Svante

Hi.

I´m in the middle of swithing out my 70mm in 80mm out Holset HX50 ( 28 exhaust housing ) for a more suitable unit. The goal is around 8-900hp on the street, with a quick spoolup. The Holset begins to spool around 3500rpm and gives me full boost arund 44-4500rpm. Hopefully i can reach full boost around 38-4000rpm with a more modern unit and still make the power i want.

The motor is a fully built 355ci, crankmaster crank, compstar rods, diamond ceramic coated pistons, 300+cfm 195cc trick flow cnc heads with modified holley stealth ram intake, mild comp 12-564-4 camshaft. Fuel system is Weldon 2345A fuel pump and bosch 1680cc injectors. Runing E85. Autronic SM4 ECU.

Car runs good as it is and have traction problems up to 4´th gear on semi slicks with 22psi of boost. But i dont like the turbo lag!

Any suggestions of wich turbo to go for? I had the idea of going with a single Precision CEA series like the PT6766 w, T4 divided and A/R 1 or 1.15. But maybe it will be a bit to small for this engine?

Price range i was thinking: $1000-1500.

Thanks.
/Svante.

Impala Balko

Do you have some detailed pictures of your rear mount setup, I am in the middle of building a rear-mount turbo setup for my 94 Corvette

Svante

Sure. Maybe not in detail but you can see how i did the setup ( the parts are a bit dirty from beeing used ). The turbo system basicly bolts right up the rear by some home made brackets. I have a replacement silencer that replaces the turbo when the vehicle has to be inspected every 2 years.

Anyways! I made a oil feed adapter in my lathe that moves the oil temp sensor out a bit, this way i can feed a 8mm pipe back to the turbo. The oil that drains from the turbo enters a small tank bolted on the oil return, i made this in a Cnc-mill but i can be made out of sheet metal and welded to. The tank is drained by a electronic 12v gear pump that scavenges the oil back to the engine ( to a connection in the oil pan ). The exhaust is fed through LT1 headers via a 2.5" Y-pipe that enters a 3,5" pipe on the drivers side of the tranny all the way back to the turbo. And then there´s only the wastegate and pressure pipe back to the engine. Pretty simple solution. I made a aluminum sheet metal cover who i painted with heat resistant color just to hide the turbo setup.

/Svante.

Impala Balko

Do you have more pics of how the piping is run, how big of diameter is your charge pipe where did you mount your scavenge pump... looks like a nice clean setup.

ANTI VENOM

Sweet!!! I haven't seen a big single in the back before. I like it. Can't wait to see your new numbers with a "modern" turbo. Please keep us posted...

Svante

Ok, here you have more pictures. I was taking some measures for the new turbo i ordered ( Borg Warner S400SX4-75 1.32A/R T6 Airwerks Billet ) rated 1050hp. Should be enough for this poor 355

I took some pictures of the plumbing and the scavenge pump when i was under there! ( i got to get myself a 2-post lift )..

Anyways, the chargepipe is made out of 2,5" steel tubing. Same as you build your own exhaust system of. I was planning to make it out of aluminium first but it was so expensive that it was´nt worth it. I made some brackets that is threaded in the C-beam to hold it in place. It enters the engine bay on the pass side of the engine right behind the oil dipstick. And then via a alumium tube straight forward to the intercooler. The picture shows A- Oil return ( stainless steel pipe 15mm OD ) B- Charge pipe ( 2.5" steel ) C- Exhaust ( 3" out of the flex and then 3,5" to the Turbo ).

The Scavenge pump is a gearpump with bronze internals. Made to pump diesel and water, but works fine for engine oil. As long as it gets some oil to lubricate itself from time to time it does´nt seem to bother.

There´s not much more to it. I took a picture of the turbo when washing the air filter. It shows the small oil tank below the turbo. The upper hoose goes to a bigger ventilated tank that collects the oil if the car is parked uphill and turned off ( All the oil still in the return line drains back and needs to go somewhere when the pump does´nt run )

I will keep you updated how the new turbo works for me. Hopefully it wont blow up my engine on the dyno and i can post a movie on the car later on.

Thanks.
/Svante.

nitrusmr2

That is awesome!

Svante

Thanks.

A litte update! The new turbo arrived a week ago, but i was on vacation so i could'nt begin working with the car until now. The new unit is a Borg Warner S400Sx4 with 75in 88out a/r 1.32.

It's a monster comparing to the Holset, but i still think it will spool quicker due to the smaller a/r.

I can post some pictures during the installation if you like.

/Svante.

nitrusmr2

That compressor housing is huge. It looks like a very well thought out installation. I like the bracket off the compressor housing to the frame. Has it ever cracked? Do you have a sort of shield under the back of the car that hides the turbo? The pic from the rear is too dark to see under there.

Aaron

Svante

The bracket is milled out of 10mm aluminium and i have never had problems with it! But the turboflange also have a bracket, so the turbo is held in front/back and from the exhaust.

I have made a big shield ( 2mm alu sheet ) that protects the package from debris etc. I painted it black to ease the curiosity a bit

If i remeber i can take a picture of it.

/Svante

ANTI VENOM

Very nice. Hopefully that will get you what you want. I'm not familiar with that turbo but it sure looks impressive. Best of luck.

Impala Balko

What kind of intercooler do you have... I am baffled as to what kind of intercooler I should buy for my rear mount build. I don't know if too small of one will cause a restriction and Rob power.

Svante

Thank you.

The turbo choise was'nt easy, but i've seen some nice numbers out of the BW SX turbos so i give it a try. Also the price is great.

Svante

I use two volvo truck intercoolers thats welded together. I can take some measures for you if you like, but i think a 3 or 4" aftermarket that fits will do just fine. I had to remove my AC radiator to make room for mine.

/Svante

Impala Balko

I am hoping to retain the AC this why I decided on going with a remote mount turbo setup

Svante

I understand! I guess there should still be plenty of IC's that would fit. How much boost are you planning to run? Turbo?

There's a guy in town that runs an old e36 M3 BMW, he has a rear mount, non intercooled setup. Makes 1280hp! He has a intake temp of 243 deg F. But he runs E85

Svante

Ok some updates on the Turbo swap!
I finally got my 2-post lift so the project could move forward. I replaced the T4 flange on the exhaust with the T6 divided.

The tubo fits, but it´s a close one ... Talk about a huge unit. Anyway the AEM 5" in 7" long oval filter is preinstalled just to check the clearance for now. The oil tank i made for the Holset fits the BW perfectly, so i did´nt need to make a new one!

I need to make an adapter flange in the lathe to have the rear silencer in place, but maybe i can take it for a test drive in the end of this week.

/Svante.

ANTI VENOM

Very nice work. I look forward to your next update when you get a chance to "test" it. Have fun.

Svante

Ok.. Today we got the first testdrive with the new turbo. The first impression is that it was a bit slower on the spool than the holset, but after driving some more we realized it was basicly the same lag as before. The boost is 14psi for now and it spins the rear tires on all gears. I will try to drive it when it´s warmer in the air and maybe i get some more traction.

The goal is to pump up the boost to 25psi and if it does´nt detonate or show some other issues i will leave it there.

Here´s a short clip from the phone
/Svante.

Fotograf2

Hej Svante
Var köpte du turbon, jag antar att talar svenska
Where did you buy the turbo