Inliners International Forums General Discussion Blown and Injected feasibility of low boost turbo project...

hi all... for a couple of years i've been thinking about a very modest turbo for my engine... a Rambler (Nash) 195.6ci OHV. This is a trough-intake design, a fairly terrible engine. Factory rated at 125 HP, in a car with a T-96 trans and an 8" clutch.

Loooong stroke, small bore, interested in drivability 1500 - 3000 rpm. I run it to 4500 *occasionally*, pulls fine, but this is an old slow-turner... I'm not interested in racing or breaking expensive rare parts. In this light car ('63 Rambler American) an additional 25HP would go a long way.

Engine is new, very careful build, balanced, polished pistons and combustion chambers, converted to full-flow oil filtration, Nash-era head cooling flaws fixed. All broken in and sorted out. EDIS/MagaJolt ignition, Weber 32/36 carb, big exhaust. That side of the engine compartment ready -- battery is in the trunk, gennie gone, alternator on the other side. Mounting worked out, and i can mount my exhaust mani upside down, pointing up!

I did a lot of work on this engine, doc'd here: http://wps.com/AMC/195.6OHV/index.html

ARP head studs, but old-fashioned composite headgasket, and this engine prone to head sealing issues. I think I solved those. Not interested in pushing things too much. More than adequate cooling system with computer-controlled dual electric fans.


QUESTIONS:

Is it reasonable to size a turbo such that it won't overboost by redline? eg. let me skip waste gates and all that? Engine redline is 4500 rpm, but it now goes there smoothly.

I really want draw-through with my current carb. I know this means a carbon seal turbo or equiv. I will have to weld up my own plumbing so i can put a blowoff valve on it. Is that enough for draw-through?

I worked out specs (spreadsheet or tuner software) but had a hard time turning specs into a suitable passenger car donor... new is too $$$$. Also, I need a TINY turbo, and too much hot-rod and import-scene stuff are far, far too large.

Is small-gain boost doable/practical? 25 hp or so?

Am I crazy? OK don't answer that (I drive Ramblers)

i have been interested in the extensive turbocharging experiments performed on Studebaker Champion sixes -- an engine even smaller than your Gnash, and a flathead to boot! See

http://www.studebakerdriversclub.com/documents/TurbochargingtheChampflatheadsix.pdf

i don't think i'll do this, but it is fascinating. On the basically stock Champ they recommend a Chrysler 2.2 TO-3 or a Buick Regal TO-4. That might get you started. Since you have demonstrated some gifts for this kind of ingenious engineering, i'm going to be watching what you do with great interest.

God's Peace to you.

d
Inliner #1450

There are web-based sellers with chinese knock-offs of turbos. These can be had for less than $200 new. I chose to go this way so that I could experiment with a cheap turbo, and once the application is working well and or the turbo itself fails, I can substitutue a more desireable turbo with little effort. The outfit I'm thinking of, called something like red-line max, does have quite a few smaller units.

Turbos designed for Diesel engines are made to provide higher peak boost levels at low RPM compared to those made specifically for gas engines that rev higher. Diesels typically only have a 2500-2800 RPM ceiling on them, so all there boost comes in before then. Mine can have 25 psi at around 2000 RPM if im pulling a heavy trailer.

Thanks for the steadybreaker link Don! It's very heartening, since they're going after so big a gain with so small and old a motor. That much HP out of that little thing is impressive!

OK, I found a bunch of them on eBay. I swear I looked before, but it's probably been a year or more. I missed them or something.

I think your logic on cost vs. reliability and experimentability are good.

OK! wow, that's boost! Haha that much would scare me and break all the scrawny old stuff in my driveline!


My biggest design constraint is, I really want to do draw-through. I assume most modern turbos, want to pump air only, not fuel+air and don't have the seals for it. I don't see this mentioned any more. New stuff is of course EFI, and everyone here seems to be doing pressurized carbs and compensated fuel pumps, but I know myself, the added complexity and uncertainty in that will take all the fun out of it for me, and for the small gain i'm looking for, 4 - 6 lbs, drawthrough should be fine.

The gains shouldn't tax the rest of the system (T-96 overdrive trans, 8" clutch, uncertain head sealing), fuel pump (double-acting; i've got vacuum wipers), carb. Flow-wise, that also won't overtax the carb that is for many reasons perfect for this engine.


I'm not ever gonna drag race. Besides putt-putt to work, I plan on doing more "canyon driving" with the vintage endurance crowd. Balanced overall performance and pleasure in engineering to get there is the goal I've done lots of suspension work, and there will be more.

