zoso_turbo

Hello all....

Well, I am brand new to this Rennlist forum and new to Porsche forums in general, although I have owned my 951 for almost 10 years. As I sit here and compose this message, I am watching the infamous Gumball Rally and recovering from being diagnosed with Viral Bronchitis.

So...I am in the midst of completing Phase III of my 951's rebujild. I completed the exterior and interior a few years ago and am now completing an engine rebuild. The engine is being rebuilt by a local performnace Porsche shop and has been completely removed and completely disassembled. My current plan has the following components included:

* New Pauter Rods/bearings
* Cross drilled crank, balanced and knife edged
* Head job
* Chips (vendor unknown at this point
* Flywheel lightened
* Sport clutch
* LR 3" exhaust w/magnaflow and pass thru pipe
My goal is a solid car that will be used on the track 20% and has a rwp of 300+

Here are my questions....
1. I would like to upgrade the turbo...I am thinking LR Super 61, your thoughts on this turbo? Or others?
2. What chip set should I use? My mechanic likes Authauthority
3. The pistons are not being treated or replaced, should I consider something with the pistons out of the vehicle?
4. Should I upgrade injecctors? fuel rail? Currently not in the plan.

Anyway,,,,,ZI appreciate any and all feedback and look forward to interacting more on this forum.

thx...

=dan=

zoso_turbo

Ski

The 61 turbo is a nice turbo and will get you to your goal. Chips, well depends on what you want to do with AFM or MAF and piggyback. Be advised here: go with one vendor if you choose MAF/chip/piggyback combo. Do not forget fuel injectors and fuel regulator, all this ties into everything else. Lindsey or Vitesse chips and decide on the $$ you want to spend. Forget Autothority.

Piston coating - you and your shops decision as you might need to check the tolerance on piston/cylinder clearance if you coat them, which means you may need to get the bores redone to meet tolerance. Head studs?

pic of Swain coatings with gold coat



pic of LR coat with top thermal

zoso_turbo

ski....

Those pistons and block look outsanding. Exactly what was done to the block? My shop has told me that the block looks ok and that even if there were scores in the cyliinder walls, you cannot touch an alum block, it would need replaced.

What size injectors should I use? and what about a fuel regulator in addition to the fuel rail. In this scenario, I dont know what I dont know and am concerned about not completing the job correctly.

Thx again for the post.

=dan=

Ski

Well if they told you it would have to be replaced and the bores couldn't be repaired, you might want to get it out of there and to a different shop.

The block was just bored over to first oversize, 100.5mm, and finished with the recommended procedure with the Sunnen machine, stones/felts/silica paste. We've had 4 engines done at Duffin Engine in San Antonio TX. The gold pistons are Tom C pistons(Arias) and the second group are Mahle 100.5.

If you choose to go with LR, probably 48 or 55# injectors. Vitesse, stage II kit, usually 55# injectors - just depends on your budget.

I'm doing this engine now for a friend, block will just be polished and refinished bores with new rings, link here:
http://951forums.com/forums/index.ph...topic=419&st=0

pk951

For injectors depends on HP you will be making 55 good for 300 to 330 Hp to wheels.

If you plan to go to the track you might want to keep injector-duty cycle 60%, so you will need bigger than 55 injectors.

zoso_turbo

What are the consequences if I do not upgrade injectors or the regulator initially? I do want to drive the car in upcoming DE events, am I putting the car at too much of a risk by not upgrading until later.

Also, how necessary is it to upgrade the MAF? At this point I am thinking about staying with the stock unit.

thx for the feedback.

=dan=

docwyte

Injector duty cycle to 80% is fine at the track, that still leaves plenty of headroom.

A MAF will make a huge difference in drivability and will also get you alot closer to your HP goals.

Ski

How much money do you have left for upgrades after the shops bill? Stock rods are good and knife edged crank - that money could have been spent better elsewhere at this stage of your build, just my .02 If you have not purchased the rods and sent the crank off to be done - maybe think again about your turbo and other items. Our track car has stock crank, stock rods, Tom C piston, o-ringed head with a bit of port work, III MAF, Mafterburner, 55# inj, AFPR, Kokeln V(similar to 61) turbo, 17psi and puts out 351/347 to the wheels.

zoso_turbo

ski...

Rods are in and crank is on its way back from LR. My thoughts here were to get these upgrades done and not worry about them in the future. The ole "since I am in there syndrome".

If I hold off on the turbo today, I am concerend about wanting to upgrade in the near future and having to pay for removal, etc. So,,,If I can upgrade the turbo now, as well as the other parts mentioned (rods, crank), I will mostl likely wait on the MAF, fuel pressure regulator and injectors for one season.

What are your thoughts on the Kokeln V turbo vs the LR Super 61?? I am trying to avoid too much turbo lag, hence the reason not to consider a larger turbo.

Or, do I wait until I can pull the trigger on the turbo, injectors, fp regulator, etc at the same time,

thx for your perspective...

Ski

Well if that's the case, I would call LR and for sure get a WBO2 to watch the tune of the car.

pk951

To bad you bought the 3-in exhaust, take a look at there 340-kit has everything you need http://www.lindseyracing.com/Merchan...ode=944PACK340

MR951

You can still get that kit from LR w/out the exhaust system. They'll work with you to give you a deal on the package.

Ski

yeah, what the hell, pull out the VISA and go for it all at the same time - think of the labor you'll save!