So, here we go. Let's keep the stock air cleaner assemly. Remove the filter. At the pipe sticking out on the driver's side, remove the plastic hosing running to the front of the car. In it's place, put the hosing running from the turbo. To me, that doesn't seem a whole lot different than the way the turbo TPI's are set up. Everything else should still work the same. And if you've got a dual snorkel, twin turbo's should be pretty easy. You'd have to seal off the air filter assembly pretty well to keep the pressure, but that shouldn't be that difficult. You could probably even modify the thermac valves to be the wastegates.

------------------
89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else

 

stock air cleaner is very restritive and too flimsy for forced induction.

------------------
-Tas
'89 Formula WS-6

305, TBI, 700R4, P.A.W. 14x3 open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips, Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248)
Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options

 

Turbo charging has a bunch more things to consider. As JPreovst will probbally point out you are going to need more fuel pressure. then you have to think about fuel enrichment with X ammount of boost and getting a 2 or 3 bar map and probbally a different computer. Now you have to get a set of turbo manifolds, and then get the turbos, and then plumb some exhuast to them.
Now you have to run oil to the turbo (s) and return to the pan. And now you can start to think about plumbing intake ducting to the TB.
Since I have a huge engine compartment, and have TBI, and also have an unlimited source of turbos, I have often considered this for myself. I have a perfect garret t3 that I am waiting on finding a match for, and this project will begin on my car. I will probbally use one of those aftermarket dual snorkles, or I might have to call up a company that sells forced infuction stuff and get something.

------------------
69 Chevelle 2dr hardtop blue, bench seats, 12 bolt w/3.73's muncie 4 speed. TBI w/custom harness and prom best 14.5@90

 

Will the air cleaner housing really handle any boost? I would think it would have to be a one piece unit. Then sealed off better to the TB. I dunno how the carburated units work, but it seems like to me that the air cleaner assembly could not hanle much boost before it would warp and release boost.

[This message has been edited by Kyle F (edited November 12, 2001).]

 

for some reason budget twin turbo **rd guy bought k&n carb bonnet for the project, even it was the most expensive part (99$)
http://www.geocities.com/MotorCity/D...668/tt351W.htm

anyway having TBI turbo project, smallest issues will be how to route pipe from turbo to TB.


-P (just opinion not expertise)

 

I built a custom air-box to replace the stock air-cleaner in my supercharged Cross-Fire:

http://w1.601.telia.com/~u60113742/air_box/air_box.htm

and the finished result:

http://w1.601.telia.com/~u60113742/m...e/my_vette.htm










------------------
Jonas Bylund


[This message has been edited by JoBy (edited November 11, 2001).]

 

Yeah, the intake part is pale in comparison to getting the TBI to deliver enough fuel. I don't know how Joby did it but I'm sure he's done something more than the obvious.
I would like to see a turbo TBI, aren't many if any that I know of. Joby is supercharge so I guess that doesn't count but in theory he's done the hardest part.
I think the stock intake would probably hold but you're right, there would be some flexing and a flux of boast pressure because of it. That wouldn't be fun to tune around!
Life is simple, TBI is simple, only down side is the actual wet flow system. Joby did it but I'd like to know more about how he did it. A dry flow doesn't have the problems of fuel being injected into the pressurized air and then flowing through some more runners. It would be difficult to just get a nice atomization of the fuel with constant pressure and even more changes in pressure when the TB blades snap open!
I'm no expert, heck, I've never played a part in tuning a power adder...yet, but I would believe an easy fix to the fuel delivery problem would be:
Large injectors, screens on the intake gasket to reatomize the fuel for better gas milage/idle quality, custom eprom, stronger leak proof intake, and a friend with a wide band o2 sensor to nail the eprom thing fast. Oh yeah, and a 2 bar map sensor at least.
See...not as easy as a bolt on

 

i would suggest a new air box, not because of the weakness or restriction of it, but just because by the time you went around and sealed every hole and rewelded the whoel thing you could have made a better one.

later
tim

------------------
91 Camaro RS-LO3,Auto
New Times Coming Soon!
Check Out The East Coast F-Body Nationals Home Page
www.geocities.com/njspeeder
My MAFB.ORG Home Page
www.mycar.net/mafb/registry/detail.cfm?id=299
DSI Racing Home Page
www.geocities.com/foff667

 

Actually it worked much better than expected.

The engine is compleatly stock. I have not even removed the valve covers yet.

Mods before supercharger:
* ADS Super chip with low temp thermostat
* EGR removed
* Cat removed
* AIR-pump removed
* New dual exhaust with headers and X-Pipe

Mods to make the supercharger work (exept for plumbing and mounting brackets)
* Vortech supercharger
* 1992 (LT1) Corvette fuel pump.
* Dump valve
* Progressive 2:1 fuel pressure regulator

I 'just' bolted everything together and it worked great. Measured 300 rwhp (65% increase).

