Turbo power delivery + Track use

[JungleGus]

Hi Fullas

I'm interested in hearing some opinions on my setup and getting some suggestions - (the car is based in NZ and just got back, so have been driving it for a month)

The problem i have is that I am not a huge fan of the power delivery - it's missing the m20/m50 instant low down torque but doesn't have a amazing top end as the turbo runs out of puff. it has a great mid-range (too much for a wet road) but on a dry track it's a tough car to beat.

If I keep it (I might sell it - only problem is despite the turbo its a very tidy E30) then as I see it I have two options:

M52 it (easy enough, maybe do a stroker, or M54 and use the Motec) - nothing too powerful but it would get me my beloved inline six sound and feel

the (possibly easier?) option - re-do the turbo set up
I've got the engine details below (the turbo/intercooler are from a sierra cosworth, so might have some overlap with tuning the YB)- what I am trying to find out if re-doing the project would achieve the goals I am after:

1. more powerful top end/ability to rev (there is no point in me revving her above 5.5-6k now)
2. reliability - the manifold occasionally touches the frame rails which isnt great

what I am thinking is maybe:

tubular manifold to relocate the turbo
bigger turbo
external WG


Engine (M42 1.9L)

Custom intercooled turbo setup.
Mosselman Log Manifold (modified)
Garret T3
JE Forged Pistons, Lowered compression ratio - complete motor rebuild.
Motec M4 ECU, Full electronic engine maps, boost control.
Currently runs about 15psi on 3rd and 4th gear pulls - does boost spike in lower gears

Would be interested to hear opinions/experiences etc

Cheers!
Gus

[oakey]

Seems a waste to start again. I say improve on what you've got. Has to be the cheapest and easiest option surely?

[JungleGus]

that's what i'm thinking - although i do have the benefit of not having paid the ££££ to build the engine (in ££ roughly, i paid £3.5-4k for the car..the build cost about £20k since they went through a few engines in the process) and thus don't have too much emotional attachment

still nailing down a day for the weekend Dave - sorry for being vague, i might be moving house too so not much fun!!! Sunday is looking good though

[GrindCulture]

I'd say keep it turboed, but that might just be my 4 pot wrongness shining through. I'm sure if you improve on the turbo setup you can get more peak power without having to compromise too much on the mid-low end. If it's being used mostly on tracks anyway, surely low down drivability isn't so important?

[Karan]

whats the power output and do you have a dyno graph?

[JungleGus]

i was there when it pulled 160 rwkw (when my friend owned it) and was informed after some tuning the Motec it was 190 ish rwkw - personally i think it's prob around the 170-180 - should prob change my sig!

I don't have a dyno graph handy - might be a bit of hassle to get one as the paper copy is in NZ. will work on it

driveability is another thing though - i don't only drive it on the track. i feel like im having a lot more fun on the road thrashing a 2.5 almost! and not going anywhere haha

[Gunni]

I´m pretty sure your manifold is the problem or at least backpressure
can you provide us with pics of your turbo setup?
Possibly the dimensions on your turbocharger(wheel sizes)

Exhaust size?

[e30_Turbo]

M20 Turbo time

[appletree]

I would have thought you could use a elec boost controler to do what you want.

I was reading a fast ford mag the other day and they fitted one to a sierra cosworth and it totaly flatted out the sudden build of boost and made it more drivable all round.

Have you got a build thread or a few specs and pics of the engine? Be intrested to know what inernals and what cr your on. Dont know how i missed this car!

[drifty325i]

You need to come to the dark side Gus v8 haha.

No seriously your car is AWESOME im a massive fan of it mate KEEP IT!!!.

Id look at upgrading the turbo to a slightly bigger ball bearing unit, higher flowing manifold, and some extra tuning. im sure that will cure things and make it much more drivable.

After driving my car on the track then backing that up with a 480hp turbo 200sx with lag i hated it! iT MIGHT well be faster on the track overall, but no power out of the corners and to much lag on the road it was not great

[JungleGus]

bigger pics;



i don't have the exact wheel sizes, i can't look up the stock sierra specs (t03 i think)
it looks small though!
the manifold is a basic log - could be the problem too
exhaust is 2.5" stainless

EMS is motec, using electronic boost control - it could just be the gauge

would love a v8 riley! corner torque pwns. prefer i6 though

i don't have a build thread since i didnt build it - i will document if i pull her apart

thanks guys!

