90stang5speed Rear Mounted Turbo Project Thread
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He did that first. His gaps were down as low as .026 I think. Then he upgraded the turbos & went to an open 3" exhaust with no cats & a straight throught muffler. It doesn't sound like a ricer fart can at all. It sounds almost like a V8 muscle car. the compressor surge & misfires went away after that.
I have been too short in some of the information I have provided. Once you are up and running, have a good tune, have maxed out your possibilities, have access to a g-tech or track time try it. I wouldn't even consider it until your consistent time wise(et) and provided you still have your old ones and can do it for free, or on the cheap. Same with a cam swap now. Info only.
The exhaust gasses want to go back into the motor ,it called reversion.
Too radical of a cam and you can blow boost out the exhaust(overlap),or let spent gases back in, causing detonation. This especially happens before full boost, once the wastegate opens you are ok.
This is the same reason the 114 cam lobe is better than you 112 lobe center line cam. Go to the Weiand website and look @ the blower cams, or nitrous cams,114-116 lobes to keep valve events tight and build cylinder pressure, making(especially a rear mount) spool faster.
The exhaust gasses want to go back into the motor ,it called reversion.
Too radical of a cam and you can blow boost out the exhaust(overlap),or let spent gases back in, causing detonation. This especially happens before full boost, once the wastegate opens you are ok.
This is the same reason the 114 cam lobe is better than you 112 lobe center line cam. Go to the Weiand website and look @ the blower cams, or nitrous cams,114-116 lobes to keep valve events tight and build cylinder pressure, making(especially a rear mount) spool faster.
Another reason to run tight lobe centers, like 116-118.Most cam companies either don't have access to that type of lobe, or don't get the reason to do it.
It IS the opposite of a N/A car for sure. You need more in and out on them, and both valves open help draw in the fresh charge. If used in the rear mount set up massive amounts of hot spent gas backs up to the motor, It would be easier to go back into the motor than spool the turbo.
Someday call Bullet Racing cams and tell them you have a rear mount set up and see what they said.
They were the only company that figured it out ever.
At 1st it was speculation on my part, then after 5-6 custom grinds I could see the benefit. Beware that a 114 and higher lobe will run out of steam and not tach to 8,000 , but you shouldn’t need to if you are @ full boost around 2500 to 3000. The less compression your combo has, the more overlap, the bigger the turbo, the longer it will take to boost.
You do have a dam big turbo!(for a rear mount). Depending on the trim, your 76 in your configuration is good for 850 to 1000 hp. On smaller engine combos, below 6.0 I usually would run smaller twins.
The a/r's are tinny on the rear mount turbo's compared to even a small 4cyl Honda front mount. You may decide to go smaller or larger on the A/R to help tune the boost in to a usable rpm for your combo.
I hope this helps.Yep, its controversial but hey, you got a rear mount set up that is controversial to begin with.
Hang in there and keep up the good work.
It IS the opposite of a N/A car for sure. You need more in and out on them, and both valves open help draw in the fresh charge. If used in the rear mount set up massive amounts of hot spent gas backs up to the motor, It would be easier to go back into the motor than spool the turbo.
Someday call Bullet Racing cams and tell them you have a rear mount set up and see what they said.
They were the only company that figured it out ever.
At 1st it was speculation on my part, then after 5-6 custom grinds I could see the benefit. Beware that a 114 and higher lobe will run out of steam and not tach to 8,000 , but you shouldn’t need to if you are @ full boost around 2500 to 3000. The less compression your combo has, the more overlap, the bigger the turbo, the longer it will take to boost.
You do have a dam big turbo!(for a rear mount). Depending on the trim, your 76 in your configuration is good for 850 to 1000 hp. On smaller engine combos, below 6.0 I usually would run smaller twins.
The a/r's are tinny on the rear mount turbo's compared to even a small 4cyl Honda front mount. You may decide to go smaller or larger on the A/R to help tune the boost in to a usable rpm for your combo.
I hope this helps.Yep, its controversial but hey, you got a rear mount set up that is controversial to begin with.
Hang in there and keep up the good work.
The more boost and compression, the more spark you need. Higher boost levels, even higher compression will "blow" the spark out.
The big boys always use a capacitive discharge system, like Msd-7al.
Nitro cars use a magneto for similar reasons.
Did the vr4 increase the boost levels?
Thanks Loftus for trying to clear that up a little. I want to do a DART block in the future & will probably do a custom cam with that. As for the VR4, yeah he upped the boost to 25 PSI & sees it regularly. I don't plan on RPM higher than 6500 on the stock block & maybe 7000 with the DART so the wider separation of the lobes shouldn't be a problem then I guess. Sorry I don't have more pics. Been doing house maintenance. BLAH.
