Anyone here promoting or running the 19:1 CR philosophy?

[Pillow]

I am new here but have been lurking and reading A LOT!  You guys have loads of great info and advice here...  Now if I can keep up with the acronyms I might absorb more.  LOL

Some people are rocking some really decent PSI and most are playing it safe with 12-15PSI.

Now my experience is mostly with the Detroit designed GM 6.5TD motors, but many of those guys drop the CR to 19:1 and raise the boost PSI considerably with good results.  FWIW a normal 6.5 when properly modded runs in the 13-15PSI range as well for a IDI engine. 

My question is any Dubbers dropping the CR to crank some serious boost?  If so what are the results?

Thanks! 

[Garrett]

I would think with the lowered compression cold starts would be hateful... But I'm not too sure what has been done around here!

Welcome to the forums!

[BellCityDubber]

IIRC malone was running a 1.9TD head on a 1.6TD block which dropped the compression to something like..... 17:1???
but it DID drop compression.... and it has been done...

[burnt_servo]

how much boost are you wanting to run ?

[Pillow]

I was thinking 25-30 PSI. 

Granted I am not sure if ARP studs and a metal HG can contain that..?

The only way to get serious HP out of these motors of course is more fuel and air.  The air is easy given the right Turbo...  But can the engine handle it? Dunno.  Next area of research will be getting the fueling requirements taken care of.  4BT IP?

Thanks,

[theman53]

Smoking eddy is running that kind of boost with a 1.9 head on a 1.6 bottom and everything else but exhaust and wastegate blocked stock I believe. You could run that much just by blocking the wastegate on a KKK K24 stock turbo or the Garrett T-3 that came stock on the 1.6. I think Zukgod was running 37 on his 1.6, so your boost #s are or should be easily attainable. I hope I could boost that much with my project, but until it is intercooled I don't see running anymore than 20 or so. As for fuel the stock pump does well, but before going to the 4B you might be cheaper and better to go to the vendors section and look for Giles performance diesel injection. He can do anything that should be done to a pump and more. Also I believe Sourkraut figured out that if you put a 1.9L head on the 1.6 block it takes the compression down around 19.5:1 or so. The main difference though is the port work in the 1.9 that is why it is more desirable I believe.

[RabbitJockey]

yeah 1.9 head drops it to around 19:1 or a bit more, i forget,  malone had a few other things that dropped his compression a bit more.  from what i understand 14-16:1 would be best, but good luck starting it haha.  if you're gonna run more boost just be smart and run an intercooler and watch exhaust temps,  i skipped both those and cracked a head, but i was young and just doing what ever, i am so much wiser now haha

[kibs45]

I know dropping CR is the best way to crank up the boost, because diesel needs cylinder pressure regardless of how you build it.  What I am not sure on is the proper use of CR on a IDI versus a TDI.  I know direct injection Cummins go as far down as 13:1, (as a side note, the higher the HP the lower the CR generally).  I would be incredibly interested in someones expertise in the IDI world...  I think this gets into the area of "quench"?  IE the size of the combustion chamber versus the space between the piston and head at TDC, someone correct me if i'm wrong...

[burnt_servo]

I was thinking 25-30 PSI.  

Granted I am not sure if ARP studs and a metal HG can contain that..?

The only way to get serious HP out of these motors of course is more fuel and air.  The air is easy given the right Turbo...  But can the engine handle it? Dunno.  Next area of research will be getting the fueling requirements taken care of.  4BT IP?

Thanks,

if your only looking for 30 psi , no worries  my  brother has been running 40 - 45 psi boost in his samuria  for the last year till he snapped the shaft  on his turbo  , then i turned his pump down so he is now only seeing 35 psi max boost .

he's running arp studs and a 3 hole 1.9td  metal head gasket  , on a 1.6 , with a 1.6 head and oversize pistons that would require only a 2 hole  head gasket .

before i  recently swaped out heads on my car ( due to very bad cracks due to overheating when my rad hose blew )
i was running around 25 psi with a stock 1.6 head gasket , and stock head bolts retorqued 1/4 turn .

i now have arp headtsuds and a 3 hole metal headgasket with a freshly rebuilt and heavily ported head ( i'm curious to see is the porting has any effect on boost / power levels with nothing else changed .

[klang]

I'm going to run 20:1 on my M21D24 with around 50 PSI =)

Will it hold? Probably since theres is guys out there who has this setup..

// Klang

[Rabbit on Roids]

50 psi eh?
how you gonna hold that head down?
how ya gonna keep the gasket from shooting out the side of the head?
i talked to some people on here, about my 2.0 audi (same engine as yours, minus one cylinder)
and they told me it could run 40 pretty reliably. but not with a stock head gasket or bolts.

[MJF]

Why do you want to use so huge boost??? 30psi is good for 230hp in 1,6 with 1,6 head. Real question is: How much power do you want? Then choose correct parts for setup. Blocking wastegate is still no way to make power. Under 200hp, there is no reason to drop compression from stock.

[rallydiesel]

Yes, you'd be better off in the long run to port the exhaust and run a boost controller. That way you'd end up with lower boost but more power and greater longevity.

[Pillow]

Excellent info guys!

So it sounds like a 1.6 engine with 1.9 head and Metal head gasket with ARP studs could handle 40PSI nicely with the 19ish:1..?

Time to run some more compressor maps and numbers! 

So with that kind of setup what will fail first?  IP cannot pump enough fuel?  Rods exploding?...

Thanks!   

[8v-of-fury]

So if I were to make a frankenmotor.. Living in Canada what Could i do for winter starts? Good starter, wires, Gp's and battery?

will it suffice when i need it to start on a -15c day? I mean like i hear of some people having troubles with just a normal 1.6... What do you guys think? I would have to plug it in?