1977 odd fire 231 turbo

[gdouaire]

Good evening all,

I'm building a turbo 1977 odd fire 231 V-6. It will run around 7-9 PSI boost, maximum. I have purchased a GN Turbo kit on ebay, and am planning to use a OEM GM TBI setup from a 4.3 Chevrolet in "pull" setup, no intercooler.

Isky sells a neat Odd fire turbo cam, 208/194 1171-TA "Turbocycle-A".

Aside from that, my intent is to keep the engine stock (if not a beefed-up oil pump) and run it with a 200-4R.

My guess is that this setup will show good performance and acceptable economy in a G-Body. Thoughts?

 

[earlbrown]

Post a link to that Ebay GN turbo kit and let us see what you're working with.

Nothing wrong with leaving it stock. No reason to spend a fortune on a project engine just for fun. Defiantly freshen up the oil pump and do some flow mods. A tired 70's pump won't keep the rods off the crank at low RPMs. 2004r is nice to with the OD. No idea on that cam. As long as it doesn't have a bunch of overlap and hold the valves open too long you should be fine.


using GM TB setups in a retrofit FI setup isn't new. I've been wanting to build one myself for a slant 6 in my van I don't drive

 

[charlief1]

The odd fire engine has some issues that you haven't counted on. No other intakes, other than stock, are now made to fit it so you've got to find one of the old Holley intakes like I've got sitting here. The other issue is that the firing order is 100 and 140 degrees alternatively if I remember right. You might be able to do a blow through with a carb but if you plan on a trigger for ignition control you're screwed since the 4.3 doesn't have the same firing order. Draw throug is the other option unless you want to do everything from scratch and make it yourself. In late 77 they made the even fire and the intake won't interchange, and then in 79 the heads were changed and same issue.

Cooling passages were changed as well as EGR in late 77 so you're stuck with only heads built in 75 to early 77.

 

[gdouaire]

thanks for the feedback. I'm not allowed to post links yet (too-new user), but if you search for item # 190776552327, you will find the turbo kit I am using - they call this "T04E racing turbo grand national blah blah...".Some people say it's a terrible brand ( the turbo is made in China ), I'm assuming that it would matter if I wanted 14 psi of boost, but keeping it lower may improve reliability. And lots of oil flowing would help, I suppose.

As for the lack of interchangeable parts, noted. I knew about the heads, but not the intake. Since it's a mild build I'm aiming at, I'm thinking it won't limit me much.

I have a guy who is testing an odd-fire setup for me, including ignition triggering. I've seen someone making this work on the internet - he used a magnetic crank trigger on the vibration damper. Again, no link here, I'm not allowed to post them yet. May sound a bit complicated

 

[Pittsburghkid]

Here's what you're going to run into with those headers.

http://www.turbobuick.com/forums/threads/speed-daddy-headers-for-hot-airs.388963/

 

[MeanBuicks]

I thought the odd-fire bowed out after the 1976 model year, no?

 

[dr_frankenstein]

Other questions......


Is this draw thru TBI or blow thru? The TBI is very very limited on boost since anything more then 22lbs total will shut the injectors down, so 12psi fuel pressure plus 10 psi boost will crap em out. Have that issue on my S10 with a similar eBay turbo. And i have been tooo and back trying to get more from the tbi...So blow thru is a waste of time and draw thru will have issues without providing a method of boost enrichment which would require a FMU or 7th injector of sorts plus the eBay turbo is not carbon sealed.

Just speaking from experience regarding TBI and boost.

Also remember since these are Chinese turbos they are copys of American counterparts and thus they may not run well at lower boost levels as they are designed around a specific P/ratio and the slight changes made to prevent copyright infringement hinder the units when they are outside of the design specs.

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[gdouaire]

Thanks for the feedback.

Looks like I'll have fun with header fitment My set is different from those pictured in the thread, hoping I'll get a better fit... but I may get a worst fit I will post my pictures on that header thread for sure.