HotFox
15 Year Member
Obviously the yellow car seriously intends to compete in a legal class of competition. TWO of those deadly turbos( 
) encased in what is clearly light ga. steel w/aluminum tops. w/ the cold sides both hangin' outside of the aluminum boxes. I'd follow this car if I were you 90stang to see if he encounters any difficulty getting passed through tech. For those concerned that your 1/8th steel plate isn't adequate, or just plain dangerous, this may be the model to quell those concerns. I spoke w/ one of my friends still currently in the circuit and he said that you'll see a bunch of this starting to show up next year as these guys attempt to balance the considerable weight of (2) 88-101 mm turbos by getting it off the front end of the car. This whole damn car reeks of cool, obviously pro-built.
Love his side intake.
Bet you didn't know that you were on the front edge of a trend, did you?
) encased in what is clearly light ga. steel w/aluminum tops. w/ the cold sides both hangin' outside of the aluminum boxes. I'd follow this car if I were you 90stang to see if he encounters any difficulty getting passed through tech. For those concerned that your 1/8th steel plate isn't adequate, or just plain dangerous, this may be the model to quell those concerns. I spoke w/ one of my friends still currently in the circuit and he said that you'll see a bunch of this starting to show up next year as these guys attempt to balance the considerable weight of (2) 88-101 mm turbos by getting it off the front end of the car. This whole damn car reeks of cool, obviously pro-built.Love his side intake.
Bet you didn't know that you were on the front edge of a trend, did you?
This is in the top 1-2 cars I have ever seen built with a rear mount outside if the STS shop.
Note how the wastegate is @ the bottom of the bend on the pipe, just the way you would want it.
The exhaust pressure will help push the wastegate open and allow it to work very efficiently. Neat set up and use of the water to air intercooler too.
Great picks and work quality. Rick 91 gt is right, top notch.
Still, my hats off to 90stang5speed for a great build ,thinking outside the box, especially for doing it all outside in the driveway.
Note how the wastegate is @ the bottom of the bend on the pipe, just the way you would want it.
The exhaust pressure will help push the wastegate open and allow it to work very efficiently. Neat set up and use of the water to air intercooler too.
Great picks and work quality. Rick 91 gt is right, top notch.
Still, my hats off to 90stang5speed for a great build ,thinking outside the box, especially for doing it all outside in the driveway.
I allways wanted to build a 69 fastback and have bigger side scoops for the turbo's......
My adrl buddy was allways on the fence about the rear mount set up. He could't see how to build boost off the line.
This is just a crazy idea, but check out the new BD diverter valve set up for turbo's.
Could it be used to build boost off the line? I dono. That's why you hear the poping and banging builds boost(and kick the crap out of the turbo).
The BD set up is for the diesel twin turbo market, but what if ?
http://www.dieselperformance.com/newsletter/Track_Master_Divertor-_10-28-2010.pdf
My adrl buddy was allways on the fence about the rear mount set up. He could't see how to build boost off the line.
This is just a crazy idea, but check out the new BD diverter valve set up for turbo's.
Could it be used to build boost off the line? I dono. That's why you hear the poping and banging builds boost(and kick the crap out of the turbo).
The BD set up is for the diesel twin turbo market, but what if ?
http://www.dieselperformance.com/newsletter/Track_Master_Divertor-_10-28-2010.pdf
With out a doubt, that is a Bad A** car! I would love to have done a twin set up like that but this single is braking the bank as it is. Maybe in the future
. I wanted to leave the compressor side out of the box like they did but with all the concern for safety I decided to box it all in. I think what I might do after seeing that is build a divider wall between the hot & cold side but keep it all enclosed under the box I have now. It feels good to know Im not the only one to pull this crazy idea. It's sucking the originality out of it though lol. Still an awesome car. I hadn't seen all these cars at the time. I wish I had, copying the idea would have been easier than trying to figure it out.
. I wanted to leave the compressor side out of the box like they did but with all the concern for safety I decided to box it all in. I think what I might do after seeing that is build a divider wall between the hot & cold side but keep it all enclosed under the box I have now. It feels good to know Im not the only one to pull this crazy idea. It's sucking the originality out of it though lol. Still an awesome car. I hadn't seen all these cars at the time. I wish I had, copying the idea would have been easier than trying to figure it out.
BK_CAULEY
it's built for speed not longevity, woman
I agree but, the more I look at that twin set up, the more it makes me want to flip my turbo around & route it in a similar way. I can see a few benefits to doing it their way and only 1 disadvantage. That is a pure track car I'm sure. Mine will see street time & maybe some 500 mile trips to KY. I need to be able to run an air filter when not at the track. my setup leaves more room for a filter box. They have two 90* bends for the air intake where my single setup will be more of a straight shot. I doubt that will make much difference though. I Really like their setup. I will most likely finish what I have started but, if I ever go twin, I might have to copy that.
I didn't want to run the risk of sucking some road debris in through the side scoop and damaging the turbo. Eventually that debris would make it to the engine & tiny pieces of grit inside the cylinders would be a bad thing. Even at the track for just a 1/4 mile I will probably use that screen idea so I don't suck in something.
Something I dont know why no one makes is a universal inline air filter that could be made in different sizes, 2 1/2", 3", 4", etc. Almost like a panel filter but round and can be placed in the middle of two pipes. Someone could make a lot of money off that I think, and that would be perfect for what you're doing.
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