on the headers that is what Martin suggested for my application but the final take on this will have heat that is for sure.

[lite75]

Hi,
I have a complete euro exhaust system for $135., if interested PM me.
Dan

[gsmith660]

Anybody know where I can get a .5 bar wastegate spring.

[gsmith660]

I don't have a 930 oil tank which brings me to another question any ideas on a place to dump the oil from the scavenge pump, I was thinking of either getting a tank that the oil pump could dump into as well as the crankcase breather and then that would go to the oil tank. Whatcha think?

[gsmith660]

most boost controllers leave manifold pressure unrestricted to the bottom of the diaphram and have a valve throttle pressure on top of the diaphram to make mainfold pressure hold the valve closed longer therefore higher boost, by this same theroy can I move the valve to below the diaphram and unrestricted to the top and thus I would be able to make a .8 bar spring open sooner to limit my boost. Am I in the right neighborhood or does it not work this way?

[gsmith660]

Thanks everybody who responded I think I have all my ducks in a row and am looking forward to digging in. When I get started I may be posting back as well as progress.