I'll shortly be building an open decked 2.0 WRX engine aiming for mid-high 400bhp figures and interested in peoples opinions/advice, the plan is to pin the liners, use forged rods and pistons, ported heads, tubular headers, steel head gaskets, ARP bolts etc, also parallel fuel rails, Magnus inlet (possibly) and fmic. I need advice as to which turbo (58mm restrictor) to use and any other mods that I should be thinking of? (apart from buying an STI engine) tia

 

Hi there

Really depends on more factors,but I wouldn't start with Open deck block,Open Deck is OK if you are not thinking go beyond 450bhp,I know few people who run high 500bhp on their OBD blocks for few months and years without the single issue all depends how is engine used and where is used,we have run OBD 2.1 which has been OK,but we are know we will be pushing luck if we will be running on daily basis 500bhp,I would say 450bhp is max there

If you are spending money on pinning and using and getting ported heads etc,I would go rather with CDB(Closed deck block) and Big Port AVCS heads and you have awesome combo,with right pistons and right rods,headstuds I would say 600bhp will be possible

And I would rather build for more BHP,I know right now you want 400bhp,but as I know after few runs you will be wanting more,due this I would build engine which will be OK for more BHP,not just for yours target,I'm speaking from personal experience there

What parts to use,those parts I would use for something like 550bhp+

Pistons: Mahle should be OK,but if you can then get Cosworth
Rods: K1 rods,if budget allows then Carrillo or Cosworth will be best bet
Studs:ARP 11mm or RCM 12mm headstuds or please speak with Alyn@AS Performance about their headstuds
Bearings:ACL or Kings bearings
Genuine gasket kit
Headgasket I would use Cosworth,but this depends on the targeted CR,OE MLS are OK and good too
Modified 10mm oil pump should be OK for yours needs
On heads I wouldn't do anything,but this depends on what turbo are you thinking to run and what boost you are targeting
Inlet manifold I would stick with STI,we are run JDM STI one and we are been very happy with this,but this depends on yours what are you currently running

Hope this helps and good luck there

Thanks,Jura

 

Thanks for the advise, I'd be interested in which turbo people suggest for the spec that I'm planning?

 

Hi there

Really depends on yours target and what bhp are you thinking to run,but if you are thinking to run something like 450-500bhp,then I would probably go down the route of the MDX321T or SC42+,but new Precision stock location turbo should be good choice.

Those turbo are 450bhp rated and if you are thinking to run bit more than that,then you will need to run at least methanol with which you should be close to 500bhp target.

As last please use good makers for headers and FMIC,for headers I would recommend something like GT-Spec or Kakumei or RCM,I know they're more expensive,but they're worth it

For FMIC I would have look on Hybrid(HDI),although we are run Japspeed FMIC at 490bhp without the problems

Hope this helps

Thanks,Jura

 

Should of said that it has to be run on pump fuel. I've already got a Japspeed FMIC.

 

Hi there

Then I would choose like MDX321T or SC42+ or Precision stock location turbo which should be great n 2.1

Japspeed FMIC is not bad FMIC,we are run this FMIC on our wagon at 490bhp,beyond 500bhp I would suspect will or can cause restriction

I an only directly compare Japspeed and Hybrid FMIC,which we are run on our wagon and with Japspeed our IAT/ACT temps has been higher in hot weather,but on other hand with Hybwithour temps has been lower in very hot weather,as I said everything depends on more factors which one I would choose.

Hope this helps

Thanks,Jura

 

Best starting with minimum semi closed deck from STi. And pin that if need/want.


Or just a cdb to start with.

 

That would be ok if I could fine either one at a sensible price

 

What is reasonable price??

And price of overall project

Will be small

 

Difficult to say, was meant to be a budget build

 

There was a ej207 on here a few weeks back needing a rebuild for £350. Long engine

 

I think you need to take a few steps back from turbo selection and go back to block selection.

For a start we need to know EXACTLY what it is you plan on doing with the car, and you also need to be realistic about what it will really be getting used for and how you'll be using it.

The reason I say this is because every aspect of your build comes back to the reality of how it will be used and turbo choice is part and parcel of this.

There's a lot more to it than just bolting a bunch of quality named parts together, which carrillo rods, and what Cosworth pistons are dependant on application.

Now I'm just trying to save you some money in the beginning, sure you can bolt a decent spec engine together and zing it around a track or down the strip, but there's going to come a moment when you realise that it's not quite what it could have been and needs to be built differently because of the application.

Better to pay more attention to that aspect now than regret it later, because it aint cheap.

