4k GT86 Gets a Rocket Bunny Kit & LS3 V8 Swap!
Discussion
So it's been a few weeks and i've got another update!
The Car is back at my parents which is convenient and safe enough (I still need to buy it a decent car cover or carcoon or something!) but working out on a drive way is a bit of a pain when my jack is so bad, definitely need a new one!
Anyway so I finally got to the bottom of why the car was running so badly, stalling, failing to start, etc and it was all down to the MAP (manifold pressure) signal being unreliable.
It became quite apparent when I finally got my head around the Haltech logs and found this interesting area in the logs. Pictured here is when the car stalls totally on its own from an idle, you can see moments before the RPM's drop the Manifold pressure (And the fuel load, which is based on manifold pressure) just totally drop. The fact they're also a totally flatlined value is suspect as well but the bigger issue is of course the MAP value just falling off the face off the earth which pull fuel and the engine just dies.
Now how did we get in to this position... well.. previously I had to chop the MAP sensor connector off of the Haltech harness as it was for an LS2/Gen 3 style sensor rather than the LS3/Gen 4 style i'm using. I admit back then I didn't have my brightest moment as I wired up the new one purely guessing which wire goes where based entirely on the colours!
Eventually I got it the right way around but in the multiple attempts I had lost alot of the excess wire in the harness/pigtail I had and so even when it was correctly wired the ground signal was not good enough and would lead to this sort of tempremental and fluctuating behavior.
So I ordered a new Pigtail connected to re-do it all properly and solder it up from scratch!
While I was waiting on that to arrive I decided to take off the rear section of the exhaust to attack those exahust tips with an angle grinder. I was really quite worried about making a total hack-job of it and what sort of monstrosity i'd be left with but they simply had to go!
Making a line was quite simply running a set of calipers with a pen taped to one side around the existing edge copied the angle of the tips to the new line and then it was just a case of buzzing them off!
I cut off quite a bit but... i'm quite surprised to say the cuts weren't too bad, they needed alot of cleaning up but, i'll let the results speak for themselves!
I'm quite chuffed with that! they're straight, smooth and even symmetrical, a huge relief!
With that I sorted a small oil leak on from the passenger's side rocker cover which was causing quite a bit of smoke as it burnt off on the exhaust manifold, wrapped said exhaust manifold so they were atleast identical both sides, fitted a little catch can for the rocket cover breather and finished off by re-wiring that MAP sensor for hopefully the final time!
With this it feels like the project is "complete". Now all that's left is to take it out on a couple of test drives and get it tuned eventually. I'm going to drive it about before then as it's driveable enough but you have to drive around its low-RPM stutters or bucking, I'll be collecting logs and letting the tune self-learn to an extent to iron some of that out so with every mile it travels it should become nicer and nicer to drive hopefully!
Now we can just appreciate the completed (and cleaned!) engine bay.
Got my name down for the PHSS at MBW in March so fingers crossed i'll be there, in this!
The Car is back at my parents which is convenient and safe enough (I still need to buy it a decent car cover or carcoon or something!) but working out on a drive way is a bit of a pain when my jack is so bad, definitely need a new one!
Anyway so I finally got to the bottom of why the car was running so badly, stalling, failing to start, etc and it was all down to the MAP (manifold pressure) signal being unreliable.
It became quite apparent when I finally got my head around the Haltech logs and found this interesting area in the logs. Pictured here is when the car stalls totally on its own from an idle, you can see moments before the RPM's drop the Manifold pressure (And the fuel load, which is based on manifold pressure) just totally drop. The fact they're also a totally flatlined value is suspect as well but the bigger issue is of course the MAP value just falling off the face off the earth which pull fuel and the engine just dies.
Now how did we get in to this position... well.. previously I had to chop the MAP sensor connector off of the Haltech harness as it was for an LS2/Gen 3 style sensor rather than the LS3/Gen 4 style i'm using. I admit back then I didn't have my brightest moment as I wired up the new one purely guessing which wire goes where based entirely on the colours!
Eventually I got it the right way around but in the multiple attempts I had lost alot of the excess wire in the harness/pigtail I had and so even when it was correctly wired the ground signal was not good enough and would lead to this sort of tempremental and fluctuating behavior.
So I ordered a new Pigtail connected to re-do it all properly and solder it up from scratch!
