Turbocharging 40 years ago

[Aircooled]

Some things to ponder
1. Name an OEM turbo engine that uses a blow through carb.
2. Turbos used in draw-through applications must have a compressor side carbon shaft seal. Since this seal in not needed in Diesel or EFI applications very few modern turbos have one.

[STINEY]

Alpha Delta and Lotus Esprit. Blow through Dellortos

[Dynoroom]

I ran many draw-thru turbos systems. Worked great on boats because throttle response in a pleasure boat wasn't a big deal. If you look at the SCTA record book you'll see a D/BGMS record set in 1988 @ 242 mph that is STILL a standing record. 305" ci. twin turbo, intercooled, twin carb draw thru. EFI really didn't happen for almost another 10 years. I always hear about mixture issues or puddling due to intercooler use, never had any of those issues. I ran Fel-Pro 1003 head gaskets at the time, no o-rings in the block 18/20 lbs. boost. I know it won't work & you can't do it this way so we did.......... for about 10 years. The car now has EFI. Oh, it also ran a blow thru system for 2 seasons before going to draw thru, what a POS THAT was.
Aircooled is right regarding the carbon face seal but I think Garrett still makes a T-4 turbo with a carbon seal. That limits the total power to ~ 1200/1400 hp. We used Rajay turbos on the corvette that set the record.
Here are some pictures of the engine & car.

[Dynoroom]

Here is a picture of the blow thru system used on a 427" big block. It also set a record at the time (1980) @ 240 mph. It was a lot more trouble than the draw thru which ended up going faster in the end.

[dieselgeek]

Wow! that was awesome. Mike did you tune these by feel / plugs / EGTs / ?? back in the late 80s, early 90s?

[Barry Donovan]

Alpha Delta and Lotus Esprit. Blow through Dellortos

bmw, porsche, vw..
they all did something with that solex something.
terrible.
Subaru had turbos in the 70s.. looked very much like a spaghetti carb, but had help narrowband (worthless).

I have yet to decipher the rochester myth, that they are all designed to be blow thru or draw through..no directions.

it is funny, I am about measuring things more than gaining controls...
the subaru ea series can variate 24hg to 8hg..all one engine through a maine season.

narrowband as an aid is hilarious. (I owned just one - they did away with it in a hurry)

this thread and that porsche story I shared.
it was the middle 80s, we were taking the route that stays outside of the big apple (I-84?)..
always quiet out there. We had a load of that blue styrofaom at nearly 15feet tall. Smacked a bridge and left a trail of little blue chunks miles long.

we are on the side of the road and heard a most peculiar sound..the flat six is easy to identify, and we both knew it wasn't...we did identify boxer and round lights coming...
it went by smacked off the road, blue foam flying, sparks, ....and it was four cyls with a turbo.

I have been in awe ever since. Even the japanese stuff. The boxer takes the cake, always will.
you could smell the fuel, as if it was just dumping a home mad something....boxer don't care.

I looked for a new york related porsche, possibly brown..plain body. did find a few..just waiting to see what little clan of rich backyarders that was to speak up.

Around that time, I could guess the RUF legend was really begin to flying.

[TheSilverBuick]

Mike rules!

[blownhemi]

I've tried both and all they did was reaffirm my belief that you can't beat EFI when it comes to turbo. I ran the draw through first with a Rajay and it was okay with good throttle response and easy setup, but the blow through with an intercooler setup was much more fun. But heat soak in the carby was a major issue with the inline Hemi six (245ci). Eventually I ditched both setups and now run a 300hp (265ci) inline six in my Valiant wagon. No heat issues now, and similar power. But EFI would have been the way to go. For a time I ran a single turbo 231ci Buick V6 with EFI and it made an easy 450hp. Enough to push my 3200lb sedan to an 11.99.

[Huskinhano]

I probably still have that issue...Damn I feel old now...

Me too.

[Dynoroom]

Thanks Scott & Randall. See you two at SEMA?
Scott, we tuned just like everyone else did back then. Read the plugs, make a change, did it go faster or slower.
EFI indeed made turbocharging something almost anyone could deal with. Big power at the touch of the keyboard. Who would have thought?.......

[Dynoroom]

Speaking of tuning before electronics; I remember putting a knock sensor on the dyno & the lights would go nuts just reving the engine. I still have an early 1 wire O2 sensor that was so fast at gathering readings I went outside to check my sun dial then went ahead and read the BSFC, Sooner or later it would show a trend..........

[TheSilverBuick]

Your experiences and thoughts are always enlightening! Data lag worthy of a sun dial


Unfortunately I'm working Monday through Thursday, but I am heading to southern California Thursday night (Nov. 6). If there is going to be a get together of some kind Thursday night I'll stop and stay the night in Vegas. I'm easily found here or DG has my number.