Turbo ideas...

[MoparPowa]

Not long after I decided on the fact I wanted a '66 Dart, I decided I want to do forced induction. I went back and forth between putting an SRT-4 engine in the Dart as opposed to the 5.7 hemi I was set on. Now that I've exhausted every avenue of research on the 2.4L turbo, I've decided against it and will stick with the hemi, the road I was already halfway down as is. That said, the hemi in an early a-body is a VERY tight fit, I have only one possibility for shorty headers (outside of custom), and it's not even confirmed they will fit. The SRT-8 jeep headers will fit with a big chunk cut out of my motor mount but I'm not really interested in paying such high prices for factory exhaust manifolds that don't even fit. So... The hemi complicates going forced induction in a couple of ways, it can either be an outrageously expensive roots or twin screw supercharger, or an impossible to route turbo. All that said, I'm starting to consider a rear mount turbo. Can anyone advise on this? I'm going to attach some images of some of the ideas I have. Don't make fun of me, I know they're crudely drawn. Most of these images are borrowed from members with similar (further along) builds as mine(Tincup, Rjsjea, etc.), or product images from various websites. I will be running megasquirt and want to utilize e85 with a flex fuel sensor.

These images were drawn before I looked at my engine today and confirmed that the hotside definitely will not be able to go up where I wanted to run it. both the oil filter, with 45* adapter or not, as well as the alternator are too far in the way and the shock tower is just too close to the engine to have any room. That really only leaves me the option of running the pipe under the passengers side steering rack boot and then up to the turbo which would be mounted into the inner fender somewhat at the top/front/side. I'll try and make a drawing to explain what I'm saying.

Image 1 shows the oil pan I intend to use, a jeep factory pan. Routing of driver's side exhaust to passenger's side via front under the pan up by the rack.

Image 2 is just a view of the shorty headers that *might* fit, maybe...

Image 3 is another view of the crossover pipe routed up on the passenger's side which won't fit. Imagine it run under (ground clearance is a concern) the passengers side steering boot and k-frame.

Image 4 is the y-pipe, also routed up but it kinda looks like it's headed to the steering boot anyhow, so much for 3-d drawing a y-pipe! :sad1:

Update:

Image 5 is an example of the routing of the hotside up to the inlet after passing under the steering rack.

Image 6 is the downpipe, looks to be like I can only fit about 3.5" at the very most here... Thinking this may be a problem...

Image 7 shows possible routing of the cold air intake...

 

[MoparPowa]

Well on the fuel system front this seems to be a possibility. Will run it in a stock tank modified with this. Should be able to just support 600 hp on e85 with 70 psi rail pressure at 13.5 volts. Considering a [ame="http://www.ebay.com/itm/like/261352525847?lpid=82"]boost-a-pump[/ame] as well because of how close the pump is to maxed out at that point and a safety margin would be preferable to leaning out a cylinder. I also probably need to up the rail pressure a little extra to account for line/fitting losses, 58 psi base, 10 psi boost referenced, 5-10 psi lines/fittings possibly? I know with injector sizing you are supposed to run 80% duty cycle to ensure stability and reliability, is this the same for fuel pumps? Seems like it would be but I've yet to see any reference to this rule on the wide variety of fuel pump calculators I've tried.

In the world of turbos I've been re-researching turbo sizing and map reading/plotting. Found this little gem thanks to another forum and after some playing around I have determined that I have no idea if my numbers are anywhere remotely correct. I have no concrete numbers on the VE of the 5.7 hemi and the few that I have found (here or here) just don't add up when I do the math(requiring 14 lbs of boost to make 525 hp, a likely outcome from about 6 lbs of boost based on most dyno sheets I've seen). However, assuming I did manage to somehow have the AIT and VE figures correct, it appears I am in the range of a T76 turbo, not exactly surprising. It also looks like I could go up or down a couple sizes. Anyone have any recommendations on turbo sizing and A/R ratios for the hotside? Since this is a street car I know I don't want the turbo to spool too quickly but I'm not entirely sure what balance I'd like. I do know that I won't be spinning the engine past 6k rpm.

