PDX-944

Cross posting from the watercooled area... didn't see this section!

https://rennlist.com/forums/924-931-...l#post14487069

lots of things im still trying to work out with my build!

Humboldtgrin

What block are you using?

PDX-944

ha I went to Humboldt state for 2 years. my racing began with rscc autocross!

I plan to use my 2.5 block. probably partially fill it

Paulyy

wait wait wait. You're going to put a BorgWarner 6258 on a 3.xL block?????

440hp turbo? Same size as a gt2871r? or a gtx2860r

It is a 1.8-2L turbo!

PDX-944

I have been running the 6258 for the last 2 years on the 2.5, and its great! quick spool and plenty of power!

Thom

6258 should be ok if he doesn't rev it beyond 4000 rpm. It's all the V8s' fault.

PDX-944

not sure where that idea comes from, but I have been running it competitively for several years now, and its been great. im not looking for a dyno queen, im looking to supplement the low end.
after the conversion, it may be too small. I still have the 6262 laying around as well, but id have to do some reverse engineering to get it back on. so, ill use what I have for now and evaluate after. first step is getting the motor built and running.

Thom

Sure. My comment was a bit tongue-in-cheek.
The first turbo on my 3L 8V was also too small though I first thought it would be just fine. Enjoy the build!

PDX-944

and it may very well be. but that's a cost for a later time!

the v8s are the worst.

Humboldtgrin

I would look into a 3.0 block. You'll want windage ports with that displacement. And use a 2.7L 8v head for better breathing. Or just go with a 16V head. And open another bank account. I have yet to see a "budget built Porsche turbo engine". And if your increasing the displacement and spending the $$$$ on wet sleeving you may want to rethink your final goal. In the end it usually costs a lot more then intended.

Paulyy

Check out Jet951, he has a budget built 3L and he tracks it and uses it on motokhanas on top of that he drives it to work!

rlm328

He will be OK with the 2.5L base block windage ports are no big deal and most decent machine shops can bore them out for a reasonable cost. The problem with the 3.0L base block is the water return on the 8v head does not match the 3.0L block so one of them has to be altered.

I also have an "under-sized" turbo according to a lot of the experts on this site. Mine is sized for mid range power where it starts spooling at 2500 rpm,, reaches peak by 3000 rpm and starts running out of legs around 6000 rpm. I will put up against 90% of the people on a track around here and run away from them. It all depends on what you want to do with your car. Put it on a dyno see what it does and if you want to change it you will have some numbers that you can base your change on. Most of these turbo companies are loaded with geeks who will talk to you all day long about what you need. You do not need to worry about low end torque with the 3.0L as it pulls like a V-8.

There are a lot of lessons learned in regards to the Darton MID sleeves, you may want to take some time to review.

I do not like the offset grind although a lot of people seem to like it.

I would use a 3.0L crank with Pauter rods, pistons are up to you, I am running JE that are for a 3.1L motor. I would not go much bigger though I know of one 3.3L but I do not know if he has it running yet. One of the reasons you do not want to go much bigger is heat. I run 14 psi boost for go fast weekends and 17 psi when I get serious, I do not run 17 psi unless it is cold outside (below 70 F preferably colder)

You can get a Cometic head gasket made to just about any thickness you want, so your piston clearance shouldn't be a problem, these alusil blocks also grow like 1/4" more than the steel components so you will gain a little in that arena also as the engine comes to operating temp

You will want to get the Bosch 044 fuel pump as the stock fuel pump cannot keep up

PDX-944

So I have found a 3.0 crank for 800 plus shipping.
Offset grind and balance through Moldex is $650.

OR

They can make me a whole new billet crank with correct offset for $2500-2750.

I don't think its worth double the cost to me, so ill probably go with the offset grind...

rlm328

Why do you need a billet crank? Standard 3.0L crank drops right into a 2.5L block. You need to get a different set of rods. Pauter Rods are about $1,000. Difference between your offset grind and new rods is 350, and you are using standard Porsche parts such as bearings.

PDX-944

with the 3.0 crank im still sending it to be offset ground to 94mm.
so I either buy a 3.0 crank, and pay to offset grind, or pay more and just have one made to that grind.
I will be using either mitsu or small block rods, smaller rod bearings, etc.
no Porsche parts inside left! okay some. but not much!