Had my car remapped today, 326bhp and 319lbs/ft torque which I'm happy with.
I was told with an STi intercooler and TD05 20g, I'd see around 370bhp but my engine has done 99k so I wouldnt expect it'd last long, so I'd be prepared to go down the 2.5 route.

So

Roughly, what bhp and torque would a 2.5 bottom end with my 2.0 WRX heads, 2.5" decat exhaust and a TD05 20g?

 

I'd suggest talking to Paul at Zen Performance but prehaps you have someone closer to home

 

dont think youll make much more BHP with a 2.5, but will get a huge increase in torques though

 

I currently have a VF30
AndyF said with a 20g, I'd see a 40-50bhp increase. I'm just wondering if a 2.5 will make a significant increase above that.

 

yup that sounds about right to me, i have two maps on mine i make around that figure with my 20G on vpower/tesco 99 and then around 400(ish) on the methanol with a higher boost lever

 

What the f@ck does a 400bhp RA pull like????????? Do you need to strap your hands to the steering wheel??????? I can see me selling up and going down your route......................

 

theres mucho fun to be had in my car through the gears lol

 

<<<<<<<< i managed this on my 2.5 with a 16g

300bhp-350lbft at the wheels

it pulls like a ******* and is pretty much lagless

top end is a bit poor mind, but i don't care about that, scoobs to me are punchy cars to sling you from one corner to the next, not big laggy motorway top speed machines

 

I really dont care about top end either. 120mph is well fast enough for me

 

20g is old hat there are much better turbo's out there now for your needs. Granted they are more cash but they spool quicker so it will save you cash trying to reduce your spool

 

price wise for the amount of difference in performance between the 20G and the 321 ill be going with another 20G, granted the 321 has an etrar 30BHP but theres not alot in it with regards to spool maybe a few hundred rpm, is it worth all the extra £££?

 

100% agree ,20g vs 321 on the road (same set up all but turbo) there is very little in it and not worth the extra cash

 

Andy.F mapped two car`s up my neck of the woods a while back, similar cars a Type R and a Type RA both with similar mods as well, here`s his thoughts

To me untill the 321H comes down to a similar price range as the 20G its not worth it

 

On my 2.5 AVCS engine I'm getting 380/380 on the Zen RR with a TD05/20g.
1 bar is at about 2600 rpm and 1.45 just before 3000 rpm.
Power delivery is a straight line to the rev limit
<<<<<----- see my Plus Profile

If the target is isn't into the 400 plus area then the 20g seems to offer more VFM than a 321.

Nick

 

I think both the 20g and 321H are value for money if your mods can support them. At these power levels the difference in price are about £400 and the difference in power is about 30HP, so £400 for 30HP isn't bad returns at the 400HP mark.

Those with cars with a TD05 as OE can get the 20g on exchange which does represent VFM compered to the 321H.

And of course if your car can support 450 HP then if you were going the 321H route, you can have an extra 40-50HP more for no exrta expense with the 321T, the only compromise being spool

 

It is weird Nick because it is a much bigger turbo but I get a better spool up with the MD321V. I reach 2 bar at 3000. Obviously you dont have to run it to 2 bar but 1.5 bar at about 2800 could easily be held to redline if you wanted to limit the power/torque to suit the engine (& clutch) capabilities.

 

fecking hell that is impressive!

 

i am still interested in going down the 20g route on my 2.5 sti
im guessing the guys that have already done this are running uprated internals or am i wrong?

 

nope your wrong, theres loads of cars out there running a 20G on standard internals, mine included

 

so what can definatly be achieved in power terms from the 20g? (without meth) and on stock internals

Would love to have more punch through the revs but was advised that the standard turbo is pretty punchy till 400lbs torque

 

if you can make 400lb/ft of torque with the standard turbo why change it?

on a 2.5 your probably looking at 370/380BHP and around 400LB/FT

 

Std internals - that's why my choice was the 20g.
The 321 looks great for the 400-500 area and Duncans info looks like it has better spool - so long as a std bottom end and basic mods can allow it.

If I had plans to make another step then I'd have had a 321 for now and run it in a detuned state.

nick

 

The 20g power just runs on, without the drop off that can be felt on a VF43. It also doesn't spool up so frantically, making the car feel much more balanced coming out of a corner (for me anyway).
nick

 

RA Dunk, is yours a 2.5?

I'm putting a 2.5 with a 20g in my type r (as soon as my 20g turns up)

It's a stock 2.5 sti bottom end (with cast pistons) cometic HG's, ARP studs and P1 heads with 20g and modified injectors. It'd be interesting to see what people are getting with a similar setup.

I realise the pistons are the limiting factor at the moment but I've spent way too much already!

 

have a look here

https://www.scoobynet.com/plusprofile.php?u=38868

 

mine is still a 2.0L, i thought the STi had forged pistons though , isnt it the rods which are the limiting factor on STi engines, maybe im getting mixed up here though

 

std 2.5 (new age sti) has cast pistons unfortunately. The rods and crank are stronger than classics though as far as I'm aware.

I was tempted to go for pistons but I bought the engine built up and it would have been another £700 or so (probably end up more) to fit forged pistons once I'd bought new gaskets and cambelt etc.

I'll be happy with over 350bhp in a type r though I reckon, I think 370bhp-380bhp is supposed to be safe on that bottom end and that would be great.

 

I should mention that with the stock 2.5 pistons, you seam to be limited a little bit to how much boost you can run.

some people say 1.6bar is ok, some say 1.5bar is the limit, some say 1.65bar is crazy, etc etc

 

My 2.5 runs 1.6 bar but thats on cp's, I think you could go to 1.7bar on the 20g with suitable pistons on a 2.5 but not much more. I havnt had mine on a rolling road but my mapper tells me its fueling for 420 bhp so you could safely say its the higher 300's.

 

my 2.5 is making 380lb/ft of torque and 353bhp, loads of torque, loads of fun