RPM limit

[rabbitman]

You have a 1.9 head?

All the better, lower Compression Ratio's are better for boosting. If a 1.6 can handle 30+ already having 23.5:1. The 1.9 combo will be 17.5:1 (??) and will be much happier with that much boost.

The magician as in Giles? He can do anything

The 1.6 is 23:1, the 1.5 is 23.5:1......

Yeah Kevin, IIRC the AAZ head flows better and lowers the CR, exactly what you want when adding boost.

See, "boost" isn't what makes more power, it's pushing more oxygen into the engine that gives more power. So a lower CR lets you fit more air in the cylinders with the same boost, raising the CR like you're talking about totally defeats the purpose of the AAZ head. A lower CR will give you the same power with less boost pressure more reliably.........

Someone correct me if I'm wrong

[NintendoKD]

No, you are right, using boost on my setup is practically ideal.  The turbo literally increases volumetric efficiency, that I do understand.  I really want to avoid having ridiculous cold start issues, as this is an IDI setup.  I wonder if my block heater mod will really help much, well, only one way to find out   Yes I do have an aaz head, got a complete head from another member here for a sweet ass deal, it is currently on it's way.  I plan to do a port and polish, and I am still looking for intake and exhaust/turbo options for this setup.  I like the VNT/VGT setup to give more power throughout the band and no lag. I am doing this build for the simple fact that everyone says that I can't have my cake and eat it too   I often second guess myself, and have the type of personality where I like to kick my tires before I drive off...... TWICE!  Truth be told I just don't want to crash and burn while doing this very unique build.

Thanks guys,

Kevin

[Rabbit on Roids]

im gonna keep saying this...

you are overthinking the build. most people keep their engines bottom ends stock, or very close to it. thats why they get reliability. im still using a VW oem 1.5 short block. boosting to almost 30 psi with a fiber gasket. the head is still going to be the week point. you are overbuilding the hell out of the bottom end in my oppinion. why dont you spend all that money figuring out how to hold the head down tighter so you can run 40, or maybe 50 pounds of boost. ive heard theres a guy that has a cast iron headed 1.6 with 80 psi boost... just some food for thought.

this is not a gasser, we dont need to mess with so much stuff to make the power.

[rabbitman]

I don't think I'd worry about cold starts, you live in california? If I ever do a real build I'd start with a hydro block, add an AAZ head and hope it started good enough . Block heaters help a LOT.

[NintendoKD]

I understand where you are coming from there rabbitonroids "and yes, I know your name, but I prefer to use your screenname due to privacy" I don't plan to drive this thing like i just stole it ............. everyday   I would rather have the bottom end built, such as the coated pistons and ARP fasteners for increased reliability.  I applaud you for using the 1.5 in that way, it's great, and you truly have my undying respect.  I like to push things to the limit to some extent and this is no exception, I would love to have a cast head and run that much boost, but then I would lose out on the low end.  There is a delicate balance here, and I know it is difficult to define for everyone here, but it's my build and I would like some advice to that extent, not throwing any anger around here, just saying why I posted. I would love to have had an hydraulic block, but fate had other thoughts

[8v-of-fury]

Keep on building it the way your building it, treat it right and it will live on to see the engine bays of many VW to come.

Think.. vw designed a diesel engine that with care could reach a 800-900,000 miles. This will be built two, three times as strong? Such a robust engine will be around for yearrrrrs to come! DOO ITT

[NintendoKD]

Thinking about starting a thread on piston coating services, anyone know about it?  Would like a good reputable service to do mine that will provide long lasting, durable results.  Not for too cheap "I don't need cheap results" but affordable.

thanks guys,

Kevin

[truckinwagen]

swaintech

[NintendoKD]

I have heard that somewhere else..... here, I think   Thanks, and keep em coming.  I'll prolly give them a call tomorrow.

[VWSmokr]

Topic seems to have shifted to coatings...

AFAIK Tech Line Coatings (home office & manufacturing still in Texas?) is the actual manufacturing source of the coating materials that most shops use.  http://www.techlinecoatings.com/hi-performance/  NintendoKD, they have a shop in Murrieta, not all that far from you:
Tech Line Coatings, Inc.
26844 Adams Avenue, Murrieta, CA. 92562   (just south of 215/15 freeways' junction)
Sales : 1.972.775.6130
Fax   : 1.972.775.8125

Tech Line has coatings to keep heat out, hold heat in, reduce friction, conduct heat away, plus other stuff.  They can coat the piston tops (about 0.015", as I understand), combustion chambers (or surfaces, as in our diesels!), valve faces, entire exhaust ports, exhaust manifold interior/exterior, turbine housing inlet, and obviously... an entire post-turbo exhaust system. (That's what I'm counting on; currently saving coins to have some of their handiwork done to a couple of my turbo engine builds!)

Back to your discussion of compression ratios: seems like adding 0.015" to the piston face and a like amount to the combustion surface will require slight milling of piston tops to avoid impact or raising the C.R. too high. But the advantages in superior heat rejection and better fuel burn should be worth it IMO, even for non-racing apps. I'm thinking efficiency & longevity here, more than maximum raw power. Anyone have experience on this?


J.R.
SoCal