According to my G-Tech:
0-60 MPH 4.7 sek.
1/4 Mile 12.73 sek 116.3MPH.

All this is with Stock ECM and NO tuning what so ever. At WOT I am running way rich.

------------------
Jonas Bylund


[This message has been edited by JoBy (edited November 12, 2001).]

 

Well if you don't include installing a fuel pressure regulator tuning...then no you didn't. Since I doubt you disabled EGR in the ecm, you probably installed a check valve yes/no? If so, then the ecm is advancing the timing thinking EGR is working. Problem with this...kind of. Running too much base timing and no EGR and ecm advancing thinking EGR....knock knockin on heavens door...sorry, went off on a solo there. Good you're at least running rich under WOT, wouldn't want it the other way, lol or we probably wouldn't have had the winaldl software .
How's your gas milage?

 

I have an ADS superhip and I think that the EGR is disabled in that.

I am still using the stock fuel pressure regulator at stock pressure. When I get boost the extra regulator takes over and raises the fuel pressure.

When I have manifold vaccum the stock regulator regulates the fuel pressure to 12 psi over air-box pressure (before throttles). When I get positive manifold air pressure the external progressive regulator takes over. At 5 psi boost the fuel pressure is 17 psi over manifold air pressure (after throttles). At 10 psi boost (max boost) the fuel pressure is 22 psi over manifold air pressure.

If I look at a fuel pressure gauge it reads 32 psi over atmospheric pressure at 10 psi boost. Fuel pressure over manifold pressure (22) + manifold pressure (10) = 32.

At idle it is almost no air-box pressure so the fuel pressure at the pump is only 12 psi. At max boost it is 32 psi. That is why I had to replace the fuel pump.

Did I confuse you all now?

edit:
Forgot about milage ...

At a 200 mile trip this summer I got 23.5 mpg with the supercharger installed. That was conservative driving.

------------------
Jonas Bylund



[This message has been edited by JoBy (edited November 12, 2001).]

 

JoBy, what is that toward the back of the passenger side of your airbox? When I first looked at it, I thought you put twin turbos on. Or maybe a supercharger and a turbo together.

------------------
Cheston Phillips
'96 BBB Impala SS "ADIOSS" & '91 white Caprice 'n0n 9c1' w/L03

GM_TBI list = http://groups.yahoo.com/group/GM_TBI

[This message has been edited by AdioSS (edited November 17, 2001).]

 

I have been following this topic for awhile, and am thinkin this would be even better using a Garret turbo(not sure what size yet) and TBI.

I would use a little better(and taller) airbox design. possibly a carb bonnet that the Carb or TBI trucks use with their SC's.

This would go onto(eventually) on the 383 I am building. SDPC block, forged reciprocating assembly, Pro Action Iron lightning 200cc heads with 64CC combustion chamber, Lunati 268/279 advertised duration, single plane intake(not sure what kind yet, possibly weiand 7525), big TB and injectors, ADS superchip to get running, then burn my own. Aiming for 9:1 CR N/A, would this be low enough?

What do you guys think of this? I was thinkin of using a supercharger, but I hear turbos are cheaper and put out more power.

------------------
89 RS parts car
Daily driver 91 RS auto LO3 70k, 14x3 K&N Open element, cat-back delete, Richmond 3.42's, Zexel Torsion posi, Accel remote mount Super Coil.
Coming soon: 470HP 383, Hooker SC/LT headers, true dual Loudmouth exhaust, gutted cats.

 

AdioSS,

That is a dump-valve. And you hear it when let go of the trottle ...






------------------
Jonas Bylund

 

This is the way my Paxton kit was made to look like.

I'll be changing it this winter to something much more efficient.
The only question I have about JoBy's setup is that my Paxton kit came with a small plate to put under my TBI, I had to drill two small holes up through the TBI to meet the throttle shaft, and I had to run a small 1/8" boost line to the plate all in order to pressurize the shaft so no fuel leaks out the ends under boost. So I'm wondering if you completely enclosed everything including the throttle linkage or what?

Mike

------------------
Car:
92 Formula
Stock 305 TBI and 700R4 trans
Mods:
7psi Paxton
Edelbrock Coated headers, high flow cat, Flowmaster catback
SLP takeoff posi, GM 3.42's
Nitto Drag Radials (245/50/16) on ARE road racing rims (8lbs lighter each)

Best 1/4 mile - 14.421 @95.96 w/a 1.983 60'

[This message has been edited by Blown 305 TBI (edited November 19, 2001).]

 

I modified my TBI's in a similar way. I drilled two small holes from under the TBI to the throttle shaft. They are connected to engine vaccum, not boost.

The TBI's are not compleatly enclosed.

------------------
Jonas Bylund