I haven't personally done one, but from what I've heard, while it makes the fuel system easier to build (more like a roots blower setup) it is more dangerous because all the piping post-turbo is filled with hot, compressed air and fuel. One little sneeze and pop goes the weasel. I suppose if someone did one in close proximity to the intake, the effect would be of less volatility.
A sheet metal intake with the turbo right where the carburetor would be. Kinda how a 7.3 power stroke is setup. I'm just kicking around ideas but you cant get the turbo any closer them that. What's your take on the idea?
If there's room to do it like that I'd try it! I don't see it being any worse than all the draw through blowers that have been around forever. Talk about something unique at a car show!
That was my first thought way back when, but I went straight to efi instead. I had planned to use 2 draw through setups on an offy 2x4 intake. (231 times 2 = 462) May not be the latest and greatest way to do it, but at 8psi boost it would still be a hoot!
I had considered that in an offhand sort of way. The turbo trans am and buick 6 turbo setups can be had on ebay from time to time. I was considering hogging out what I could from the plenum etc and joining it to a custom spacer off a stock manifold. what stopped me from trying it was needing a larger turbo to power a v8 and trying to figure how to get one to fit the original plenum etc. I am sure it could be done. Id love to see it. cowl hood scoop would give plenty of clearance up top. ---------- Post added at 06:39 PM ---------- Previous post was at 06:36 PM ---------- that is a really cool idea ---------- Post added at 06:39 PM ---------- Previous post was at 06:39 PM ---------- that is a really cool idea
Sounds like a plan but what kind of a cam would I need to run? Would a 3000 stall converter be loose enough? I already have 373s. I'm picking up a 78 service manual on eBay so I can learn more strait from the cows mouth. And last but not least. Timing.......why does timming scare me so.....mechanical and vacuum??? I know nothing about timing. Oh and I read some where that I need to get a turbo within positive seals so the oil doesn't get sucked out when I would let up off the throttle. Who makes them?
draw through turbos have been around for some time, as others have said. i'm not sure what gramps ran, but the ole man called it a studebaker with a supercharger and ride control snubbers, and a ford doin' 80 couldn't keep up to that thing doin' 50. erskine was the name of the car i'm sure, but it was so long ago. anyways, what i want to discuss is my plan for my regal t-type. it's an 83, with o/d, 4bbl, a/c, t-tops and a bench seat. i really like what i se/read about the powerjection iii units, yet don't know anybody personally who runs one. for my drawthroughapplication, something like that would be extremely userfriendly, smooth and reliable, for anyone who likes to jaunt around from sea-level to 4800'. other goodies would be a msd6al-2a boost retarder, pertronix ignitor, and maybe one of those boost pressure trickers. if anyone else is contemplating this, or has accomplished a similar build, please chime in...
my t-type came back from a repair missing its dual can distributor... a dual canister(vaccum/boost) unit is used to adjust timing under various conditions. a boost retard unit essentially is used inline between the ignition timing event calculator(points/trigger...) and the coil. a 6al-2a is somewhat programmable as you can set the amount of retard expressed in degrees, for a given amount of boost expressed in p.s.i.. i had some great times in the past few days troubleshooting my winter ride overthinking what three components have been doing for over a century with respect to the internal combustion engine. i.e. air-fuel-spark. obdii scan box said there was a misfire in cylinder two of my f%^$ 4.6 p71. after changing out an ignition coil, swappping it from cyl to cyl, i decided to try diagnosing the old fashion way by removing spark from each cylinder one at a time to find the misfit that made a "pup pup pup pup" note in my exhaust tune. it turns out i racked my brain for some time until i discovered i had TWO faulty plugs on one side of my engine. the solid state equipment today simply does to the modern engine what mechanical devices did in the past without friction and mechanical contact. so to set up a distributor differently? hmmmm.... yes and no. for the no boost/load/idle portion of the event timing is the no portion. yes portion of the answer is in respect to what happens after throttle tip-in.... i-e. forced acceleration, boost lag, rpm when boost begins, how much taper required in boost retard curve......... so engines have been doing the same thing for years, the mechanics of this work is all that has changed. if anyone else following this knows of some recurving required in my information, please feel free to add.
The 62 Olds Jetfire draw thru (215 aluminum) had a turbo output bolted directly to where a carb would go. The single barrel side draft carb went directly on the turbo input. No safety issues there. But boost was limited to 7 lb, no chance for an intercooler. Bruce Roe
The biggest problem you'll run into with a draw-through setup from a performance point of view is throttle response. The farther your throttle is from your intake valves, the slower your throttle response generally is. When you couple that delay with needing to spool up the turbo, you might have over a second delay from the time you floor it to the time you actually get boost. Tuning it will also be a problem because when you floor it you won't get the accompanying rush of air into the engine as the carb squirts all that fuel in, thanks to the delayed throttle response. You'll run rich a lot of the time street driving as a result, I'm guessing. It'll probably idle fine and run fine wide-open, but anywhere in the middle it'll take a lot of tuning to get your fuel right. Draw-thru setups work well with Roots-type and Whipple-style blowers because there's a very linear, predictable relationship between RPM and air volume with a positive displacement supercharger. They're less successful with Procharger-style superchargers because the relationship isn't quite so linear, it's more logarithmic. They'd be least successful with a turbo setup for much the same reason. ---------- Post added at 11:33 AM ---------- Previous post was at 11:33 AM ---------- The biggest problem you'll run into with a draw-through setup from a performance point of view is throttle response. The farther your throttle is from your intake valves, the slower your throttle response generally is. When you couple that delay with needing to spool up the turbo, you might have over a second delay from the time you floor it to the time you actually get boost. Tuning it will also be a problem because when you floor it you won't get the accompanying rush of air into the engine as the carb squirts all that fuel in, thanks to the delayed throttle response. You'll run rich a lot of the time street driving as a result, I'm guessing. It'll probably idle fine and run fine wide-open, but anywhere in the middle it'll take a lot of tuning to get your fuel right. Draw-thru setups work well with Roots-type and Whipple-style blowers because there's a very linear, predictable relationship between RPM and air volume with a positive displacement supercharger. They're less successful with Procharger-style superchargers because the relationship isn't quite so linear, it's more logarithmic. They'd be least successful with a turbo setup for much the same reason.
