You should be alright with the 64 A/R. I was worried you may have used the 48 A/R that comes on a lot of the 50 trims or even worse I think there is maybe a 30 A/R. It is still going to spool pretty darn quick though, but the 50 trim has one of the best compressor maps in the TO4E family.

I stoped in my post & went and ran the numbers threw a turbo calculator. Going with 90 % effiecent engine that turbo is maxed out on both ends of the scale, it sould spool super quick. But even if it full spools by 2000 rpm it should not be in surge, it would have to full spool around 1200rpm before it looks like it would hit surge so you should be fine on that end.

Where it looks like your cutting it close is on the stall line. You may want to keep your RPM down to 4800 or even 4500 RPM to keep from over spinning the turbo.

I will be very interested in your final results. I am planing on using two turbos about this size on a long rod engine ( GT3071r). I kinda hope you do hit full spool at about 1500 rpm ( but without problems ).


A whole lot of variables come into play when trying to use a turbo calculator to match up to your engine. Some times the real world test is all that will tell you the truth. Compressor maps & formulas dont always work just as they say. So in the end until you do it you really dont now the results you just have a educated guess.

But as I said before, take small steps and check everything as you go and dont just assume something is alright, do what it takes to know and you should be fine & end up with a great running setup.

Get that EFI going as quick as you can, I worry about uneven cylinder fuel distribution on the slant six intakes ( having one cylinder lean when the others are fine). A infra red temp gun used on the exhaust runners can help you here alot. Run it in boost & quickly pull over & take readings of each exhaust runner & look for even temps between them. And ofcourse plug reading at each level you go up to. Remember plug reading is more than just looking for white or tan plugs, you need a Jewelers Eye piece to see the whole story. And a new plug on the cylinder you are testing with a full pull on the power & quick shut down & read the plug then to get the truth also.

There is alot of info out there for all of this, if I can help in anyway just let me know I will do what I can to find your anwsers for you.


Jess

I was going to do a twin turbo setup, I made some adapters to connect turbos to Dutra Dual manifolds. I didn't build it because of the cost of the turbos. So I put together a single turbo setup. My turbo project is more than just a turbo on my car. I plan on casting a turbo manifold for a slant six. Originally I was going to cast something similar to Dutra Duals with a turbo flange on the front manifold and a new rear manifold that would clear the starter and bolt on a turbo. I will probably cast a single turbo manifold and I will need to change the location of the turbo because I would like it to fit on a 170 block, I would also cast in a provision for a external wastegate.

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1966 Signet
Turbo Slant Six

Rob,

Looks like a nice setup, and I'm anxious to hear how it goes down the road. Might entice me to finagle a SF area trip in the next year for a ride...

Lou

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Home of Slant6-powered fun machines since 1988

I will probably take the car to the muffler shop on tuesday. I did the trans kick down today and took care of a few other loose ends. I put a 8 3/4 rear end in the car so I still need to hook up the back brakes, that should happen tomorrow. I am looking forward to the first test drive.

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1966 Signet
Turbo Slant Six

Wow! We'll be watching your progress. Looks great. Congrats and good luck. I'm printing the pics for my V8 "friends" that dog me about the /6.

I have to agree with Jess (LUCKY13). My 2.2 5 speed LeBaron came from the factory without a BOV, and it was set for 12 psi. Note, that's a factory stick car, without a BOV.

Are they a good thing? By all means. Are you guaranteed to scatter the motor without one? Not at all.

Rob, sweet stuff. I was surprised to see it with a carb as your earlier pic had the EFI intake. It makes sense though after reading your posts.

I'm waiting with baited breath to hear how it runs.

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'15 Chrysler 200S V6
'74 Duster 360, factory 4 speed car

That was also a FI engine not a carb engine, with floats that can colaps, or push fuel out the float bowls. I was not thinking about the engine it self. The pressure will stay above the carb butterflies. I was concerned about the carb and the turbo system

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

But a BOV isn't going to reduce the boost pressure any, unless I am misunderstanding, and if the BOV doesn't reduce the pressure, a carb float and bowl isn't going to see a change with or without one.

It's my understanding that all a BOV protects is the compressor blades. The shockwave that the blades hit could bend them. It also keeps the compressor spinning (because there isn't a shockwave trying to stop it), there by improving performance. Those are the theories I am familiar with, anyways.

I agree it would be a good thing to have, I just don't think it is the end of the world you he doesn't. In fact, if I had gotten mine up and running with a carb (not the plan anymore), I wouldn't have had a BOV on mine.

