my turbocharged 3.1 V6/5-speed Cutlass Supreme sedan

[malibuolds]

this is my '91 Cutlass Supreme. i've owned this car since April 2000. i've done a ton of work to it since then. it used to have a column shifted automatic transmission & bench seats but i swapped in a Getrag 5-speed in the fall of '01 (wayyyy more fun to drive now!). i had to ditch the front bench seat so i could fit an '89 Grand Prix 5-speed center console in. it now has leather bucket seats from a '90 Cutlass Supreme International Series sedan. i added HUD (heads up display) so the speedo, turn signals etc are now projected onto the windshield. i also added DIC (driver information center) but i have yet to wire it up. that about covers it for the interior; i don't even have a stereo in the car at the moment. most of my work has to do with the suspension. when i bought it it had 14" steel wheels, but now it sports 16x8 crosslace wheels from a '94 Grand Prix GTP with 225/60 tires. the rear brakes have been upgraded to bigger 11" '94+ style W-body solid disc brakes and i'm about to upgrade to bigger 11.25" '95+ W-body front brakes. the front springs are 1.5" drop Eibach, but i have a set of 1.8" drop Intrax springs waiting to go in. the rear suspension previously used a transverse monoleaf, but it has since been replaced with an adjustable coilover kit from TDC with KYB struts. i can slam the rear of the car or raise it about 2" above stock height by turning the lower spring mount on it's sleeve (see pic). other than that i have a big 22mm Addco rear sway bar and a 34mm front sway bar sitting in my garage waiting to go on.

the main upgrade however, is the engine. i got lucky and found an extremely rare '90 Grand Prix ASC/McLaren Turbo STE in the local salvage yard with the 3.1L Turbo engine. i brought the engine home and decided to replace the head gaskets, but i found a melted piston! ****! so i decided to throw all of the turbo specific parts onto my original NA 3.1 MPFI engine (it has the same CR). i am confident that this car will walk my T2 GTS no problem with 10psi. right now i am only running 4-5psi. my "boost controller" is simply a vacuum line from the fitting on the compressor outlet to the wastegate can. i will add a grainger valve MBC to the car soon and have it adjusted to 10psi. i do have a custom burnt EEPROM in the ECM which allows for 14.5psi before BFC, but i'm afraid the little Garrett T-25 i'm using gets very inneficient above 10psi.

[malibuolds]

oh, i posted this thread again because i think my original thread had been trimmed from the database. iTurbo (my brother) and myself got some vids today of the car, and i thought i would post them up. iTurbo is driving and i have the camera:

launch:
http://www.turbosedan.com/vids/MOV02268.MPG

mild burnout:

http://www.turbosedan.com/vids/MOV02270.MPG

that is only 4psi, i'm sure it will be much quicker with the g-valve at 10psi

thanks for lookin'
-------------------------
Joshua Mitchell
'89 Lebaron GTS - T2/A555
'91 Cutlass Supreme sedan - 3.1 Intercooled Turbo/Getrag 282 5-speed
'94 Bonneville SSE - 3800 SI/HM-4T60E

[Ondonti]

I would love pics of the exhaust manifolding........

[malibuolds]

the TGP rear exhaust manifold is a mirror image of the front exhaust manifold. of course, there is no dump in the rear manifold like a NA 3.1 engine has. the crossover pipe has had new SS flex bellows welded in. stock TGP downpipe.

here are some pics that better show the exhaust parts:

http://www.turbosedan.com/cutlass/engine/DSC01608.JPG
http://www.turbosedan.com/cutlass/engine/DSC01610.JPG
http://www.turbosedan.com/cutlass/engine/DSC01612.JPG
http://www.turbosedan.com/cutlass/engine/DSC01616.JPG
http://www.turbosedan.com/cutlass/engine/DSC01617.JPG
http://www.turbosedan.com/cutlass/engine/DSC01618.JPG
http://www.turbosedan.com/cutlass/engine/DSC01621.JPG

i took these pics when the engine was still on the stand. i just wanted to mock everything up so i could make sure everything fit ok.
-------------------------
Joshua Mitchell
'89 Lebaron GTS - T2/A555
'91 Cutlass Supreme sedan - 3.1 Intercooled Turbo/Getrag 282 5-speed
'94 Bonneville SSE - 3800 SI/HM-4T60E

[Heavytank2]

Oh my god... you HAVE to post vids when you get it running 10 psi.

I had a Grand Prix (95') that I dreamt of modding before... this is so along the same lines as what I wanted to accomplish. Although yours was in crate form if you think about it...


Keep us updated! I might just get inspired to make my own.

[Ondonti]

Manifolds look about the same as the prototype 3.0 manifolds. Basically a mirror of the front 3.0.

Do you have a bracket holding up the turbo ?

My welding was just completed for my own v6 setup. Gotta wait till august though.

