What cam to run with stock ECU?

[MrBishi]

I currently have a 3" exhaust and an intercooler and I think it still runs out of go at around 4500rpm.
What cam have people used with success? I am looking to update to MPI one day but for now the stock ECU will have to suffice.

[tmz_99]

what turbo are you running? if you get a different cam the efficiency range of your turbo wont change I believe....

[dirty sanchez]

TMZ-99 is right, the factory cam is good for at least 6000rpm. If it's running out of puff it's not the cam that is the problem, it's likely to be either the turbo or maybe the fuel pump?

[Barney]

sounds like valve float. If you are running higher than standard boost sometimes the valves float.

Replace the valve springs with higher perfromance ones or double springs
visit www.performancesprings.com.au

ASHLY

[SpidersWeb]

I read the Starion has peak power output at 5000rpm.

This matches on mine, from 4000-5000 there is a small increase in power, and when it hits 6000rpm power feels the same as 4000rpm, then you change quickly, and you have equal power, its suprisingly comfy as you don't get any sudden changes to acceleration. If you change at 5000rpm there is a stronger power loss when it hits the 3000-4000 range.

If you are losing power at 4500rpm, like these guys say, something must be wrong.

(TC05@9psi, stock 8 valve)

[StarionChef]

Have you checked all the basics? plugs, cap, coil, leads,filters,ect. If any of these parts are old you wont get good top end.
Strong spark is very important on high boost motors, dont go looking at upgrades until you have it performing strong in standard form

[SpidersWeb]

When I got my Staz, it was a littly shy up top as well so I did fuel filter, Iridium plugs, and 8mm Sparkfire leads + using 96 octane, I got a huge increase in my upper range, so I'd agree with that.

[quest]

my first encounter with the 2.0 sohc starion was abroad in my cousins new car. I remembered him running the digital tach into the red colored bars on most gears. (I too have the digital/analog instrument combo) I was most impressed by this as the motor did it reliably, repeatedly and was the SMOOTHEST 4cyl I've ever experienced, even by todays standards.... fell in luv, and thats what led me to choose it for corolla swaps. Mind u, the motor didn't pull hard up top, but it did certainly rev cleanly to redline - nothing air flow couldn't fix.
Thing that gets me is, why r so many of these motors experiencing this 4500rpm fall off. 2.6 us guys plagued by it too. boosted_one on starquestclub had a 20g/06 on ported stock mani/ 3"/ magna/ standalone/ upgade fmic+ pipes/ 284° cam+ springs... yet still had the 4500 fall off. Went to a header/ t4/ new cam+ degreed/ ported head... problem solved. Never did identify it tho. Then u have guys on 16g pull hard to redline.
I'm really curious about the cause of the dropoff. I'll startoff with bone stock 2.0 and get it to rev like I know it did when new... then start throwing mods at it, one at a time, to see what works from what doesn't. I'm sure this motor has the potential.
Thing I noticed is that in the internet era, the really sharp guys who know the ins and out of these old motors have moved on to other things or don't post on forums. So not a whole lotta solid info available.

[StarionChef]

I feel the fall off is due to poor flow through the head. The head really isnt designed for high power. It is after all, an L300 van head.
My ports have being enlarged to 38mm, though not a huge port job, it seems to rev up fast and pruduce a strong push through to 6500. But thats with a small tco6 11a.

[WANTSOM]

As far as I have been able to glean the turbo/exhaust part of the equation holds them back. ie cant get the gases out as hard as you can push them in.

ie the motor chokes itself up high

[StarionChef]

I'd agree with that, longer runners on the ex manifold would free up airflow

[Barney]

Replace ya Valve Springs

[pcuser51]

:D Wantsom cant agree with that 3inch all the way with mine running a
tc o6 11a full boost by 2.5 up to 5000 alright 5 to 6000 takes for ever
must be the head holding it back if any thing mine needs a larger turbo
to take advantage of the exaust.

[Camotec]

i think wantsom means the exhaust ports and manifold, ultimately your only as strong as your weakest point.

Grind out you zorst side ports and if the stock manifold dosen't want to give more power get a custom ex. manifold made up extractor style preferably. (as cheffy said) maybe even larger exhaust valves to make up for its lack of valves.

I think the cam also plays a part, maybe not give enough duration in the exhaust side lobes at high rpm. just a theory, still haven't heard the results of the people who bought aftermarket cams.

Cheers
Ben

[mrb1]

Quest,
the "fall off over 4500" thing is a stock US 2.6 problem. The 2.0 will rev to 6000 RPM fine (hell factory max power is at 5500 RPM (JA 125Kw at 5500 RPM)).
The L300 MPI manifold will reduce the top end because the runners are a bit long, but gives a lot more useable power "under the curve".
If it will not make power over 4500 something is WRONG.

Anyhow I would recommend the following mod list to everybody:
1) 2.5" or 3" exhaust. (which most everybody probably has by now anyway)
2) aftermarket computer and make sure to remove the airflow meter in the aircleaner.
3) Intercooler
4) MPI later on when you get around to it (and save up!).

cheers.