[oakey]

Looks like a nice neat install
Have you spoken to Ant or any other boost gurus about how to get the most from your current engine?

[JungleGus]

nope, would be great to see their comments. it's a little tough when the car is on the other side of the world to do anything which is a bugger

from what i can find out, the specs on the turbo are:

Exhaust:
.48AR exhaust housing with internal wastegate & standard adjustable actuator (12psi max). Standard Garrett T3 flange. 3 bolt exhaust exit with 64mm internal diameter exit, 95mm between studs.

Compressor:
T3 Compressor wheel with 62mm inlet and 52mm outlet.

[Karan]

wicked install, i feel that the cams may have something to do with your lack of topend but epic midrange, perhaps see a specialist who can profile sopme cams up for you

with that great setup you should be running electronic boost control, ive tried a few and my favourite is blitz dual-sbc spec-r, its a huuuuuuge dual solenoid and will control up to and over 2bar very very steadily, i use this on my silvia and we use it on our 600bhp r32 gtr and it holds 1.5 bar solid with no spike in both cases.

would be interesting to see a dyno map as im sure someone could throw you a few pointers

[Gunni]

nope, would be great to see their comments. it's a little tough when the car is on the other side of the world to do anything which is a bugger

from what i can find out, the specs on the turbo are:

Exhaust:
.48AR exhaust housing with internal wastegate & standard adjustable actuator (12psi max). Standard Garrett T3 flange. 3 bolt exhaust exit with 64mm internal diameter exit, 95mm between studs.

Compressor:
T3 Compressor wheel with 62mm inlet and 52mm outlet.

As you saw Ixer write on E30tech.
I´m going to agree with him that you are infact strangling the engine´s natural ability to breath with backpressure.

The M42 is a NA engine with NA profile cams, you 0.48 T3 is not helping. I would call your setup a great 6-9psi setup. But pushing further then that and your building to much backpressure.

The boost spikes your getting are from the wastegates inability to remove enough pressure to slow the turbo axle down.

If you can find the biggest T3 turbine housing that fit´s your turbine wheel
That should at least let you live on longer with this turbo before you´ll want to get more power ;)
You might also just want to move over to a larger turbo alltogether it will on all accounts make for a nicer safer setup.

[Ant]

turbo looks top be an early style T3 B18 ( 2 WD sapphy ) so there is a 0.63A/R turbine housing available to bolt straight on, wopuld let the engine breath a lot better and would move the effective powerband up the rev range quite nicely.

add in a wastegate with a higher control pressure to cure the boost spikes, once the breathing is better you should find you're able to run more yiming on the ign side too, which would help with spool and HP output.


Minor O/T, I like the turbo damper in the pic, nice too see one fitted

[JungleGus]

thanks guys!! awesome feedback - it's great to have what i thought confirmed (although i have been a longtime reader of e30tech turbo threads haha)

ant - good idea on the compressor housing, would you recommend i change the manifold to a tubular one? its a bad pic but the current log is kinda like the one in the pic below. i also really really need to relocate it away from the frame rails so that i might just have answered that question. good point about the ignition timing - i wouldnt have thought of that one



thanks! i like the damper too, was really happy to see it...although its not as stiff as i would like it def does help.

funnily enough the original owner is trying to get in touch with me about buying it back (much like i am trying to do with my old sport haha)

i got in touch with the original owner of the turbo and the specs are apparently: the turbine housing was a 0.48 A/R, and the compressor housiing was 0.60 A/R

thanks again guys!

[Gunni]

Change the turbine housing first before you do anything else and see what that helps with.

You should see a trend in the fuel table that shows that your VE is dropping in the high rpm´s

[JungleGus]

i've found out it has "special turbo cams" - great, not that helpful! Is it possible to get the specs of a cam by looking at it/measuring?

bigger turbo is on the shopping list!

[Gunni]

You can with a dial gauge mounted to the head.
You have to have a degree wheel on the crank.

Then you rotate the crank and let the dial gauge measure the lope.
take notes every 10-15 degrees to get the profile numbers.
Then you can fill them in to a spreadsheet. And then make the spread sheet draw you
a diagram. Do this for each side,