I've been looking into engine builds and would like another engine built. Im looking at a reliable 400 withh all the available torque. Would like torque lower down. Now I know for this you need a higher compression ratio maybe 9:0.1? And also a lot of boost but I want to know what block would be ideal to use to do this and what studs and what size, also what size headgasket?

For example I know open deck may not be a great choice so might go for semi closed but would a open deck fully forged 9:0.1 CR ratio with arp 11m studs be able to run 1.8-2.0bar off boost? And not too damaging on the timing etc?

 

Bumppp

 

Hi there

Have look on those two threads

http://bbs.22b.com/forums/showthread...ow-compression

http://bbs.22b.com/forums/showthread...ression-ratios

Hope helps

Jura

 

Sort of helps but doesnt directly answet my question lol need to know what I need to run a 9:1 CR and high boost. Around 1.8-2.0 of boost reliably I know other factors would need to be considered like timing but would like to know what is needed for the build

 

Hi there

We run on our 2.1L with 11mm ARP headtuds,CR has been around 8:5.1,maximum 1.7bar and 25hp shot of NOS without the issue

Jura

 

Open deck block?, whats your spec jura

 

Yes open deck block,we are made 490bhp on V-power and 20% meth without the NOS

Spec has been this:

Cosworth pistons
Manley Rods
ACL Race Bearing sets:big end and main bearing set
Cosworth baffled sump
10mm Modified Oil pump and water pump
11mm ARP Headstuds
Cosworth Stopper HG
79mm Subaru V8(EJ257) Nitrided Crankshaft
Cosworth timing belt kit

Jura

 

If you are going to run 9.0:1 you will need CDB & 14mm stud conversion with Cosworth gaskets or you risk HG failure. I personally would run about 8.5:1 you could then use a SCDB with 11mm Cosworth studs & gaskets. A 2.1 stroker would be a good option unless you can afford to go 2.35, 2.5 will give the best spool & torque but is the most fragile.

 

Hmm thanks for advice. What about the SCDB with 14mm on 9:0.1 CR? Would that be ok aswel? Scdb are readily available and centre thrust and require less work(i think) so just wondering if that would be ok? Also what size gasket would I need to use?

 

SCDB may work, but 9.0:1 is a high CR & it may take a lot to keep it all together especially if you want to up the power & boost at some point. If you stick to 400 it should be OK but once you get used to 400 you'll want more.

 

Hmm true say, could you run higher CR than 9:0.1 on a CDB or would it be pointless anything over that?

 

Why you want to run 9:0.1 CR on yours?

Jura

 

The gasket thickness will dictate the CR, so some carefull calculations are needed to get this right. Are you building it yourself or using an engine builder?

 

Want much torque possible without going 2.1 or the 2.5 and want the car to rev

 

Engine builder as its too complicated for me lol

 

The builder will calculate what gasket he needs for the CR & advise you on the best set up. Who is going to build it?

 

Havnt decided yet, just wanted advice and ppls views on the setup

 

But if you will go with the 14mm headstuds etc,for this you can easy have 2.1L which can rev(off course depends on valvetrain) and torque,on our at 490bhp/480lb-ft without the NOS

Jura

 

The main question is what fuel your going to run, & if your building an engine you should be building your compression ratio into the build not tweaking it with gasket thickness at the end to suit what you have bought piston & head wise, imo you should run the thinnest gasket available, as they are more durable.

 

Im going to be running v-power low boost on low map and then high boost v-power + 20% meth on 2nd map alcatek. What am I supposed to look at piston wise and head wise for the 9.1 ratio?

 

There are also the cams and valves to consider as these are going to need to be matched to get the torque your after, revier cams tend to produce less torque.

If you want it to rev and have plenty of torque your going to need to go 2.1, and get uprated valve train and cams.

Why the opposition to going 2.1? it's by far the easiest and most proven route to get what your after.

It's all about balancing top and bottom end, just running a higher CR alone will not necessarily produce the characteristics your after, but the 2.1 and cams will.

 

I'd listen to this chap, apparently he knows a thing or two about building engines.

I might even chuck him some bit's to machine and bolt together for me.

 

Well I didnt really want to get into changing heads or cams and you have to use 2.5 crank for the 2.1? I already have a 2.0 crank and didnt really wna start buying more bits lol. Tryna save dosh. Im a tight indian

 

If going 2.1, Wiseco do stroker pistons in 12, 16 & 20cc crowns, head wise if going to Supertech valves over OE they raise the chamber volume by 1 to 1.5cc, it all wants measuring, as with cams your static 9.0 to 1 ratio will be eaten into with larger duration & lift cams, effectively lowering your dynamic ratio.

 

It's swings and roundabouts, more expensive studs and machining plus valve train (which will need sorting to deliver the end result your after) v's crank.

Can you see where this is going.

 

I'd listen to what this guy says, he is one of the best engine builders around & will give you the best advice. I'd let him do the build too, he is highly rated on here & built mine last time.

 

What's the car going to be used for? If its road use and your only after 400bhp then why not just fit a forged 2.5? These already offer bags of torque and if built properly are good for 450bhp

 

Lol I can see where this is going. I dont really want to mess around with my heads. Ive got v6 uk heads, benefit to swithcing to v6 sti heads? Anti lag? Also I want the torque without losing much rev. Car will be used mainly on road but would like to track once or twice a year and dragstrip

 

With 2.1L you will not loose revs,as we run on our one same RPM as on 2.0L

Sell yours existing 2.0L crank and get EJ257 or you can go route of the EJ257 and use 2.0L crank and have in theory 2.35L

Jura

 

I did look Into destroking a 2.5 to 2.33 but was told its not worth it?