While I was waiting on that to arrive I decided to take off the rear section of the exhaust to attack those exahust tips with an angle grinder. I was really quite worried about making a total hack-job of it and what sort of monstrosity i'd be left with but they simply had to go!
Making a line was quite simply running a set of calipers with a pen taped to one side around the existing edge copied the angle of the tips to the new line and then it was just a case of buzzing them off!
I cut off quite a bit but... i'm quite surprised to say the cuts weren't too bad, they needed alot of cleaning up but, i'll let the results speak for themselves!
I'm quite chuffed with that! they're straight, smooth and even symmetrical, a huge relief!
With that I sorted a small oil leak on from the passenger's side rocker cover which was causing quite a bit of smoke as it burnt off on the exhaust manifold, wrapped said exhaust manifold so they were atleast identical both sides, fitted a little catch can for the rocket cover breather and finished off by re-wiring that MAP sensor for hopefully the final time!
With this it feels like the project is "complete". Now all that's left is to take it out on a couple of test drives and get it tuned eventually. I'm going to drive it about before then as it's driveable enough but you have to drive around its low-RPM stutters or bucking, I'll be collecting logs and letting the tune self-learn to an extent to iron some of that out so with every mile it travels it should become nicer and nicer to drive hopefully!
Now we can just appreciate the completed (and cleaned!) engine bay.
Got my name down for the PHSS at MBW in March so fingers crossed i'll be there, in this!
Woohoo, can't wait to see this now at MBW! Hopefully you're free on the 12th August to come to our 25th anniversary party in it too 
https://www.pistonheads.com/news/general-pistonhea...
https://www.pistonheads.com/news/general-pistonhea...Cheers for the kind words all! Very much hoping to show it off at the MBW PHSS but I would preface by saying don't expect too much 
it's booked in for Tuning in late april (on my birthday no less, being the earliest date available) so run's like a dog's dinner currently but i'm just chuffed enough it moves under it's own power!
it's booked in for Tuning in late april (on my birthday no less, being the earliest date available) so run's like a dog's dinner currently but i'm just chuffed enough it moves under it's own power!Ben Lowden said:
Woohoo, can't wait to see this now at MBW! Hopefully you're free on the 12th August to come to our 25th anniversary party in it too https://www.pistonheads.com/news/general-pistonhea...
Absolutely going to make it to the 25th Party! Actually held off holding my brother's stag do on that weekend just so i could attend https://www.pistonheads.com/news/general-pistonhea...Samjeev said:
Absolutely going to make it to the 25th Party! Actually held off holding my brother's stag do on that weekend just so i could attend
Good effort, thank you! We're going to have a dedicated Readers' Cars area, so we'll have a special place for your car (plus many others from this forum) So as I can't seem to take 2 steps forward without taking 1 back... more problems!
...and I probably won't make it to the MBW PHSS, or atleast not in the 86
Went to get it MOT'd on Monday and thought i'd use it as an excuse to drive it around a bit, get some self-tuning done on the fuel map etc. This lead me to discover that the car is getting very hot when coming to a stand still.. issue #1
When I arrived and they got in to the bay it was running strangely lean on one side, decided to poke our head under to see if there was an exhaust leak or such and found a whole host of drippy oil spots both from the Engine issue #2 and Gearbox oil issue #3
Credit to my local garage they were fine with me having a nose around using their pit but decided not to test the car at the time understandably. Finally to rub salt in to the wound I found after all this that when re-starting the car the Oil pressure was reading 0 issue #4
So I really need to investigate a few of these issues. Having had a bit of time to think about, nose around and research I think most of them are down to heat, here's my thoughts:
Issue 1: Cooling issues - Car is fitted with an aftermarket Radiator & Fan shroud/Fans, normally this would be sufficient but the fan shroud unit in question is from Mishimoto which has been put in to question in regards to it's quality and effectiveness. I've never actually owned an OEM Fan shroud unit as when I got the car my original one was understandably damaged. My plan is to buy an original unit and fit this, usually these original pieces are more than sufficient compared to lackluster aftermarket units in most cases. Plus it's a potential cheap and easy fix!
Issue 2: Engine Oil - Not a clue honestly on this one and that worries me! Best case scenario my rocker covers are leaking again, or there's a slight leak from the sump mating surface or such. Worst case scenario it's coming from inside the bell housing/rear main seal and that would be a right f
ker!
