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2001 SRP 2.5RS/RA/SOHC Monster
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One fan is more for the A/C anyways, and if you removed the A/C condenser up front, that already increased the air flow through the radiator significantly.

Could always unplug it and do some runs and test the temps to when in use.
:stupid:
 

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97 WRX STi Type-R
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185 Posts
Discussion Starter #242
One fan is more for the A/C anyways, and if you removed the A/C condenser up front, that already increased the air flow through the radiator significantly.

Could always unplug it and do some runs and test the temps to when in use.
Exactly my thoughts. Wanted to test it yesterday but came back late from work...
I have two-speed override switches for fans, so I will check it and leave the one that has two speeds, because I believe second one only switches on max speed.

I can't cut any metal from chassis according to my class regulations and suspension pickup points may be limited to stock position which questions possibility of using tubular subframe.. But those are nice mods.. I checked once again yesterday and MSI does front tubular subframe with integrated splined sway bar with billet links... Not only it gives 50+ LBS of weight reduction, but also has options for suspension mounting points for lowering. Everything is great except for price ))) Like.... it's just about the same as market price of my whole car )))
 

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97 WRX STi Type-R
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185 Posts
Discussion Starter #244 (Edited)
Went to the track to test the car. Spent some time tuning ECU and quite happy with it now. Boost is up to 1.3 bar although it seems to heat air too much and intercooler can't keep up even on colder day with water spray on..
Anyway, disappointment of the day was the suspension. Our local track has many long slow turns and usually I switch to throttle quite early moving to the inside quite early to minimize trajectory length. Also, being turbocharged, car needs throttle before the apex to have some time to spool the turbo before corner exit. Unfortunately, I just can't put the power down mid corner corner because car lifts inner rear wheel and whenever I apply any throttle it just spins it in the air... As the result, car coasts during long turns slowing down with me trying to balance with throttle and steering to straighten it out where possible to get that tire to the ground.
If I add a bit more throttle, DCCD control kicks in and transmission starts binding directing torque to fronts, but that's usually too much and too late. It helps to run aggressive DCCD maps, but I feel that I need to sort out things in suspension department to ease out life for transmission a little.
I screwed up a bit stiffening rear sway bar on previous trackday and adjusted rear coilovers adding some preload while trying to figure out different stuff with both of these adjustments making the situation worse.. To date I read couple of old(er) threads about this lifting wheel problem and frankly still thinking what approach should I take.
Definitely my springs are on the soft side for my sticky tires but I want to keep them for now and explore the other ways to fix this problem. Also, I read about many cars having same issue with harder springs.

Suspension specs now are:
BC Racing inverted coilovers
5kg/mm front and 4kg/mm rear springs
Whiteline 22 mm front sway bar, 2-way adjustable
Whiteline 24 mm rear sway bar, 3-way adjustable
Whiteline roll center correction and anti-lift kits
"Free caster mod" on front lower control arms
MSI top hats maxed out on adjustment and rotated 45 degrees to provide more camber and caster at the same time.
Rear adjustable track arms + OEM toe bolts replaced with non-adjustable ones.

In the front the plan is:
-sway bar on max stiff
-rotate top hats to max caster position and get as much camber as possible from OEM adjustment bolts
-raise car a bit
all these changes in my theory should contribute to improvement in suspension geometry and roll resistance.

With the rear suspension I need to understand if rear sway bar overpowers soft springs and pulls inside wheel up or I'm just lacking of droop travel. In my opinion it can be both, but considering that now droop travel is only about 25 mm, I will try to check what is the maximum possible and if it will solve the issue. So, plan is to remove all preload from rear springs and maybe lower the rear to reduce roll resistance from the geometry a get more compression travel of outside rear with same spring rates. Sway bar settings are easy to change so I will start with softest one and try it on the test day.

If sway bar overpowers rear springs, probably I can add some preload to help it but it will eventually decrease droop travel, so I will have to disconnect sway bar at all or try a softer one.

I know that without some roll stiffness in the rear these cars don't want to rotate and tend to understeer badly, so this is my biggest concern.
 

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97 WRX STi Type-R
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185 Posts
Discussion Starter #245
Finally I decided to ditch the idea of water to air intercooler setup.. unfortunately..
the plan is to go front-mount with rotated manifold. Got myself a cheap intercooler for testing...

Will try to recreate something similar to Lateral Performance setup in terms of packaging... radiator will have to be moved back a bit, but should be possible..
Quite pessimistic about the performance of this specific one because it looks a bit rough and fin density is pretty low..
at least side tanks look good.. maybe it will be possible to use them with another core.
Will test it today with hair dryer and compare with a stock one ))))
 

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97 WRX STi Type-R
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185 Posts
Discussion Starter #246 (Edited)
Well, got to the track to test new setup.
Got 5.5 degrees of caster on fronts and 2 degrees of camber on all corners, front sway on full stuff rear full soft, and it's still not working. My friend got couple of outside pictures and it's a mess...