Yep, draw through needs a carbon seal.

I have an old draw through setup off a 440 that was In a motor home, but that's a bit large for you.

If you could get one of the Buick setups with the TO3 (IIRC the others were rotomasters) and try a smaller turbine housing, you might get usefull boost.

IIRC Hot Rod had an article on a father and son that had turboed their small block in a vintage camaro, they said they were paying a couple hundred bucks for the turbos, they were supposed to be for an implement of some sort.

yeah, i know drawthrough makes it tough. I'm not in a hurry. I once had a Corvair turbo (designed for a side-draft Carter) in decent shape, but i gave it to someone. oopsie. that would have been about the right size.

yeah, the one off a 440 might be a *wee* bit big!

i will look at the requirements for pressurizing the Weber, as much as I'd rather not do that.

for the record, for turbocharging on my proposed scale (around 200 hp, low boost on elderly engines, using draw-through) the VW Beetle add-ons look appropriate in size, and carbon seals are common.

this is a ways off for me, i have chassis stuff to do this year, but i'm a-lookin'

This is an interesting topic. It seems that moderation is taboo. We seem to get carried away once we start improving performance. I like where you are headed and the Stude link is great.

I started a project years ago to turbo a 292 for my '68 flatbed. My goal was to make it run here at 4 to 6 thousand feet like it would at sea level. Not a racer just a good truck. The plan was to use the turbo from an 81 firebird and the TBI from an 89 GMC. I got balled up in the Megasquirt build and learning to work in Windows so the thing is stalled. Anyway here are some PICTURES of the turbo unit. It is easily adaptable to stock inline manifolds. It was a draw through that worked well for what it was. I don't know if anyone has done a draw through with a GM TBI but it should be doable. I'll be watching this project. Thanks, Beater

ha! yeah, i get that a lot, mostly from the 'why dontcha stuck a tree fitty innit' mindset. i'm getting better at not taking on projects that will not make me happy. i used to stick to unquestioned assumptions that i now toss aside. also, 160, 180hp *probably* won't break anything. 250 will. It's fun to drive now, i like the "Twin Stick" trans (T96+OD), the dinky axle, "upgrades" to those are $$$$$$ and for what, ultimately? Weight, reduced handling, crappy gas mileage, and more off time than drive time.

Thanks for the pics! Nice carb adapter. I'm lucky -- the trough intake means in only have an exhaust mani, so no interference. Plus it goes on upside down so exh outlet points up.

Previous project was GM TBI on an AMC 232. Worked great! Hated PROM tuning! Never again. Weber 32/36 DGEVs are as fun as a carb ever was, that's the goal, that's what I'm sticking with. Carbon seals concentrate the "problem" in one spot. $500 turbo instead of a $200 turbo, but none of the attendant problems of pressurized carbs and fuel pumps, and no custom EFI which has ramifications back to the gas tank.

HA! SIDE COVERS! yours too? Just pushrods under there? Vestige of OHV conversion of an L head block?

Tom, I am also interested in a draw through [ aka "ghetto" ] turbo set up. Here is a webpage I have saved that has some useful info.

http://www.smbaker.com/rail/monsterturbovw.html

Oh, you! ha! I've already saved your page. It was very helpful to me in sorting out practical options. I was about to post 'the vw beetle nuts have worked this stuff out'. Thanks! And I'm glad you're interested in this.

I realize there are many performance downsides to drawthrough vs. blow, but they seem less onerous at low boosts (4 - 6 psi), and the system is so much simpler. (pressure-equalizing my dual-action fuel pump would be funny though -- i like my vacuum wipers. I had an EFI car with vacuum wipers too. Worked great :-)

My current thinking is to find/buy a beetle-application carbon sealed turbo. it's the most work-alike engine for my application.

Crafty orphan fans are great inspiration. I decided to go with EDIS ignition after reading a Corvair adaptation. (Hmm, what's with all the pancake motors? :-)

I would STRONGLY recommend a water cooled turbo. On one of the ACVW sites I recommended a water cooled turbo with an electric pump and a small 125cc MX radiator but the knuckleheads couldn't see the big picture. Turbo chargers are capable of having a very long service life IF they aren't overheated .

I've got an OLD trw turbo offa combine. Its the same as an old corvair but with std ends rather than with those corvair bolt patterns for carb and exhaust pipe, and its got the correct seal for draw-thru. I believe its an "F" flow .70 a/r. PM me an give me your email and I'll try to send pictures and pricing. I've had it since about 1975 and never used it.