Issue 3: Gearbox Oil leak - At first I thought this was leaking out of the Gear stick relocation as from below that appeared to be the highest point where oil was spotted but upon getting to the top of it from inside the car I found oil ontop of it as well! i've since read that when the T56 gets particularly hot it can lead to Oil leaking from the breathing hose further up the gearbox. I need to check this possibility out but if that's the case I should be able to resolve this by simply wrapping/coating the exhaust near the gearbox or perhaps making some heat shielding for the gearbox.
Issue 4: No Oil Pressure - I truly doubt I have no oil pressure at all even with the aforementioned leak as the Sump still has plenty of oil and the car still runs & drives (Drove it 5 miles home! Was not in the mood to mess about having it recovered :Laugh without any issues. I feel the sensor could have died or the wiring for the sensor may have got damaged or even fried! Hopefully this is the case as both are easy fixes and I have a spare sensor I can test this with.
This weekend i'll be diving in to each of these issues and hopefully be able to knock a few of them out but i'm not sure i'll really be able to get them all sorted and the car then MOT'd before next weekend.
...and I probably won't make it to the MBW PHSS, or atleast not in the 86
Went to get it MOT'd on Monday and thought i'd use it as an excuse to drive it around a bit, get some self-tuning done on the fuel map etc. This lead me to discover that the car is getting very hot when coming to a stand still.. issue #1
When I arrived and they got in to the bay it was running strangely lean on one side, decided to poke our head under to see if there was an exhaust leak or such and found a whole host of drippy oil spots both from the Engine issue #2 and Gearbox oil issue #3
Credit to my local garage they were fine with me having a nose around using their pit but decided not to test the car at the time understandably. Finally to rub salt in to the wound I found after all this that when re-starting the car the Oil pressure was reading 0 issue #4
So I really need to investigate a few of these issues. Having had a bit of time to think about, nose around and research I think most of them are down to heat, here's my thoughts:
Issue 1: Cooling issues - Car is fitted with an aftermarket Radiator & Fan shroud/Fans, normally this would be sufficient but the fan shroud unit in question is from Mishimoto which has been put in to question in regards to it's quality and effectiveness. I've never actually owned an OEM Fan shroud unit as when I got the car my original one was understandably damaged. My plan is to buy an original unit and fit this, usually these original pieces are more than sufficient compared to lackluster aftermarket units in most cases. Plus it's a potential cheap and easy fix!
Issue 2: Engine Oil - Not a clue honestly on this one and that worries me! Best case scenario my rocker covers are leaking again, or there's a slight leak from the sump mating surface or such. Worst case scenario it's coming from inside the bell housing/rear main seal and that would be a right f
ker!Issue 3: Gearbox Oil leak - At first I thought this was leaking out of the Gear stick relocation as from below that appeared to be the highest point where oil was spotted but upon getting to the top of it from inside the car I found oil ontop of it as well! i've since read that when the T56 gets particularly hot it can lead to Oil leaking from the breathing hose further up the gearbox. I need to check this possibility out but if that's the case I should be able to resolve this by simply wrapping/coating the exhaust near the gearbox or perhaps making some heat shielding for the gearbox.
Issue 4: No Oil Pressure - I truly doubt I have no oil pressure at all even with the aforementioned leak as the Sump still has plenty of oil and the car still runs & drives (Drove it 5 miles home! Was not in the mood to mess about having it recovered :Laugh
without any issues. I feel the sensor could have died or the wiring for the sensor may have got damaged or even fried! Hopefully this is the case as both are easy fixes and I have a spare sensor I can test this with.This weekend i'll be diving in to each of these issues and hopefully be able to knock a few of them out but i'm not sure i'll really be able to get them all sorted and the car then MOT'd before next weekend.
Right, considerably better news this weekend!
Lets back track and go through those issues I had, and a few bonus ones!
First things first, I wanted to make myself feel better and gave the car a much needed wash! something it's not had for over a year at this point!
Issue #1 - Cooling Issues: Despite the fact Mishimoto rate their fans at a particular CFM value which should be plentiful it's common belief that this rating is done in free-air rather than behind a radiator and thus in practice they're considerably lower performing than expected. I had a couple of options here, one was to replace the Mishimoto fans with a couple of similarly sized SPAL fans, these would likely do the trick but would set me back around £380 for the pair!