I think a "pull setup" with TBI is worth the try - I'm trying to avoid pressurizing the TBI system...but your points are well taken. I forsee a lot of adjustments. As for the carbon seal, I'm looking into a rebuild kit - hopefully, the seals from my DNA motoring turbo will be compatible with a Garret kit. Even with the rebuild kit price, the Turbo is still affordable.

I guess I'll learn a lot. And will need a lot of patience.

 

[gdouaire]

MeanBuicks - the oddfire V-6 were phased out in mid-1977 from what I read. Mine came from a 1977 Pontiac Sunbird...

 

[dr_frankenstein]

Thanks for the feedback.

Looks like I'll have fun with header fitment My set is different from those pictured in the thread, hoping I'll get a better fit... but I may get a worst fit I will post my pictures on that header thread for sure.

I think a "pull setup" with TBI is worth the try - I'm trying to avoid pressurizing the TBI system...but your points are well taken. I forsee a lot of adjustments. As for the carbon seal, I'm looking into a rebuild kit - hopefully, the seals from my DNA motoring turbo will be compatible with a Garret kit. Even with the rebuild kit price, the Turbo is still affordable.

I guess I'll learn a lot. And will need a lot of patience.

I love it! I was on the same track! Here's where it makes it difficult in this process. The backing plate for the turbo itself will dictate the seal design used. If the turbo is dynamic then your stuck there because you need the matching carbon seal plate to work foe the pull thru use. The seals do not interchange and I learned this the hard way early on. Best course of action really is to try and locate a 86/87 unit as it has the best flow for carbon seal for the price.


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[charlief1]

MeanBuicks - the oddfire V-6 were phased out in mid-1977 from what I read. Mine came from a 1977 Pontiac Sunbird...

You're correct. The odd fire was removed from production in mid 77 to make use of the even fire because of engine vibration. The even fire didn't rock as much in the chassis so customers were happier.

 

[gdouaire]

The seals do not interchange and I learned this the hard way early on. Best course of action really is to try and locate a 86/87 unit as it has the best flow for carbon seal for the price.

uh-uh. this is getting fun

Dr Frankenstein - did you end up using what they call a "Encapsulated Carbon Seal" or a "Four-piece Carbon Seal"?

I bought a "Turbo Rebuild guide and Shop Manual" to start learning more.

Luckily, I'm not in a hurry, doing this on a spare engine

 

[dr_frankenstein]

uh-uh. this is getting fun

Dr Frankenstein - did you end up using what they call a "Encapsulated Carbon Seal" or a "Four-piece Carbon Seal"?

I bought a "Turbo Rebuild guide and Shop Manual" to start learning more.

Luckily, I'm not in a hurry, doing this on a spare engine

Well the dynamic seal is like a piston ring, so the back plate doesn't have the recess for either of the carbon style of seals. That's where the problem lies. You need a specific "carbon seal" back plate for either design and the 4 piece was my preferred choice. The 4 piece drags less then the other and frees up some spool.

Ultimately the stock 86/87 unit will do the job well and is already carbon sealed and can be bought used for 100-200 bucks... it out flows a carb 301 turbo by a mile just on housing shape alone. I only make such a strong suggestion to save you from the eBay experiment.

A.j.

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[gdouaire]

I've read interesting stories about people running a "pull" turbo setup with dynamic seals... a lot of oil in the engine was involved!

On the other end, there are T04E backplates for carbon seals available out there for 50$. Ebay item #151089360509. I'll go for that, looks like a genuine Garrett, need to confirm with vendor if it's carbon-seal ready.

 

[dr_frankenstein]

I've read interesting stories about people running a "pull" turbo setup with dynamic seals... a lot of oil in the engine was involved!

On the other end, there are T04E backplates for carbon seals available out there for 50$. Ebay item #151089360509. I'll go for that, looks like a genuine Garrett, need to confirm with vendor if it's carbon-seal ready.

Yes that is the correct backing plate, but you will have to have the back plate machined to fit the compressor wheel. As the plate on eBay is a blank. Dilemma number 3! Lol

A.j.

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[gdouaire]

plate on eBay is a blank

Really? I looked at a bunch of other backplates and used/installed ones are identical - there's a groove and I guess it needs to be the right diameter to fit your compressor...