With viscous diff in the rear you can guess what happens when I try to drive through long sweeping turns with steady throttle...
Tried disconnecting rear sway bar - feels better, but understeer gets worse.
It seems that it's time for higher spring rates.
Anyway.. with some dampers adjustments and dccd settings I managed to learn to drive around it, but still 1.5 sec from my personal best.
Also at the end of the day I hurt something in engine and it's now sort of misfires but AFRs are very rich... Limped car home, still need to diagnose the problem...
Disconnecting #1 and #3 injectors does almost nothing to idling engine but at the same it works on those two with others disconnected as well, but much rougher.
Afrs at idle are 14.7 with O2 feedback on but with any load it falls below 12.xx and feels weak...
Any thoughts?
 

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97 WRX STi Type-R
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185 Posts
Discussion Starter #247
By the way, intercooler test went great.
I was pessimistic about new one but with 100 deg C hairdryer blowing on full speed OEM intercooler managed to cool that only to 39 C, while new one managed 26.
The measurements where taking after 5+ minutes of constant flow with amient temp at 19 C...
So, looks like improvement.
Of course in real life flows results may vary, but now I'm optimistic about this setup.

Test setup:


 

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Impreza Actual
2001 RS-T
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1,304 Posts
I also have the rear wheel lifting issue and higher spring rates do not help. My car is 2260 lbs and I am way oversprung at 12k F 10k R. I have a suretrac rear so she spins the inside rear like crazy on the long high speed turns. I have no idea what to do.
 

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97 WRX STi Type-R
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185 Posts
Discussion Starter #249 (Edited)
What sway bars do you have?
I think good plated diff should help in any case.
I tuned mapdccd to go almost full lock very early on TPS values, so it helps to transfer torque to the front as soon as possible.
Regarding suspension settings - going softer on rear dampers settings helped me a lot. Further rasing front damping didn't helped much, but I wonder if it helped to raise fronts+rear damping together. My best time was on 15 of 30 clicks in fronts and full soft in the rear. And I would say that while car was definitely lifting wheel it wasn't a problem for a acceleration at this point.
Other than that, probably it's worth to try different spring/sway bar combos with main idea of keeping rears soft so wheels stay on the ground but hard enough to balance front roll stiffness and not to cause massive understeer. Maybe try higher tyre pressures in the rear to loose some rear grip as well..
I'm thinking that source of the problem is weight distribution. Car is front heavy, so you either keep it from rolling with high front roll stiffness but have understeer as the result, or going on three wheels but then you have leak for torque if there are no good diffs to deal with it...
 

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Impreza Actual
2001 RS-T
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1,304 Posts
I have GD WRX front and rear swaybars. I will try softening the rear, I have it pretty hard right now. And yes my F/R weight ratio is horrendous!
 

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97 WRX STi Type-R
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185 Posts
Discussion Starter #251
I believe OEM WRX sway bars are pretty weak compared to your spring. You may try disconnecting rear one though...
 

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97 WRX STi Type-R
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185 Posts
Discussion Starter #252 (Edited)
Also at the end of the day I hurt something in engine and it's now sort of misfires but AFRs are very rich... Limped car home, still need to diagnose the problem...
Disconnecting #1 and #3 injectors does almost nothing to idling engine but at the same it works on those two with others disconnected as well, but much rougher.
Afrs at idle are 14.7 with O2 feedback on but with any load it falls below 12.xx and feels weak...
Any thoughts?
So, lots of stuff happened. I removed cheap injectors I bought and diy-flow tested them to find out significant difference. I hooked up pressure sensor to datalogger to measure compression and got nice graphs.

Cyl 2 and 4 were looking like this:



While cyl 1 and 3 were like this:



Translating those to Bars I got following results:



thinking that injectors ruined my motor I continued with further investigation and found that timing jumped a bit.

Got it back and compression is back to normal!

Since then I upgraded ECU to plugin link g4+ (wrx v3-4), painted and swapped back original 18mm rear sway bar.

Not much done during lockdown in general. Currently I'm waiting for over a month for connectors and some wiring supplies to add all extra sensors to link ECU. And some electronics to make can bus sensors expansion for datalogging.

Anyways, back to "fun stuff". Yesterday I went to track to test updated alignment and suspension setup and just three laps in engine started misfiring violently an tack was jumping all over the place. It was scary, but oil pressure was fine, thrlere were no smoke clouds and strange sounds and engine produced some power, so Iimped car back to pits.

Having proper ECU now I managed to pull the log of the event:



Nothing crazy, 4000rpm, 1 bar of boost and something thew off rpm readings so value started jumping back and forth...

From there I tried to find source of the problem and checked crank sensor - nothing wrong. I recently installed Bosch combined oil pressure/temp sensor instead of OEM pressure switch for dash light, so I had high hopes for this one… On idle engine was barely running with rpm on tach jumping from 1000 to 4000, but when I pulled cam sensor connector it immediately returned to normal idle. I ran trigger scope to confirm that both sensor's signals were good and clear (good ECU is such a cool tool!)

