'98 Cobra Transformation!
- Thread starter Turbo98
- Start date
Well, I got the car back after quite a while. It seems the car is “untunable”, lol. He did his best but it’s still not right. It’s mainly the idle. It wants to die when going into gear but once in gear, it drives pretty good. Throttle response is instant.
While it was there, my brand new Precision 6266 journal bearing turbos gave up the ghost. The car started smoking when I was there actually. Pulled the filters off and tons of shaft play. I sent them back to Precision and they said it looks like oil starvation. I’ve had two sets of journal bearing turbos on it previously so who knows. They cut me a break on upgrading to their dual ceramic air cooled ball bearing variety so I took them up on it. They have a built in oil restrictor and after this ordeal, the less oil the better.
I’m not sure what exactly is causing it to die when putting it in gear. The converter appears to be pretty tight which may be causing part of the issue. Heck, this car will drive itself onto a trailer at 800 RPM’s without touching the gas! Another thing is that this engine is so strong even at idle. I believe the intake manifold and the way we set it up are simply causing a lot of power down low. I know that sounds stupid but the engine pulls so hard at 800 RPM’s it’s like a bull in the starting gate. The combo is also very different and I believe it’s beyond the limits of the stock ECU. But I gave it a try. I’m not sure if the BB turbos have much to do with it but these turbos spool so fast it’s unreal. The bottom line is that I will now be installing a stand alone first before doing anything with the converter.
At any rate, here’s a short clip of how the turbos behave. This is 10 PSI.
98 SVT Turbo Cobra In-Car 10 PSI, 4R70W, E85 - YouTube
While it was there, my brand new Precision 6266 journal bearing turbos gave up the ghost. The car started smoking when I was there actually. Pulled the filters off and tons of shaft play. I sent them back to Precision and they said it looks like oil starvation. I’ve had two sets of journal bearing turbos on it previously so who knows. They cut me a break on upgrading to their dual ceramic air cooled ball bearing variety so I took them up on it. They have a built in oil restrictor and after this ordeal, the less oil the better.
I’m not sure what exactly is causing it to die when putting it in gear. The converter appears to be pretty tight which may be causing part of the issue. Heck, this car will drive itself onto a trailer at 800 RPM’s without touching the gas! Another thing is that this engine is so strong even at idle. I believe the intake manifold and the way we set it up are simply causing a lot of power down low. I know that sounds stupid but the engine pulls so hard at 800 RPM’s it’s like a bull in the starting gate. The combo is also very different and I believe it’s beyond the limits of the stock ECU. But I gave it a try. I’m not sure if the BB turbos have much to do with it but these turbos spool so fast it’s unreal. The bottom line is that I will now be installing a stand alone first before doing anything with the converter.
At any rate, here’s a short clip of how the turbos behave. This is 10 PSI.
98 SVT Turbo Cobra In-Car 10 PSI, 4R70W, E85 - YouTube
Beast!!!!!!!!!!!!! Evil, wicked, mean, nasty and every other adjective you can think of!!!!!!!!!!!!
That thing sounds so angry! Hope you get it sorted out, can't blame you for wanting to try to get it tuned on the stock ECU, but I guess you can take it as a compliment from your ECU that you built something too badass for it to control 
I bet your neighbors love you! lol
I bet your neighbors love you! lol
sounds like the converter is wayyyy too tight. what stall is in it now? i tried going back thru' the thread didnt see anything after a few pages.
sizing a converter will be hard without at least having a dyno plot showing the torque curve and knowing the rpm range. theres a ton of things to consider too. at any rate, the car shouldnt be driving itself on to trailers. that could lead to a dangerous situation down the line. be careful!
ive enjoyed this thread so far. thanks for sharing with us.
Thanks guys. Yeah, my neighbors probably aren't too fond of me doing this. But it's not too often...
I think it's dawinng on me that the converter is just too tight. Chris at Circle D is really good so that is what kind of surprises me. But I bought the trans through Darrin at BC and gave him the dyno graph to forward to Chris. So something could have happened in that commication chain, IDK. Based on the code off the converter and in talking to Chris at Circle D, he suggested going two steps higher on the stall which will add about 500 RPM's to it. I think the car will still be fast (maybe faster). I think the one in there now is supposed to be rated at around a 2800-3000 stall. But in another car, maybe it would be ok. It's just pulling way too hard at idle. It's tricky like you said.
I think it's dawinng on me that the converter is just too tight. Chris at Circle D is really good so that is what kind of surprises me. But I bought the trans through Darrin at BC and gave him the dyno graph to forward to Chris. So something could have happened in that commication chain, IDK. Based on the code off the converter and in talking to Chris at Circle D, he suggested going two steps higher on the stall which will add about 500 RPM's to it. I think the car will still be fast (maybe faster). I think the one in there now is supposed to be rated at around a 2800-3000 stall. But in another car, maybe it would be ok. It's just pulling way too hard at idle. It's tricky like you said.
Updates?
Bad. Ass.
Haha, thanks guys. Well, there are faster cars. I guess we'll see how it turns out after all these changes are made and it's finally the way I want it. It sucks all the pictures came down. I'll repost some of them on the new hosting site soon.
Well, I have made and am still in the process of making some extensive changes to the car. Along the way, am cleaning up a some of the wiring and cleaning up the engine bay. The intake is back on but not buttoned up yet. I thought I'd throw up a couple progress pics.
I'll post up more pics soon.
I'll post up more pics soon.
that looks amazing!!!!!!!!!!!
So sick ! What are you doing to it
I'm installing a stand alone ECU in it. In doing that, I got rid of the HKS boost controller and AFX wideband. I installed an AEM wideband because I needed a round gauge now. Installing a custom type battery box in the trunk. Also made some changes to the cooling system with the smaller expansion tank. But the main thing is the stand alone which leads to re-doing a lot of the wiring in the car.
Thanks!
Oh, one of the best things is no more MAF. So I made up a custom charge pipe to the t-body and was able to eliminate several silicone couplers and clamps.
Thanks!
Oh, one of the best things is no more MAF. So I made up a custom charge pipe to the t-body and was able to eliminate several silicone couplers and clamps.
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