In the end I decided to actually pick up a set of OEM GT86 fans for £85, something the car has never had in my ownership and fit those, there's no data on these fans out there but they're plug and play, will fit nicely and most likely over-engineered so a GT86 can do hours of running even in the hottest climate.
Touch wood this seems to have resolved the issue, even when coming to a stop I don't see temps over 104c now before it starts to fall back down with the fans. Of course Summer may bare a different challenge but I may fit an oil cooler further down the line.
Issue #2 - Engine oil leak: Honestly as bad as it might sound this hasn't played on mind much, I can't see any visible leak and it doesn't leak enough that it's actively dripping to the ground when coming to a stop but a few bits just get coated in a light film of oil when driving. I did find one of the Oil filter relocation lines wasn't as tight as it could've been and with the concentration of Oil around this area elected to simply tighten it back up and monitor
Issue #3 - Gearbox Oil Leak: I've not fully gotten to the bottom of this one yet but I have a few theories from thinking it over, my initial response was that it was leaking from the gear shifter relocation as you can see the Red gearbox fluid beading around it here:
After getting to the top of this piece from inside the car I found oil even ontop of it which lead me to believe and further google that at times the T56 can simply weep oil out of its breather pipe which is located further up near the bellhousing and that perhaps heat was causing this.
I wrapped the exhaust that runs near the Gearbox to combat this heat and elected to monitor it.
Unfortunately I need to re-address this a bit probably with paint rather than wrap as i've already scraped and ruined part of it! but the gearbox is still leaking as well anyway, When filling up the lost oil it was still pretty much full so perhaps I thought I had simply over-filled it somehow but further theories and more googling finally lead me to believe it could even just be the rear seal on the gearbox, they can apparently leak from-factory which is pretty poor so for the sake of a £10 part i'll replace it some time soon but will simply monitor further.
Issue #4 - Oil pressure signal woes!: This one was really quite frustrating, after everything i'd faced previously I knew for a fact I didn't have 0 Oil pressure, afterall I could still drive the car and wasn't dropping pistons all over the road!
I first found that the Input wire I was using for the Oil pressure (which ran behind the head of the engine and under the exhaust manifold might've been a bit cooked, you can see it that it had gotten hot enough for the insulation to take on the texture of the wire sheathing!
However after trying a different input, a different sensor, re-wiring things 2 or 3 times just to be sure I still wasn't having much luck, it would simply die mid-drive after about 15 minutes.
In the end I solved the Bonus Issue which was the fact my alternator wasn't charging correctly, now getting a much healther 14v at the ECU rather than 12.6v before seems to have coindentally resolved the Pressure signal issue, it's now far more reliable! the Pressure sensor signal is only 5v so really shouldn't be affected by this but.. ohwell!
Finally with all that said and done it was time to get it MOT'd again, which wasn't without its challenges! The "first" MOT attempt didn't go to well, I took it for a good drive on the way there to get the Cat's nice and hot as I was quite worried about passing emissions - I even went as far as to put on a tune that made the car run a bit lean!
But when going to test it as they were struggling to get a good reading it got hotter and hotter which the car compensated for by chucking more fuel to run richer and safer.. in the end a fail!
After another little bit of driving to run in the self-learning of the tune and properly bleed the cooling system I had another crack and in the end that "MOT Map" was doing me no favours. I stuck back on my normal map and it passed!
And there we have the UK's first road-legal LS swapped GT86
Still going to go easy on it until i've got it to a dyno, much less because it's so uneconomical at the moment it costs me almost £1/Minute on fuel!
but OH BOY is it fun to drive! I'm going very easy with it so far with the fact i've not driven anything more than 100 bhp in over a year, much less anything with more than 300bhp in over 3 years! Having said that, the way the torque comes in though is immense, Torque-y V8 NA power is something else for sure!
Previous cars having been Turbo-charged you'd have to drop it down a gear or two, feel the boost shoot you in to the back of your seat and then you were going too fast but in this you can just roll in to it in 4th,5th or even 6th and it doesn't bog down in the slightest and it's actually shocking how it leaps past 70mph with no effort at all.
Lets back track and go through those issues I had, and a few bonus ones!
First things first, I wanted to make myself feel better and gave the car a much needed wash! something it's not had for over a year at this point!
