Engine Build 3.2 -> 3.4 - What do you think?
 

So as I've gone down the road on this engine build, I got a little "while I'm in there" syndrome and made a few changes. Here's how it's shaken out so far...

Pistons: 98mm Mahle 9.8 compression, Max Moritz style
Cylinders: 95mm KS, to be sent out to EBS for bore out to 98mm
Cam: Web 20/21
Rod bolts: ARP M9
Crank: 930 Std/Std (When we opened it up, that's what was in there)
Case: 930 (When we opened it up, that's what was in there - identical to Carrera case though)
Head Studs: New steel
Heat Exchangers: Stock Carrera
Muffler: Stock Carrera
Intake: Stock Carrera

Am I missing anything here? Any suggestions? The intention is to do a Steve Wong chip after the hardware is sorted out. Any guesses about how much power this setup will put out? I'd like to do a less restrictive muffler setup, but I haven't been around other folks cars enough to know what I like and what I want. Motor is intended as a fun street setup, maybe some DEs.

The new (used) Mahle pistons:
http://forums.pelicanparts.com/uploa...1442433427.jpg

Hmmm... With a sport muffler, you could be in the 260-270 range. SW once suggested that even the most vanilla 3.4 setup can get there. It is debated, but an open cup style sirbox and fresh air filter may add a few hp post tuning. I enlarged my throttle body to 66mm also. Prob overkill, but while you are in there...

I agree with snake dude with that kinda work , if you let it breath a bit more even headers with sport muffler and a properly tuned sw chip.. You are talking maybe 20 more low end seat of pants hp/torque woohoo would be a shame to leave that on the table. Can be done with little added noise also just my 2 cents

Do you have an original 3.0 engine in there or is a a 3.2 retrofit?

Stock Carrera should mean Motronic.

Probably too late now, but have you looked at the rothsport 9.8 compression 95mm pistons built for stock Mahle nikasil cylinders? That's the super hot 3.2 set up now and will save you some serious $$$.....more than enough to get a GT3 oil pump in there which is a must for sharp end track use

Won't get you 270bhp, but you'll have that at the crank using 91 octane.

Yeah, a low restriction exhaust is the plan. I just need to listen to more cars in person to figure out what I like. I'd prefer a system on the quieter side. Any suggestions?

Yes, the engine is a 3.2 retrofit with Motronic.

I like it.

I'm building essentially the same but a 3.2 from a 3.0 CIS with the MM 98mm wedge Mahle pistons.

If you haven't yet purchased your Webcams, consider Dougherty cams DC19 profile. It's the same profile as the WC 20/21, but he'll grind them on your stock cams. This will save you some dough.

Also, due the aggressive ramp of these cams (DC19 or 20/21), aftermarket springs are recommended. I'll be using the Eibach 20444.212 http://www.summitracing.com/parts/eib-20444-212/overview/

Thanks Josh. Already have the cams, got them for a pretty good price. Do not have springs... did not know they were required/recommended.

So I did some quick googling, not coming up with any info on this. Can you point me in the right direction?

Josh, if you did not bought your springs yet, or tmaull, if you are planing on buying these springs. I have a brand new, in box Eibach 20444.212 set, that I purchase from Summit when they were cheaper and did not installed them.

I can sell them for $100. Just trying to get back what I paid for plus freight cost.

(Sorry if this goes against the forum rules, and I'm not using the classified section. I did not intend to sell these springs, and to keep them for a future project... but if it could help some fellow Pelicaners...)

The Rothsport site says they're NLA?

Buy Hugo's Eibach springs and pick up some Aasco Ti retainers from EBS. That's probabyly the best deal out there.
I'd go bigger with the cam, since you should have plenty of clearance with those pistons.
Supertec has some oil pump mod for the 3.2 pump that sounds like a good idea, if you're not going wild with the revs and don't want to go all out with a GT3 pump.

So I already have a the cam, and I think it's a good solution for me. After all, this is a street car. Hugo, sent you a PM.

As an example, AASE Motors built a similar motor last year, Mahle 98s, single plug, 964 cams, modified cone filter setup, and the full stock exhaust and muffler, nothing else. If the motor is built right, it should dyno at least 230 rear wheel hp SAE on a Dynojet. This motor dyno'd 236 at the rear wheels after a remap, or about 270-275 at the flywheel (blue curves below). Red curves were with the stock chip.

http://forums.pelicanparts.com/uploa...1442515291.jpg

AASE has just finished a revision of the motor in a slightly different configuration with 10.5:1 custom pistons, twin plug, DC 993SS cams, and will be retuned again shortly.

I helped on a motor very much like what you are doing with great results:
http://forums.pelicanparts.com/porsche-911-technical-forum/851912-my-87-3-4-maf-project.html
see post 63 for final dyno numbers.

I agree with SW that hitting better than 230 WHP should be no issue if done correctly.

Here's my thoughts based on few builds I helped on that had excellent results and perfect street driveability.

Consider 964 cams or DC 21 Cams also.

SSIs work very well on this setup, I know some will disagree but a 3.4 motor I did early this year showed otherwise. Or use B & B Headers and dual out mufflers 1.75 inch primaries. My personal engine is a 3.2L Euro and dynos in the 228-232 WHP depending on season and temps I also have SSIs with no issues at this power level my engine also has those Web 20/21 cams.

Bore the Throttle Body and possibly consider MAF.

I believe they are controlling distribution. I think they want the customer to send them their cylinders so the pistons can be properly fit. Rothsport markets it as a package deal and is surprisingly (comparably) inexpensive.

This is the 3.2 spec for the PRC Spec 911 class. About the same output as the POC Spec Carrera class motors (235bhp/205tq), but they get it running pump gas.

SSIs are too restrictive on a 3.4. I have dyno'd tuned many 3.4 and 3.5 motors over the years that had them, even engines built with every trick in the book by the best of air cooled engine builders, and the motor struggles and chokes off by at least 10 hp over the factory stock exhaust and muffler. Same motor going back to the stock heat exchangers and muffler, and either a premuffler or sport cat, and an instant 10+ hp and a broadband increase in torque.

Also, extensive tests I have done, along by others have shown no HP increase with a MAF on the 3.2s and 964s, which have the same air flow sensor. None, not even one hp at 7000 rpm at full throttle. Tests I've done were in the scientific method going back and forth within minutes on the dyno, equalizing air fuel ratios and ignition timing to identical values, using the trickest MAF setups one can imagine. The restriction of the intake is not the air flow meter, but the airbox and snorkel attached right before it. We have also done extensive tests on air filter setups, and we use a modified and ported version of the cone air filter setup from MSDS which eliminates this problem creating a large bell mouth velocity stack into the air flow meter, which is superior to standard standard straight tube MAF sensor setups with a standard cone filter on the end. Anyone that dyno's a difference between an aftermarket MAF vs the stock AFM setup is really just comparing the difference with and without the stock airbox setup.

Thanks Steve. 230rwhp sounds great to me - about what my STi did. So I'm trying to make a decision on springs/retainers. My springs meet spec and my engine builder thinks I should stick with what I have. Higher compression springs means greater cam wear, etc. How much of a difference is it? What will be the difference in performance/reliability if I stick with what I have?

Did I miss where you mentioned twin plug? It's a benefit at 3.4. This is nearly the exact motor my daughter is building. Same cams, pistons, etc. we have 1-3/4" headers into a sporty muffler that she is making into a GT3 like outlet. She's running twin plug with the Andial splitter.