I'm N/A and I need guidance...

Ok, quick run down... I built an n/a b18c1 with the intention of running nitrous in the future. The tolerances were done with this in mind. The car is doing great on motor, no spray... it pulls like a beast and I am satisfied, but I am thinking about not spraying it and going boost... only problem ? My compression is 11.6:1 and I have domed JE pistons.

Now with the money I have in this engine... I'd rather not switch to a stock B series. Rather than run a 75-80 shot, I'd rather run 6-7 psi and forget about filling bottles.

How would I do this ? I know I can use a thick h/g to bring down the CR... but how low can it go ? Prolly a full point ? I'd still be in the mid 10's ! I figured adding a b16 or ITR head would get me lower still... but the next issue comes to mind... The pistons I have are DOMED... would this cause a big problem with hot spots ?

Can I get some input here ?

Should I just forget it and put the turbo or nitrous money into finishing the n/a build and make ok power ?
Should I spray it ? (Not a big fan of spray)
Should I do what I plan and lower the CR to boost ?

**This is my daily driver and weekend racer... I won't be boosting double digits as a low boost should do the trick for what I want

X2

 

U dont wanna spend money to rebuild it, but if you blow the motor u will have to pay to rebuild it. now your going to get people here saying with a good tune yada,yada. personally I wouldnt chance a high compression motor like that, but thats just me. Im sure u can sell those pistons to help by lower compression ones. might save u from doing it the hard way.

 

I agree with you...

My logic is that if I can get the compression down to about where it was stock 10~ or so... how much would I be taxing the engine with 6 or 7 psi intercooled ? I mean.. the engine was built for nitrous mind you.

(**My block is sleeved btw... if I didn't mention it)

 

You can probably lower it a point or so with somthing like a mr.gasket stackable head gasket-- but that still leaves you at 10.6 to 1. This is going to be a low boost car, likely 10psi or so at most, but a monster across the power band. If you could drop it to 10:1 i'd be really comfortable saying do it, but type R's are around 10.5 or so right...? And people boost stock R's all the time to some good numbers -- so if it's built, and boosted with a smart tune, you'll probably be ok.

Matt

 

get a thick HG and some cam gears to fix the advanced cam timing. if that wont go, swap pistons. not much choices.

 

Guidance...

Same thing I tell my friends. 1) Save the money to do what you want, not what you can afford now. 2) If you can't afford to replace the engine at least once, even if it's just with a plain jane stock replacement, then maybe you shouldn't go the turbo route.

Just my $2/100

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DSF &raquo;</TD></TR><TR><TD CLASS="quote">2) If you can't afford to replace the engine at least once, even if it's just with a plain jane stock replacement, then maybe you shouldn't go the turbo route.</TD></TR></TABLE>

I can easily afford a d16 swap if it comes to that.... so not an issue I've been turbo for some time before and been thru my share of blown motors and keeping the wrong company tuning/building wise.... so if I'm talking about turboing $4k worth of built motor... it means I'm willing to risk it, but not being stupid or wreckless about approaching it.

I already noted I won't want to delve into the 10psi + level of boost on this. I want to run about 6-7psi... for just the reason Johnyquest said... I would love that monster powerband.

What I'd really be concerned with is the engine's ability to run safely with a reasonable lifespan... I wouldn't want to be driving out to the beach on a hot day and not be able to drive up some mountainous road w/o worrying about overheating or pinging, etc...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by X2BOARD &raquo;</TD></TR><TR><TD CLASS="quote">

I can easily afford a d16 swap if it comes to that.... so not an issue I've been turbo for some time before and been thru my share of blown motors and keeping the wrong company tuning/building wise.... so if I'm talking about turboing $4k worth of built motor... it means I'm willing to risk it, but not being stupid or wreckless about approaching it.

I already noted I won't want to delve into the 10psi + level of boost on this. I want to run about 6-7psi... for just the reason Johnyquest said... I would love that monster powerband.

What I'd really be concerned with is the engine's ability to run safely with a reasonable lifespan... I wouldn't want to be driving out to the beach on a hot day and not be able to drive up some mountainous road w/o worrying about overheating or pinging, etc...</TD></TR></TABLE>If looking for only smallish power just put in a lower comp head gasket, swap the pistons if you really want to make good use of the sleeved block, I would personally go with 9:1 c/R pistons and boost the **** out of it.

 

you can boost that comp. with good tuning, or if you want you could throw in a thicker head gasket to be extra safe

 

So plenty people saying it can be done... I kinda know that.

I want input on the long term reliability of daily driving at low boost... no one has boosted an n/a engine sucessfully b4 ?

 

There are plenty of full race turbo motors that run that kind of compression, but IMHO, its not the way to go everyday. You have done so much, and spent so much on the motor, just swap in a set of lower comp. pistons and enjoy the turbo. (You will not be able to keep thet monster @ 6-7 PSI for long) The power of boost is just tooooo addicting!
Hank

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hankish &raquo;</TD></TR><TR><TD CLASS="quote">There are plenty of full race turbo motors that run that kind of compression, but IMHO, its not the way to go everyday. You have done so much, and spent so much on the motor, just swap in a set of lower comp. pistons and enjoy the turbo. (You will not be able to keep thet monster @ 6-7 PSI for long) The power of boost is just tooooo addicting!
Hank</TD></TR></TABLE> W3rD