[malibuolds]

Quote:

Originally Posted by Ondonti Do you have a bracket holding up the turbo ?

yeah i had to get a bracket custom made. the turbo support bracket on the TGPs is part of the transmission shield/mount thing. since all Turbo Grand Prixs have automatic transmissions and i'm using a 5-speed, there was no way i could have used it. i had a local welding/fabrication shop make one for me out of stainless steel for $40. thankfully there just happened to be two holes that were already drilled and tapped on top of the transmission. the bottom of the bracket bolts to those two holes, and the top of the bracket bolts to the turbo flange on the crossover pipe:

http://www.turbosedan.com/cutlass/engine/DSC01873.JPG
http://www.turbosedan.com/cutlass/engine/DSC01875.JPG
http://www.turbosedan.com/cutlass/engine/DSC01876.JPG
http://www.turbosedan.com/cutlass/engine/DSC01878.JPG
http://www.turbosedan.com/cutlass/engine/DSC01879.JPG

turbo support bracket installed:

http://www.turbosedan.com/cutlass/engine/DSC01885.JPG
http://www.turbosedan.com/cutlass/engine/DSC01886.JPG

i'd like to see your 3.0L turbo project. 3.0 SOHC Turbo would be nice
-------------------------
Joshua Mitchell
'89 Lebaron GTS - T2/A555
'91 Cutlass Supreme sedan - 3.1 Intercooled Turbo/Getrag 282 5-speed
'94 Bonneville SSE - 3800 SI/HM-4T60E

[turbovanman]

Is that turbo crossover stock?

[malibuolds]

Quote:

Originally Posted by turbovanman Is that turbo crossover stock?

yup, except for the SS flex bellows. the original flex bellows were cracked so i had them cut out and newer (much much better) SS flex bellows welded in. it used to have a heat shield too, but that does not fit with the new flex bellows. i would like to someday have another crossover pipe made with a T3 flange so i can get rid of this little T25.
-------------------------
Joshua Mitchell
'89 Lebaron GTS - T2/A555
'91 Cutlass Supreme sedan - 3.1 Intercooled Turbo/Getrag 282 5-speed
'94 Bonneville SSE - 3800 SI/HM-4T60E

[iTurbo]

Wow talk about a fun car to drive! It seems so much easier to launch than our TDs.

If I upgrade my Spirit R/T's turbocharger, you're free to have R/T's original turbocharger. It's got to be better than that T25 on there. ATP has most of the parts needed to adapt it to your setup.

[Ondonti]

I need to get some decent finished pictures.

[89acclaim]

I wonder how well a Holset would work on that..... hummmm

Daniel Merrill

[ThreeTurbos]

some type of grand prix turbo car in my local yard.

been eyeing it for sometime.

i owned an 87 z24 (gen1) 2.8mpfi 5 spd getrag with a 3.1 swap in it. with no turbo this car FLEW!!!


thats pretty cool what u have done with that car, props where due.

they are due here.

nice job.

[xtrempickup]

look, a car with a timing chain, no belt to skip or break or shear teeth off, thats a major plus also

[malibuolds]

Quote:

Originally Posted by xtrempickup look, a car with a timing chain, no belt to skip or break or shear teeth off, thats a major plus also

funny you mention the timing chain i thought i had actually "finished" the Turbo Cutlass project last May. well i drove the car 4 blocks (literally) and the timing chain broke! turns out i bent two valves, and 3 of the pistons had very very slight marks where the valves had kissed the pistons. so i spent most of June tearing the top half of the engine apart. sent the heads to the machine shop to replace the two bent valves and another valve job for those two valves, replaced the timing chain, had to buy a bunch of gaskets and new head bolts again. that was a real pisser!

i should admit that this was a VERY low budget turbo project. like i said in my first post, i turbocharged a previously naturally aspirated 3.1 MPFI engine. i did not mention however, that said engine has 227,000 miles the shortblock received a new Melling HV oil pump and that was it (besides cleaning the holy heck out of EVERYTHING). the engine ran great when it was NA, and it was fairly clean inside despite the high mileage. it got a new timing chain set only after the first chain broke. i did use TGP heads, which were hot tanked and bead blasted, very slightly resurfaced, new expansion plugs, 3-angle valve job and new valve seals.

i do have the "real" TGP shortblock sitting in my garage on an engine stand right now. due to that engine having a melted piston however, it needs a complete rebuild with .020 over pistons.

turbocharging this previously NA 3.1 engine was somewhat of a crash course in learning the TGP setup. i will have fun blowing it up while i rebuild the real TGP engine
-------------------------
Joshua Mitchell
'89 Lebaron GTS - T2/A555
'91 Cutlass Supreme sedan - 3.1 Intercooled Turbo/Getrag 282 5-speed
'94 Bonneville SSE - 3800 SI/HM-4T60E