Engine Rebuild Qustion From Oz

[TurboVS]

Hey, I have no idea if this is the right place to post this, but I am from Australia and own a VS Commodore with an Ecotec V6 3.8 engine. These engines are not turbo out of the factory but I have put a ball bearing turbo on it and now I want to rebuild the motor to handle 500HP+. Before I go any further I'd just like to know if you guys know if my engine is the same as your 3.8. Cheers

Here is a link to my car it is way out dated, I now have a Tremec 6 speed and more boost but you'll get the idea.

http://www.fullboost.com.au/cars/readerscars/2002/vs_damen.html

 

[Kevin Turch]

Wow, thats nice..!!!!

 

[mcad_c]

Nice car.

Some questions...

Do you know the bore and stroke?

Also the cumbustion height of the pistons will be a tell tail sign.

The 3800 Series II went into vehicles in 97.

Hope this helps

 

[mcad_c]

This may also help...

3800 Series II

 

[TurboVS]

Have a look at this link and under the ECOTEC V6 section should tell you all you need. We used to have an almost identical engine in the older model cars to you guys but from my model onwards the block and everything else was changed, but still it is of the same family. Anyhow ahve a look at the specs of the motor and see what you reckon.
Cheers

 

[mcad_c]

What link?

 

[TurboVS]

Oops sorry.

http://www.holden.com.au/www-holden/action/techdata?modelid=4000

 

[mcad_c]

Well it looks like the same block, only b/c they share the same info for everything but compression ratio, tranny, and fuel.

I can't answer specific details without more detailed dimensions.

Sorry

I'd like to see more on the OHV head.

 

[nocutt]

Originally posted by TurboVS
Have a look at this link and under the ECOTEC V6 section should tell you all you need. We used to have an almost identical engine in the older model cars to you guys but from my model onwards the block and everything else was changed, but still it is of the same family. Anyhow ahve a look at the specs of the motor and see what you reckon.
Cheers

Not bad at all...I am not familiar with the PCM reprogramming? Are they strictly down under?
Anywayz to push 500hp with that setup efficiently will entail several mods and more cubic $$$...I don't know the specs to that turbo but it will be safe to say the compression to the engine will definately have to drop to about 8.5 or even 8.0. Problem is your drivabilty will suffer (off-boost-throttle response)...in my opinion using 9.5:1 (or 9.4:1 CR) and getting the right AFR complimented with the right igntn curve you can get very well pass 400 hp...

 

[TurboVS]

The turbo is a GT25 450HP, but I am considering going to a GT30 600HP. At the moment we have around 400HP on 10psi boost with the CR at around 9.5:1. We are considering dropping it down to 8:1 or even 7.5:1 as we want to run 20PSI.

 

[nocutt]

Originally posted by TurboVS
The turbo is a GT25 450HP, but I am considering going to a GT30 600HP. At the moment we have around 400HP on 10psi boost with the CR at around 9.5:1. We are considering dropping it down to 8:1 or even 7.5:1 as we want to run 20PSI.

Moly ...ish on a stick
LOL! I hope this isn't a daily driver? In my own opinion if you are going to open the car up then I wouldn't go past 8.5:1 that is just me though...lower than that is very UNCOOL! If I had to do mine again I will have opted for a 9:1CR. Back when I turbocharged my 3800 there was basically nothing out there...Now that is a whole different story. I think the most important thing is AFR and your Igntn map during boost, since PCM reprogramming is not a problem, going lower than 8.0:1 will be unecessary especially if the vehicle is daily driven.
GT25,GT30 this are BB turbos ? they sound familiar are they the new Garrett BB series?

 

[TurboVS]

No it isn't a daily driver so it doesn't really matter. And yeah those are the new Garrett Ball Bearing Turbo's. What sort of CR will I need to run 20PSI???

 

[nocutt]

Originally posted by TurboVS
No it isn't a daily driver so it doesn't really matter. And yeah those are the new Garrett Ball Bearing Turbo's. What sort of CR will I need to run 20PSI???

It is relative my man...You can use a 9.5 CR to run 20psi but the problem it your tunning window shrinks vastly...this is assuming we aren't talking on stock heads and rods...lol! On the other hand, 8.0 CR sounds good, but you will have to either push more boost, get a bigger turbo (which I know you already said) or push more RPMs outta the motor to hit 600HP...it is a point of diminishing returns...you just have to make the engine more efficient 600HP is a lot to get what are you plans?

 

[TurboVS]

My plans are to get 500HP. Do your 3.8L motors have cross bolted mains? Apparently our ecotec V6 is an upgraded version of the buick and uses tougher rods and crank as well as 4 bolt mains. I am not entirely sure what your 3.8 is like so I can't really compare. I have seen 13psi in mine stock bottom end and it seemed fine, what sort of boost do you blokes normally run over there and what HP can you get?? You guys know more then us that's why I am asking all the questions as no-one does this sort of stuff over here.

 

[mcad_c]

The 3800 series II has cross bolted mains.

I've seen as high as 13.9 LBS of boost. I dynoed 245HP & 346TQ with ported exhaust manifolds & stack muffler. That was uncorrected at ~2500ft elevation, 29.x baro, 75 degrees

I have not been back to the dyno since the ported SC, headers, and 3"-2.5" exhaust has been added.

Mods

2.8 pulley
Stock SC & TB
P&P Intake, heads, exhaust manif.
HL cam
IC
3" DP, Stock cat, no ubend, no res.

 

[nocutt]

Well you can do a very conservative comparison between the three engines although I will like to say two engines...the L36 and L67 use the same block but different bottom ends. OK the heads are slightly different but that is due to injector placement. My point? While an L67 can push more boost it is also not as efficient as an L36 with FI. According to the info I have you can push a stock bottom end on an L36 farther than 2bar, but like I said the tunning window avilable will diminish...you will run into KR, one will have to use "ye good ol' gas"...on the other hand I know the L67 bottom end can push up to 20psi religiously, but not with the stock blower...

To be really conservative, this is what I plan on doing...hopefully (college student)...but to get a cam to bump the powerband, use a bigger turbo (I am currently rebuilding a '87 GN t3/t4 to ta49 specs) get a reprogram (mainly to get higher shift points 6500RPMs and the God forsaken 108mph speed limiter)...run 14psi with a mildly ported head...this should put me about 500hp...I have know idea what to do to the tranny at this point, which seems to be my one and only brick wall...No sponsoring is hard on the wallet...lol! To run 500hp you will need to flow (well the turbo) at least 45lbs-50lbs of air/min...that is the 'catch 20'...