Then I removed timing covers to confirm that LH intake indeed was couple of teeth off.

So… what's wrong? Engine is STI v2, so early 90s. All timing component are relatively fresh - installed 2 years ago and have minimal miles on them. Tensioner is older version but was new. Belt is Gates racing T328RB.

There are no belt guides on crank or cam gears as in newer engines. I plan to replace full timing kit, but Is there anything I can do to older engine to upgrade the setup?

I found that guys from RCM find older tensioner design better design but it lacks one additional pulley that was added with newer design, so they have custom billet bracket to have both, but it's pricey:

https://rogerclarkmotorsport.co.uk/...-grip-timing-belt-bracket-tensioner-idler-kit

Anyway. Timing belt slipping at 4000 is something that is not up to stock performance level, so not sure if I start throwing fancy billet stuff at it…

So, any thoughts?
 

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Uuuuu... another Link ECU on Subaru !!!
Yes.. rpm spikes are usually an idication of cam/crank sensor issues.

So you were running with the wrong timing for the last 2 years ?
 

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1995 EZ30 Coupe
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I was able to install a crank sprocket belt guide on one of my old motors, perhaps you have the bolt holes for it. Nice peace of mind, especially with your woes.
 

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97 WRX STi Type-R
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Discussion Starter #256 (Edited)
So you were running with the wrong timing for the last 2 years ?
No, I just had second event of skipping couple of teeth during the past 6 months. And I only been on track about three times, so it happens alarmingly often. And now I remembered that originally when I removed old timing belt 2 years ago it also was off by a little bit.
Looking again at the screenshot of the log I posted I started questioning if it may be something related to fuel or tune? There is abnormally high spike of injectors duty just before the event, although AFR seems to be normal.
The tune now is still a work in progress an I hadn't touched it in a while due to recent mess with this virus. I remember that before the lockdown I was working with boost control PID, so target boost is conservatively low at 1 bar and boost cut is low as well at 1.4 bar. It may be that I hit a boost cut and timing skipped because of rough cut implementation. I need to open log on my PC and check it out... But previous time I strongly believe that problem with timing was due to fuel starvation in turns and misfires due to fuel pressure drop. That time I felt car lost power and started misfiring right after such thing happened. Fuel starvation starts when I have less than half tank of fuel in right turns. I need fuel surge tank or sonehow move pickup lower, but since it can be fixed by adding fuel this it constantly being delayed. As an easy support until this is done I was supposed to wire fuel pressure sensor to ECU to compensate for small pressure drops and display warnings, but I'm still waiting for crimp tools for expansion connector :(
Initially I didn't thought about it since this time it happened only on third lap in with almost full tank, but looking at the boost log makes me thinking that it might be a boost cut...

Shopping for timing components appears to be tricky :) newer style tensioner with additional pulley can be easily installed with just a bracket swap and sometimes is marketed as an upgrade for older cars. While older style of tensioner with its respective bracket is also sold as an upgrade for newer cars as proven WRC-style solution :)))
Will probably go for new oem timing belt and newer style tensioner to have both setups on hand to choose from.
I also might have newer style bracket on old broken engine.
Next Sunday there will be first time attack event this year, so probably for now I will just reset the timing and check the tune to make sure boost and rpm cuts are safe enough...

Update:
Nope, map limit was not reached and there were no cuts. In fact I can see that boost began to drop moments before rpm value went from 4000 to about 13000 due to sync issue and about second before that there was high noise/knock level on cyl 3-4. (It's wasted spark for now, so knock levels are paired). Unfortunately knock strategy is in early stages of development, so can't even tell if it's real knock or not. Although it matches MAP spike in this instance.
 

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Having separate fuel and oil pressure sensor will help you save your engine.
I do have Defi gauges and since I have a Defi oil and fuel pressure I am feeding the signal into Link ECU.

Its relatively easy to scale it into the ECU with volt meter.

I can take a look at your map and log.
Msg me with links if you want.

Also I've created a engine protection based on AFR's .. so if your fuel pressure drops, AFR's drop and that removes ignition in my case. (5D ignition table)
Its slow.. slower than knock but just another layer of protection.
 

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97 WRX STi Type-R
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Discussion Starter #258 (Edited)
Thanks! Yes, the plan is to have all the sensors in ECU, when I run out of IO I plan to use some CAN extension solution. I already have fuel pressure sensor wired to external datalogger and Bosch combined pressure+temp sensor installed in place of dash oil pressure switch. Now it's matter of getting my order with wiring supplies to get it finished.

I still have old oil pump without bolt holes for timing belt guide on crank pulley. I think of getting a new pump with the guide, is it worth it? Also newer engines have guides on cam gears - are there any ways to install those on older engine?
 

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97 WRX STi Type-R
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185 Posts
Discussion Starter #259
So, now I'm stuck choosing oil pump.. Don't know what is in there right now, but thinking of ordering 11mm.
Greddy t518z oil cooled turbo is waiting, I have a suspicion that this engine has oil squirters as well, so I hope that 11 mm will be fine...
 
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