Issue #1 - Cooling Issues: Despite the fact Mishimoto rate their fans at a particular CFM value which should be plentiful it's common belief that this rating is done in free-air rather than behind a radiator and thus in practice they're considerably lower performing than expected. I had a couple of options here, one was to replace the Mishimoto fans with a couple of similarly sized SPAL fans, these would likely do the trick but would set me back around £380 for the pair!
In the end I decided to actually pick up a set of OEM GT86 fans for £85, something the car has never had in my ownership and fit those, there's no data on these fans out there but they're plug and play, will fit nicely and most likely over-engineered so a GT86 can do hours of running even in the hottest climate.
Touch wood this seems to have resolved the issue, even when coming to a stop I don't see temps over 104c now before it starts to fall back down with the fans. Of course Summer may bare a different challenge but I may fit an oil cooler further down the line.
Issue #2 - Engine oil leak: Honestly as bad as it might sound this hasn't played on mind much, I can't see any visible leak and it doesn't leak enough that it's actively dripping to the ground when coming to a stop but a few bits just get coated in a light film of oil when driving. I did find one of the Oil filter relocation lines wasn't as tight as it could've been and with the concentration of Oil around this area elected to simply tighten it back up and monitor
Issue #3 - Gearbox Oil Leak: I've not fully gotten to the bottom of this one yet but I have a few theories from thinking it over, my initial response was that it was leaking from the gear shifter relocation as you can see the Red gearbox fluid beading around it here:
After getting to the top of this piece from inside the car I found oil even ontop of it which lead me to believe and further google that at times the T56 can simply weep oil out of its breather pipe which is located further up near the bellhousing and that perhaps heat was causing this.
I wrapped the exhaust that runs near the Gearbox to combat this heat and elected to monitor it.
Unfortunately I need to re-address this a bit probably with paint rather than wrap as i've already scraped and ruined part of it! but the gearbox is still leaking as well anyway, When filling up the lost oil it was still pretty much full so perhaps I thought I had simply over-filled it somehow but further theories and more googling finally lead me to believe it could even just be the rear seal on the gearbox, they can apparently leak from-factory which is pretty poor so for the sake of a £10 part i'll replace it some time soon but will simply monitor further.
Issue #4 - Oil pressure signal woes!: This one was really quite frustrating, after everything i'd faced previously I knew for a fact I didn't have 0 Oil pressure, afterall I could still drive the car and wasn't dropping pistons all over the road!
I first found that the Input wire I was using for the Oil pressure (which ran behind the head of the engine and under the exhaust manifold might've been a bit cooked, you can see it that it had gotten hot enough for the insulation to take on the texture of the wire sheathing!
However after trying a different input, a different sensor, re-wiring things 2 or 3 times just to be sure I still wasn't having much luck, it would simply die mid-drive after about 15 minutes.
In the end I solved the Bonus Issue which was the fact my alternator wasn't charging correctly, now getting a much healther 14v at the ECU rather than 12.6v before seems to have coindentally resolved the Pressure signal issue, it's now far more reliable! the Pressure sensor signal is only 5v so really shouldn't be affected by this but.. ohwell!
Finally with all that said and done it was time to get it MOT'd again, which wasn't without its challenges! The "first" MOT attempt didn't go to well, I took it for a good drive on the way there to get the Cat's nice and hot as I was quite worried about passing emissions - I even went as far as to put on a tune that made the car run a bit lean!
But when going to test it as they were struggling to get a good reading it got hotter and hotter which the car compensated for by chucking more fuel to run richer and safer.. in the end a fail!
After another little bit of driving to run in the self-learning of the tune and properly bleed the cooling system I had another crack and in the end that "MOT Map" was doing me no favours. I stuck back on my normal map and it passed!
And there we have the UK's first road-legal LS swapped GT86
Still going to go easy on it until i've got it to a dyno, much less because it's so uneconomical at the moment it costs me almost £1/Minute on fuel!
but OH BOY is it fun to drive! I'm going very easy with it so far with the fact i've not driven anything more than 100 bhp in over a year, much less anything with more than 300bhp in over 3 years! Having said that, the way the torque comes in though is immense, Torque-y V8 NA power is something else for sure!
Previous cars having been Turbo-charged you'd have to drop it down a gear or two, feel the boost shoot you in to the back of your seat and then you were going too fast but in this you can just roll in to it in 4th,5th or even 6th and it doesn't bog down in the slightest and it's actually shocking how it leaps past 70mph with no effort at all.
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