I read somewhere after 220 horsepower, the stock 2.0 throttlebody is useless.
I have also read about upgrading to a fiero throttlebody.
1. How good is the fiero throttlebody?
2. how big?
3. What's all involved in doing this swap?
4. Is it mandatory that i upgrade my throttlebody after bolting on my t-3 60 turbo?
Sorry i searched this subject on here, and I found nothing.
Each of the TB conversion is going to take some work, none is a direct swap. By taking the Fiero throttle body, you are only gaining I think 2mm..... still not going ot be good for you past maybe 230-240hp at most. Always remember that you can only flow as much air to the head as the biggest restriction can allow. Your stock TB is a 42mm I beieve and the Fierro is 44mm (if I remember right.)
To do my swap it required a 2.3 quad 4 throttle body which has a 56mm butterfly and a 2.75" openning. You will need the TPS and idle air controller off the quad 4 TB and the harness plugs for both. The wire colors match right up to your sunbirds wiring so they are easy to splice in.
Quad 4 TB compaired to the stock (hurting) TB.
Making an aluminum flange to weld to the intake manifold. I used a drill press from home depot and a reemer bit on an air grinder to clean up the edges. After you weld the flange on you have to take the reemer and cut out the inside of hole on the actual intake manifold. I ended up enlarging the hole by about an inch.. maybe more. drill the top, left bolt hole through the manifold and tap both of the holes. You will need the Quad 4 gasket. You may also want to check for flatness after welding as well. You can set up a nice throttle linkage with the stock bracket and cable by using a dremel to cut a nice slit for the stock stopper on the cable to sit in. You are also going to need to change around A LOT of the vacuum line routing. I can make a diagram of how mine is routed if you want to do this swap.
Finished product.... the TB tilts to the left a slight bit so that the right bolt hole has clearance without eating through the intake manifold wall. You don't have to do this.. you can move the flange over further left.
Enjoy.
Cardomain|
Myspace
^^^ as a note as I didn't see it mentioned.. you can't do a swap like Minion and expect the hood to close. I'm fairly certain GM subcontracted Holley to make our fuel rail and T/B just because of how difficult it was to fit a T/B in the space they alloted.
My current plan is to run twin throttle bodies or run an oval one.. I want to retain the stock hood.
Quote:
^^^ as a note as I didn't see it mentioned.. you can't do a swap like Minion and expect the hood to close. I'm fairly certain GM subcontracted Holley to make our fuel rail and T/B just because of how difficult it was to fit a T/B in the space they alloted.
Yeah i planned on closing the stock hood. he he
Thats great information...and yes i was wondering about the vacuum lines, although i have a digram that shows where they lead.
Nice pictures also.!!!
Hmmm oval......sounds like im going to be on a search now.
I'll let you all know if i find anything that can possibly work for a bigger throttle body.
I did the Fiero swap last year. It's a bit involved but if you're mechanically inclined and have a decent amount of tools you can do it. The Fiero TB is 54 MM while the turbo Sunbird is 43 MM. I did a write up with pics of the swap and it's on Darkmuck's site WWW.lt3engine.tk.
Some guys use the 2.0 MPFI 46 MM throttle body and intake, a friend of mine has it on his car. After doing the Fiero conversion if I had to do it again I'd use the Fiero TB with the MPFI intake and get the benefit of the larger TB with a lot less work. The Fiero TB and the MPFI TB are way closer in external size and shape than the turbo TB is. My hood closed fine with the Fiero TB on the stock intake and my friend's hood closes fine with his MPFI setup too.
If you read Corky Bell's Turbocharger book and apply his formula to our engine and throttle body you'll see that mathematically the 43 MM TB becomes a restriction at the 210 HP level. I went 13.61 at 97 with the stock TB at 17 psi. That equates to 235 HP by the fairly conservative formula I use so go figure. I'd imagine the MPFI or Fiero would suffice for most set ups. If I remember correctly you need 60 MM at around 20 lbs of boost to support 300+ horsepower.
Tony
Tony
1987 Sunbird GT turbo convert
Ported intake, Fiero 53 MM TB, 52 lb inj, ported and flowed head, tube header, Mitsu TD06, ARP rod
bolts/head studs, adj cam sprocket, 4" x 12" x 31" FMIC, Paxton AFPR, modified 125 trans/LSD
unit/3.42's, custom chip tuning, Alky Control Methanol injection
13.61 ET at 101.44 mph, 262 WHP/350WTQ
2009 Pontiac Solstice GXP roadster, 2.0 turbo w/GMPP exh, CAI and turbo upgrade, 290 hp/325 ft lbs
1969 Olds 442 convert
400 Eng, 200-4R trans, 3.73 posi, power everything, OAI
How much difference is there between the flow on the turbo manifold and the MPFI manifold? Do you have any pics of the ports?
For all intents and purposes they're identical. At least performance wise. Except for the size of the TB hole of course!
Tony
Tony
1987 Sunbird GT turbo convert
Ported intake, Fiero 53 MM TB, 52 lb inj, ported and flowed head, tube header, Mitsu TD06, ARP rod
bolts/head studs, adj cam sprocket, 4" x 12" x 31" FMIC, Paxton AFPR, modified 125 trans/LSD
unit/3.42's, custom chip tuning, Alky Control Methanol injection
13.61 ET at 101.44 mph, 262 WHP/350WTQ
2009 Pontiac Solstice GXP roadster, 2.0 turbo w/GMPP exh, CAI and turbo upgrade, 290 hp/325 ft lbs
1969 Olds 442 convert
400 Eng, 200-4R trans, 3.73 posi, power everything, OAI
I believe the turbo engine was built from a prototype. It was a fairly limited production powerplant which GM never planned to sell in large quantities. So they never invested in the tooling to mass produce the fuel rail, TB, regulator, &etcetera. The 93+ mpfi engine eas sold in the US as well as other countries which may explain the more "mass produced" look which it shares with other GM engines. The TB bore centerline for the MPFI intake is higher in the plenum which makes installing an even larger TB much easier.
There are a few gotcha's with using the mpfi intake. Nothing really big. The first thing is that it doesn't say "turbo." If you can get over that, the rest is easy. The fuel rail inlet and outlet are reversed from the turbo manifold. If you're junkyard shopping, try to get the fuel lines from the manifold to the junction point under the car. There are bosses under the turbo manifold for the EGR solenoid which are moved on the MPFI intake. The fuel pressure regulator is different. It's a GM part instead of that strange ford style part that's on the turbo engine. The throttle and cruise cable ends are different on the mpfi car but the TB can be modified if desired. The IAC connectors are different and the MPFI tb has coolant passages to circulate coolant for improved emissions. There's no location for the IAT sensor and there's one or two vacuum ports which are missing. By comparing the two manifolds side by side, most of the differences can be identified before the new part is installed.
I'm at 17 psi with stock turbo and slightly larger TB. The turbo is really at it's limit right now. The TB is not yet the limiting factor. This is easy to check, really. Install the boost gauge before, then after the TB and take readings. Anything below 1 psi difference in readings is reasonable, anything above 2 psi should cause thought about a less restrictive TB.
-->Slow