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'15 Chrysler 200S V6
'74 Duster 360, factory 4 speed car

I am not an expert, by any means, but: my turbo is a draw thru.
If I understand the function of a BOV, it serves a couple of functions.
1: as stated is to relieve the back pressure between the compresor and the throttle blades, to allow the compresor to stay spooled up.

When running with the throttle wide open and the boost at the desired max level, then let the throttle snap shut, the compresor, keeps spinning and flowing air. This air has no place to go, so a pressure spike occurs. This spike can damage the turbo, but can also damage the carb. Normally the BOV will be set just slightly more pressure, then the waste gate.
For example: waste gate set for 10 psi, BOV 11 psi. The BOV doen't limit the boost. If the throttle slams shut, the pressure spike tries to go to 20 psi (just picking a number), the BOV would open, and limit the pressure in the piping between the compressor and the throttle blades to 11 psi. This would protect the carb and the turbo.

Maybe Tom Drake could either confirm my understanding of this, or shoot me down in flames

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

This much I do know. The BOV isn't set for a pressure, it is hooked to a port on the under side of the throttle blades so that when the throttle is shut, the BOV sees vacuum, which opens it.

The only pressure setting I am aware of for the BOV is to make sure the spring pressure is strong enough to keep the BOV from leaking boost at your limit, i.e, if the BOV is good for only 15 psi, and you try and run 20 psi, boost will push the BOV open and you will be frustrated with inconsistent boost pressure.

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'15 Chrysler 200S V6
'74 Duster 360, factory 4 speed car

Here is a sight with some more info. The guy isn't perfect, but he has a wealth of useful info. BTW, not sure this clears anything up, but thought I would share.

http://thedodgegarage.com/turbo_bov.html

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'15 Chrysler 200S V6
'74 Duster 360, factory 4 speed car

And it was also a draw-through, wasn't it? A BOV is neither desirable nor possible to install on such an engine. I had a later turbo LeBaron with the blow through throttle body, and it did use a BOV.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Nope, '89 LeBaron GTC, 2.2 Intercooled 5 speed, blow-thru. Max boost, 12 psi. The draw-through setup was '87 and older, only.

But you are right in that a draw though doesn't need a BOV as the turbo sees vacuum when the throttle closes.

The only Mopar turbo cars to get a BOV where the '88 and up auto and some manual, and all TIII's, if you don't count the later turbo cars (PT and SRT-4). Interestingly, it seemed that Ma Mopar was more concerned with the auto than the manual.

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'15 Chrysler 200S V6
'74 Duster 360, factory 4 speed car

I am by no means no expert either. But I have built & raced about 10 turbo street/strip car & always do alot of reading & research on things. Never take what you are told for gospel, do your research.

With that siad here is my thoughts on it.

The manual is the one that really needs a BOV the most as far as keeping turbo spooled & protecting against shock. With the Auto there is no drop in RPM on shifts so no need & when letting off the throttle you have a "little cushion" from the torque convertor. But your throttle is still closing no matter which tranny.

The Carb would get more abuse than the EFI sytem for sure. As far as the floats you should have a float that is made for the setup anyway(none crushing). But I could see fuel getting forced out of tubes or something or even bending a throttle plate if boost was at a high pressure, wouldnt be very good if it happened thats for sure. But damage to the turbo is the main problem. Even if no damage happens to the turbo blades it does put more pressure on the Bushing/bearings & over extended time even a low boost setup can wear the turbo out quicker without a BOV.

But if things are keep reasonable like 10 psi & caution is used it should make it through some test driving with out failure. And on a Auto it probably could even be left this way at this PSI level. But it is better & safer to have one without question no matter what PSI you was running. But the bigger the turbo the more the need for the BOV, 10 PSI from a large turbo is alot more air than 10 PSI from a small one, so aot more load & more chance of damage. One of the best fatory BOV you can get is off 90 91 Eagle Talons, there is even a mod you can do to make it hold up to 30 PSI from adding a vacume source & can even be controled with a vacume soliniod & a switch to change from 15PSI to 30 PSI capabilities. But if you have to buy one instead of salvaging one the Tial 50 BOV is a good one to consider. The EBAY guys have copies of these that work just fine and are alot cheaper, just dont buy there turbos. Wastgates & BOV & intercooler copies that they sell are fine & proven to work very well & durable and perform as good as any others. Turbos are another story & have even been seen to come apart at the compressor & other fun stuff so stay away from the turbos.

Here is one for instance from EBAY.

http://cgi.ebay.com/ebaymotors/BRAND-NE ... enameZWDVW


Jess

Thanks for those links. I learned some more. I was correct about the purpose of the BOV, but wrong about how it was acuated.

A day with something new learned, is a day not wasted

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225