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I’ve tuned dozens of cars. Ignition timing is ignition timing. If you think there’s something magical about what’s programmed into a stock early 90s ECU, well, I don’t even know why you’re modifying your car.

True statement - Generally hotter cams want a tad more ignition timing at the same mass flow due to many factors. Easiest way to do this with a stock ECU is bump up your base timing a tad. Verify things still work well after you do this (no knock, you actually gained power etc).
If you "tuned dozens of cars" then I'm sure you know what synchronizing the timing is and why is done. You keep ignoring the fact that the ECU uses 10 degrees base timing for its calculations and advancing it is not recommended period. There is nothing magical, just pure facts that you keep ignoring or shrugging off.
 

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If you "tuned dozens of cars" then I'm sure you know what synchronizing the timing is and why is done. You keep ignoring the fact that the ECU uses 10 degrees base timing for its calculations and advancing it is not recommended period. There is nothing magical, just pure facts that you keep ignoring or shrugging off.
I’m not sure why you can’t understand it just adds a fixed value up on whatever the stock timing map would call for. The only “calculations” an early 90s ECU is doing is a simple table lookup based on load/MAP/mass air flow and RPM.

So yes, I get it. I’m thinking you are missing something or maybe just don’t know much about engine calibrations.

Of course the BGB is going to tell you not to have the base timing set to anything but 10 deg, but they’ll also tell you not to put aftermarket cams in your car. Lol
 

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Thankyou for your comments, I'm not sure who to follow, so it will be a trial and error. Ill take it to a rolling road tuner after lockdown.
Any Tuners on here near Bexleyheath, Kent?
 

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3 questions to 3SGE rev1/rev2 owners who have modified there 3SGE engines.

1. Do you have dyno results for the dual manual Gen3 inlet cams setup?

If so what gains did you have based on basic bolt on aftermarket mods - eg. headers, exhaust and induction using stock ECU.

Before I book my car for a dyno run, I am looking to see what torque and BHP figures were gained from owners who have already carried out this modification.
Were there any gains in the mid/higher rpm range? I believe the stock rev limit is set at 7200 rpm.

My original stock baseline rolling road figures were: Max flywheel Torque 145 @ 3400 rpm / Max HP 154.2 @ 6200 rpm. before carrying out the below modifications.

It would be good to see if this dual inlet cam modification brings power into the remaining range up to 7200 rpm.

My current cam setup and bolt on's for reference are below,.
Taken from two Gen3+ 3SGE M/T inlet camshafts
In: 252deg, 9.8mm lift
Ex: 252deg, 9.8mm lift

Port and Polished and skimmed Rev1 head
(OEM MLS gasket, Gen 3 gasket from www.tcbparts.co.uk/)

  • Stainless steel 4 - 1 header (Meant for 5fse fits but needed to modify b-pipe)
  • Mongoose exhaust 2.5 inch / Decat (1990 is legal)
  • K&N cold air filter
  • New spark plugs
  • Magnecor 8mm leads
  • New OEM dizzy and rota from TCB parts
  • Adjustable fuel regulator

2. Someone mentioned that a UK 3SGE Rev1/2 Mr2 engine gained up to 20 BHP (193 BHP total) rolling road graphs were provided also to back up statements, simply by adding an adjustable fuel regulator, running at 43.5 psi without the above cams (with only aftermarket exhaust and an Icon Superchip which did ignition timing only)
Has anyone else added this modification and can you confirm there was an increase in power after?

Facebook Forum reference:
3. If power band continues above rev limit, has anyone overclocked the crystal(s) in the stock ECU?
or see this link. I just over-clocked my car! [Archive] - Toyota MR2 Message Board
Im going to order a spare ecu for testing this out.
 

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With 2x 3sge cams, the intake can be installed straight up (match the cam and cam cap notches) for a 119 deg centerline. Advance 2-3 cam degrees to get it to 115-113 centerline, a little more performance oriented. You'll probably lose a bit of idle vacuum.

For the exhaust side, line the notches up, then pick a spot on the gear and rotate the cam 21 teeth or so. Then you'll need to advance 5 degrees or so to get to a 111 degree centerline.

Every engine is a little different so ymmv
Hi LOs7

It turns out my cams are overlapped too much on my dyno graph, flat and hesitant between 3.2k and 5k. Loads of power after 5.5k to 8k so evidence of reversion.

Fuel and air mixture is all over the place, lean and then a little Rich. I have fitted an adjustable fuel regulator currently set to 43.5psi.

Can you please confirm what way you rotate the exhuast cam to get 21 teeth mark when facing the cam gears?

Im arranging for mechanic to fit ajustable cam gears but would like to check to see if its lines up to 21 teeth rotation. So I need as much advice as possible on this

I have attached a test dyno readout.
The red lines are previous stock dyno results, the black lines are dual inlet cam upgrade (dyno would not run higher due to fuel mixture was all over the place) however on the road it pulls like a train after 5.5k - 7k stock ecu and to 8k on modified ECU. I have a moded the crystal on a spare ecu from 12mhz to 13mhz allowing me to redline at 8k and this behaves the same way on the dyno as stock ECU.

I have a planned drag race in a couple of weeks so I hope to resolve mid power issue by then. Any advices is appreciated.

Thanks

Steve
 

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With that significant a problem in the midrange, I think it unlikely to be the cams.

Rotate the exhaust cam ~21 teeth clockwise then dial it in with acg's and a degree wheel.
 

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With that significant a problem in the midrange, I think it unlikely to be the cams.

Rotate the exhaust cam ~21 teeth clockwise then dial it in with acg's and a degree wheel.
Thankyou L0s7.

Looking at the exhaust timing marks attached on the photo I was sent originaly below, it looks as they just marked 180 degrees and put the cam in upside-down. Therefore its on about 23 teeth.
75155


Im tying to work out advance and retard direction when turning the cam crank as there is mixed information on the forums.

If using normal timing mark highlighted in Blue on my drawing below on exhaust gear, I should rotate cam 21 gears clockwise to land at the green 21 mark on drawing below?

I am arranging for someone to adjust to 21 teeth as below so want to make sure it correct.



75157



Currently I believe the timing is on the red mark, I counted the new marks and it was 23 teeth in the above photo.

Here is an upside down shot of the same drawing, current in timing in red, new timing in theory should be green? Is this correct. If so I will arrange for mechanic to do this when he puts on adjustable cam gears.
75158



Thanks
 
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