sinatra vette

what is the connection between the cadillac northstar and the zr1 engine? i heard somewhere that the northstar has something in common with the zr1. anyone know if its true?

phrogs

well the basis of the northstar was copied from the LT5 these are completely different engines but I think that the GM guys renginered the motor after tearing into a LT5.

Aurora40

They definitely have similar basic features. The both have the ladder style crank mains, the layout of the chains is similar. They are both aluminum castings with steel liners, though the Northstar's liners are cast in place and are not removable. The N* didn't have nikasil coatings, didn't have the dual-cam profiles, etc.

However the N* had some better features like a much better digital ignition system, I believe with a 23-slot crank reluctor. And the N* introduced the composite intake manifold.

There's definitely some family heritage there.

sinatra vette

?! the zr1 has nikasil in it? i have horror stories of this. my 98 jaguar xj8 had nikasil in the engine bores. ive heard bad gas eats at the nikasil ,and total compression loss occurs. i hope the zr1 s are not like that! thanks for the info though very interesting stuff

phrogs

Yeah the liners are nikasil but I have never heard of any problems like that with these, Ferraris use nikasil as well never heard anything about bad gas either. but not that it can't I have never heard anything.

Johnny

Rkreigh

the LT5 has liners coated with nikasil and it's incredibly tough stuff. the liners will last well beyond 200k and the rings wear out long before the liners. not sure about the jags but never heard anything about problems with the nikasil.

lite blue

Nikasil

Rkreigh

thanks for the link. so it's the sulphur in the low quality gas that is the kryptonite to the nikasil.

moral of the story, don't save a few pennines on gas, use the good stuff!!

dallas916

That's the deal, so they say. Since I have one of each (XK8 and ZR-1) I never go beyond the Chevron for my gas. I didn't know my old 930 had nikasil liners but needless to say it got the good gas back then (circa 1980's). I've never had any problems with any of mine, but apparently a bunch of the Jag 4.0 V8 engines with the liners didn't hold up. I think a study of where these failing cars were located and the fuel/oil they used might tell the story more accurately. Of course, having Jaguar tell their new owners that they could go 10,000 miles or once a year between oil changes probably didn't help. Doh!

Rkreigh

fyi

marc haibeck did a great article comparing the lt5 and the northstar.

the "MY 95" LT5 engine with the redesigned heads, intake and single injector per cyl used the northstar computer so GM didn't have to redo the old LT5 ecm. it would have made 475+ way back in the day and much more if modded. the intake and cyl heads were really nice. shame it never got beyond the prototype stage. the variable lift cams were pretty trick and adopted by porsche

graham did a very nice presentation on that engine and hopefully someday we'll see it running. he has some raw castings but it will take a ton of work to complete it.

sinatra vette

Aurora40

My bad about the steel liners, the Z's are aluminum which is why they have the coating. N* has a cast-in-place steel liner.

Except it would look hideous, I wonder how an LT5 would perform with a composite intake manifold.

ZRWON

YES, The LT5 led the way for research and many technological developments including design, materials, production and engine controls, thus slashing development time for the Northstar, Aurora by several years. I also heard from some source that even the quad 4 benefited from the LT5 effort.

rhipsher

Just google (Cadillac north star engine) and wikipedia tells all about it. http://en.wikipedia.org/wiki/GM_Premium_V_engine

dallas916

[QUOTE

Except it would look hideous, I wonder how an LT5 would perform with a composite intake manifold.[/QUOTE]

Hmmmmm....then how would we P&P them??

tomtom72

I have always wondered if one of the reasons that the big brass at GM gave Dave Mac permission to do our LT5's was to provide some heads up R&D for those other motors.

Rkreigh

I'd like to do a "moon BB style" carbon fiber cross ram with slide throttle bodies. it would look awesome and flow a ton.

but I don't think the intake is much of "choke point" on the engine.

cyl heads are. if the intake flows more than the head port, engine is restricted at that bottle neck.

even the best flowing cyl heads are just over 300-330 cfm which is "entry level" for decent LSX heads which start at 330 and go up closer to 400 cfm for the big doggies (ported LS7, L92)

there is a company here in Newington VA doing a port job on some LT5 heads, I'm anxious to see what they come up with and how much power they make. they are going on a midwest stroker, not sure who though.