For a start there's no way I'd throw this sort of cash at an engine with the words Track and Race in mind and start with an odb.

Do it right, do it once.

 

The car will be used mainly for racing in 15 min circuit races with the occasional track day, engine capacity can't be more than 2050cc, inlet has to be less than 58mm and minimum weight of the car with driver is 1250kgs. Are semi closed deck blocks that much stronger than obds? Machining won't really cost me anything hence the idea of pinning the obd that I've already got. This isn't a money no object project and I understand the need for careful selection of parts/speccing hence asking the question in the first place.

 

OK, I'm not an expert on what pistons etc are going to be best for that application, but 15mins at WOT and maybe slightly more on track days given that your probably going to be testing and practicing for races is in reality quite a harsh environment, so you're going to need baffled sump, some decent oil cooling, swirl pot, parallel fuel rails, which in it's self is a reasonable amount of cash, hence my saying that we need to know exactly what it's for.

Beyond that, my advice would be to talk to some engine builders that have experience of building engines for a similar environment and know what works.

The people I would be talking to are Paul Finch re engine spec (posts on here as Motors GT) and ScoobyClinic because these are the top experienced tuners in reasonable traveling distance to me, as well as having all the required experience, facilities, top quality in house mapper and being a nice bunch too.

But there are also others I would use, so you're going to have to do some research and speak to a few.

Richard Henry Motorsport
Engine Tuner
Roger Clarke Motorsport

Are all highly recommended on here by others, but I have not used any of them personally.

 

Ive got a JDM STI short engine here (semi closed deck), I can supply it fully built with nitrided crank, acl race bearings, Williams H beam rods, Mahle forged pistons, new 11mm oil pump for £2000. 11mm arp studs and RCM gaskets would be my choice, they would be +£350. If you can spend a bit more a 2.1 stroker would be even better (£2500). I would leave the heads but make sure they are in good condition, valves, seats etc, I would also leave the inlet manifold as std and leave the porting, but if you could spend some money on cams a set of Brian Crower stage 2 would work well.
There will be many many opinions on whats best to do and there are many ways to achieve what you are after, it's worth speaking to your mapper at an early stage also.

 

My thinking is that a pinned Newage EJ205 obd will be as strong if not stronger than a scdb, thanks for the offer but I build my own engines

 

It's never a budget build lol, I tried doing that, it's all the little bits that soon add up.
I've probably got 5k in engine alone now including ecu etc and looms and so on, all your little sensors etc that you'll end up replacing and silly prices.

I've gone down the route of 44k sti8 bottom end with jdm big port heads, newage coilpack conversion, 11mm oil pump, avcs loom, syvecs, gt spec headers, Harvey uppipe, 3" turbo back etc etc. that's just the aim for around 450hp going into a v5 type r. Oh and I've just about to buy a 6 speed too.

 

It depends on how good the pinning is, if your staying 2.0 it may be cheaper to use a 2.0 cdb if you are paying someone to do the work?

 

Hi there

As above guys suggested you will need have at least budget for that

OBD is not bad,with pinning should be OK too,how strong will be hard to say,I know few guys who running their pinned blocks at fairly high bhp and they never have issue with them,but this I've seen only on 2.5 which are SCBD not open decks,due this I would be bit cautious

I see you are in Brighton,due this I would speak with Neil@Slowboy racing,he build for us 2.1 or 2.35 and both has been awesome engines for us

For spec do you want stick with 2.0 or you would consider 2.1 too ?

2.0L is great engine although with fairly large turbo without the AVCS can be or will be laggier and due this I would have look on AVCS heads or for V6 STI heads which should be OK for yours needs

Regarding the Brian Crower cams I wouldn't use them,if budget allows get rather Kelford cams they're better and price is very similar

Depends on the heads but stock AVCS are great heads,with better cams like I've mentioned Kelford you will have awesome combo

And spec there as previously I've posted what I would use and with budget build I would choose:

Pistons: Mahle
Rods:K1
HG: OEM MLS or Cosworth
Bearings:ACL
Crank: EJ207

Hope this helps there and good luck

Thanks,Jura

 

Well things have moved on, I've stripped the ej205 donor that I bought off of eBay as having a bottom end rattle and found that it had a melted piston but has steel rods and a cross-drilled crank.... BONUS So having saved on buying rods I've now bought a pair of avcs heads complete with Crower cams, double valve springs, retainers and followers at a good price, I'm still undecided as to which block to use but will have to wait and see what comes along .......

 

Assuming no damage to crank and rods?

 

No, just a detonated standard piston, it looks like it had been rebuilt shortly before the piston damage, even the bearings are as new.