Ok, so lets say i have a 2.4L stroker motor, 87mm x 107mm. Max RPM is 8.1K rpm's. Fully ported head, 3angle valves, Ti retainers, Ferrea springs, 272 cams, ARP studded head/rods/mains.
Log style manifold, with a 38mm Tial WG.

Im thinking about getting a GT3071 or GT3076 for it.

My question is, what size AR should i run?
and what trim, with that AR?

So far I was leaning towards a 3076 with a .58AR hotside...but i worry bout it being too restrictive. I want to spool round 4K, but not be stiffling airflow at 7-8K RPM's. One person told me a .8x AR hotside would be better...but im worried about spooling too late (5-6K).

Im looking for stockish like driveability with 350 or 400+ hp...not a 12second 1000hp supra...lol

A guy at RRE told me to get a GT36 with a 1.08AR... but iirc, that wont spool till 6K+.

what you all think?

 

What company sells a 107mm crank that will not send the piston east..?
Your plan is all over the map.

 

3076 with a .82. Will spool super quick, I think that is what you would be looking for.

A 1.06 AR is big and the spool will be pretty late, or at least later than what it sounds like you want.

Mitch Mckee

 

you are not addressing the question, you are just asking questions...

i did not say this is for a 4G...this is for another motor that is very similar. those stroke numbers are off...all i know is that they overbored 1mm. and we are using a 2.4 crank out of another motor. 107mm stroke is an estimate, afaik it could be a 97mm stroke. i havent looked up the specs in a bit.

im thinking about going with a .8x AR.

anyone know what trim is a good trim for 400ish hp?

p.s. thanks magnum for answering my question.

EDIT: here are the specs:

BLOCK: Ecotec LSJ engine 86mm x 86mm, bore x stroke
^1mm overbore from that and we are using the crank from this:
BLOCK: Ecotec LE5 engine 88mm x 98mm, bore x stroke

so i guess overall that would be 87mm x 98mm, and im not going to do math to figure out what the final displacement is...i have too much engineering HW already. I figured that this place is very knowledgeable about srtoked 2L motors with big GT30+ turbos...so i aksed.

EDIT#2: its a 2.303L stroked motor...fwiw.

 

x 10

.82 a/r is the only one you want to think about with your setup.

Scorke

 

^hey man, thanks for your help.

 

i'd do a 1.06 personally

 

Is the 1.06 open? Does the elimination of back pressure really help out the 30R up top?

My .82 A/R on my 2.3 (3076) lost 220 tq from peak to redline, I don't think even that much A/R will help it survive up top, I think this guy wants it down low. If you disagree let me know what you reckon!!!

Scorke

 

^yea, you got it. Im looking for more downlow, without too much restriction up top.

a .53 is great for a reg 2.0, but being a 2.3 it needs more space.

a 1.06 would be great for a larger frame turbo (i.e. a 35R 42R)

if i could rev to 10K, a 1.06 would be great.

 

On my 2.3+.82 3076 on race gas I made 480 ft lbs of tq on c16 at 4800 rpms, it was tourqey as hell, 490 hp up top, a .82 on a 2.4 should be plenty for you.

Scorke

 

You asked specifically about a setup while including misinformation.
I asked questions because only after you answer them can I give you my factual opinion on the matter.
Not trying to insult you.

On a 2.3 liter stroker (on an evo) with a 100mm mitsu crank and off the shelf pistons. Your ideal A/R ratio for the most available torque on a T3 flanged turbo... a .63 will make it very fun and very responsive. An .82 housing will allow more topend, less egt and more exhaust capacity. Problem is space.
On a T4 style turbo, it will depend on if it is on center or tangical. Bottom line, on the street I run a .58 with an open volute housing. On the track I switch to a .81
Hope that helps.

 

can we get an answer on the actual crank and piston size before making decisions on turbo selection as your set is varying a good bit...the 87x107 is actually a 2.55L engine anyhow and your rod ratio would be horrendously short...

 

SoCalRedLine is asking all these questions on my behalf. the engine he speaks of is mine. It is a 2.4L LE5 ECOTEC short block. Bore x Stroke: 88 x 98 mm the compression ratio is about 8.5 : 1 *note the cylinder bores are .020” over sized I’m not sure what that equates to in metric off the top of my head. I have 2 sets of cams as of right now. The set that’s in the motor as we speak are from colt cams they are Stage II tri flow cams heres the specs on the TRI Flow cams. These specs are in standard measurements Note: Primary/Secondary indicate TriFlow Mode.

Specs:
PRIMARY INTAKE
ADV
264* 418L
@.050
209*

SECONDARY INTAKE
ADV
256* 417L
@.050
202*


PRIMARY EXHAUST
ADV
256* 417L
@.050
202*



The second set of cams I have are a copy of the EVO HKS 272 cams. I’m sure I don’t need to give you guys the specs on these cams 

 

Does all this 4G63 talk ranslate to an EcoTec?

 

^well... yes and no. No being that its not the same motor by any means. Bore and stroke are different, but the flow is similar (when you hog out the Ecotec head as much as MVP has). The Ecotec is similar enough to judge turbo size, as in it flows almost as much as a 4g.

Basically this is where i found the most people converting a 2.0L to a 2.4L, and thought it would be the best place to get my questions addressed. I appreciate the help a LOT.

the Ecotec LSJ is a 86x86 at 9.5:1 compression, and 262 cams...produces about 220-230bhp @ 12psi on a supercharger. (think, US Spec Ariel Atom engine...)
The engine we built uses the LSJ shortblock and a modified head that flows 20% more than the stock head, a 2.4L crank, along with longer duration cams (mike, you need to use the HKS 272 cams), should produce round 280-300bph on the stock supercharger @ 12psi.
We also put in forged pistons, and rods, with a CR of 8.5:1 (for our lovely CA pisswater gas.)

We are really pioneering the stroker for this engine, and want to make damn sure it really pulls off good numbers...


So is a 4g an Ecotec motor? not by anychance, but they share many of the same characteristics...max HP on a Ecotec 1800hp, max HP on a 4g 1200hp
Ecotec = aluminum block+steel sleeves+billet steel cranks.
4G = ironblock

now will Mike(MVP)'s car be faster than my 4g?...we'll just have to see