Wow I never thought of all that yet. I'll have to do more research into everything. It doesn't sound like that good of an idea anymore.
Might be better off with a box around the carb and a blow-through setup? Oh, and another huge factor to consider is the size of your turbo. You can reduce your turbo lag significantly by sizing your turbo correctly to your application, and if you went a little undersized it would spool up faster. I remember reading a review of one of the later-year-model turbo'd VW's and they were talking about how it had great throttle response on the low end for a turbo, but that it kind of wheezed out at the high end because the smaller turbo had given about all the boost it could a bit below the redline. If you wanted something with a lot of low-down grunt, you could achieve the same thing pretty easily with using a smaller turbo on a BBB, even with a draw-through setup I'd imagine. Now, you will have to learn how to read a compressor map of course to pick absolutely the right one... But you can probably get away with just doing some bar napkin math to estimate it. If you figure that a 455 is about 7.6L of displacement, then a couple of stock turbos for a GN (2 that each worked pretty well on a 3.8L motor) would probably be OK on an application that's similarly EFI'd and computer controlled. If you wanted to get them to spool faster because you're doing a draw-through and don't want a lot of boost anyway, go a little smaller on the turbos. A pair of T3's (like from a Mitsu Eclipse/ Eagle Talon) might be too small because they're designed for good operation on a 2.0L motor, so you'd maybe want something sized between a GN stock turbo and a T3. Find some guy selling his used turbo kit off a 5.0 Mustang, maybe.
Oops, my mistake. ou: Then, for cheap and widely available junkyard turbos, a pair of stock T3's would probably be just about perfect for the low boost, lower RPM, budget application you're talking about. You can find loads of info on how to rebuild your own cheaply, too. Here's an example: http://www.youtube.com/watch?v=I2CwBwrdnvA If you're looking for new, here's another handy selection guide: http://www.turbobygarrett.com/turbobygarrett/turbochargers Here's a different, brand independent guide to different turbos by sizes. It's not exhaustive by any means, but it makes for interesting reading: http://www.ztechz.net/id1.html ---------- Post added at 10:20 AM ---------- Previous post was at 10:20 AM ---------- Oops, my mistake. ou: Then, for cheap and widely available junkyard turbos, a pair of stock T3's would probably be just about perfect for the low boost, lower RPM, budget application you're talking about. You can find loads of info on how to rebuild your own cheaply, too. Here's an example: http://www.youtube.com/watch?v=I2CwBwrdnvA If you're looking for new, here's another handy selection guide: http://www.turbobygarrett.com/turbobygarrett/turbochargers Here's a different, brand independent guide to different turbos by sizes. It's not exhaustive by any means, but it makes for interesting reading: http://www.ztechz.net/id1.html
squires turbo systems makes some really nice kits for turbocharging... sean and freester are both correct, you are as well. run what ya brung! i learned a lot from a tradeschool teacher in thunder bay, who used to say "don't let fear and common sense get in your way"... a remote turbo system a la "sts" may well be what your speed doctor ordered, if, IF you prefer not to buy a kit for mounting turbos in your engine compartment. mounting turbos in the engine compartment on ready-made manifolds will really cut down on shop and fabbing time. pay now, or pay later. your choice! everyone who has a system that runs well will swear by it. my current summer car has a 327 with performer rv cam, 700r4 with 3.08 gears. it is certainly not the fastest car around, or the nicest one at a&w cruise nights in calgary, edmonton, fort macmurray, kelowna, campbell river, timmins or sudbury... heck! i even took it to port dover on one particular friday 13th... it's my car, AND, just as i suspected when i put it together like it is, 5 years ago, it is still an absolute blast to drive today. i usually burn 4-5 tanks of fuel on a good burn, so 0-60 is not a priority. years ago, i ran a 350 buick in a 75 skylark with buckets, floor shift and a/c. it was a really fun car to drive around, and a lot of people said they haven't seen a nova quite like it... i would just smile. what can one say to that. have fun man! it's your ride. a lot of research will take you far, especially once your knuckles are wratched, and your wallet is empty... ---------- Post added at 05:46 PM ---------- Previous post was at 05:21 PM ---------- having said that... it will be just a little while 'til i can get back home to get my heads out of the lordco depot, along with the camshaft i had ground... i will post the final specs on them as soon as i see them. it will be a lot of fun to affix those rehabbed heads and cam into the 455 sitting in my avatar. it would also be nice to drive home(3-4 tanks of fuel from where it is...) in my t-type once the ignition and induction woes have been sorted. i do intend to keep the current draw-through set-up on it, but with powerjection iii, and an msd 6al-2a ignition tricker. that motor was refreshed within 8000 miles, but was put together wrong after "losing" (it's just what i'll call it) the correct feedback rochester q-jet, and dual can distributor.(let's just say that someone needed them more than i) have fun no matter what.