I am wondering about my crossover tube diameter in that unlike most builds I'm seeing I intend to join the primaries before the actual turbo. What's the min/max diameter I should be able to run without increasing backpressure or reducing spool respectively? Same question for the downpipe, looks like I'll only be able to fit around 3.5" until I can split to duals, doesn't seem like it will be a problem based on what I've read but I figured I'd ask the more experienced.

Planning on either 2.76 or 2.93 rear gears which still puts me at an SLR of 10.36 or 10.99 due to my steep first gear of 3.753. With my short tires, 25.7" diameter, I may not end up loading the engine as much as the turbo would respond to in first. My shifts into 2nd and 3rd will both drop me down to around 3500 rpm's though and that should really let the turbo do its work. Cruise would be around 18-2000 rpm's at 70mph depending on the gears.

Check this out, crazy power on a stock block with 100 octane race fuel and very moderate timing. They were confident it would live with 93 as well. E85 has 105 octane and should drop combustion temps by 300+ degrees in addition to allowing for a lot more timing and faster spool due to higher density exhaust flow.

 

[jw97neon]

wow busy typing... you make great points. i am planning on going this same direction with my 65 dart. modern hemi and turbo. if i can not make it work as i plan i am going to go with a pro-charger. on a different forum i found that someone is building a 5.7 block using thikek heads, and 6.4 manifolds swapped. want i have found a truck front cover is what seems best to use. i asked what he was doing and he replied with he is just now trying to figure that out. someone posted a image of a truck cover with no a/c and no p/s. just what i wanted to see. this is the route i will be going as my project is still a couple years down the road to be finished. i now have a direction to go.

here is the picture with the truck cover. either spend money on heads and swap you manifolds or go custom with them. i am planning the custom way due to knowing a few people that build some great turbo manifolds.

 

[blown71duster]

Have you seen the twin turbo kits that mount the turbos low at the rear of the engine. I would think this would be good for a street car and use a good pump such as the turbowerx to pump the hot oil back to the engine.

http://www.powerblocktv.com/episodes/HP2010-02/twin-turbo-dodge-challenger

Turbowerx pump which has good feedback from guys using them.

http://turbowerx.com/Scavenge_Pumps/Exa-Pump/Exa-Pump.html

[ame="https://www.youtube.com/watch?v=3OxlVB5zfLk"]Turbowerx remote oil pump - YouTube[/ame]

 

[MoparPowa]

wow busy typing... you make great points. i am planning on going this same direction with my 65 dart. modern hemi and turbo. if i can not make it work as i plan i am going to go with a pro-charger. on a different forum i found that someone is building a 5.7 block using thikek heads, and 6.4 manifolds swapped. want i have found a truck front cover is what seems best to use. i asked what he was doing and he replied with he is just now trying to figure that out. someone posted a image of a truck cover with no a/c and no p/s. just what i wanted to see. this is the route i will be going as my project is still a couple years down the road to be finished. i now have a direction to go.

here is the picture with the truck cover. either spend money on heads and swap you manifolds or go custom with them. i am planning the custom way due to knowing a few people that build some great turbo manifolds.

Hi jw97neon,

I'm familiar with the truck accessory cover. If I were going to run twins it would make a lot of sense to run the exhaust manifolds forward. However, since I'll be running a single turbo and have to run a crossover pipe anyhow it doesn't really serve me any benefit to dump the drivers side in front of the engine and try to cross between the radiator fan and the serpentine belt. It will be tight enough as is without a 3+ inch pipe. That said, my idea about the routing of the actual hotside pipe to the turbo has changed a little bit after staring at my car for a few hours. Some of my famous 3-d microsoft paint drawings included below should spell out what I'm thinking relatively well.

Have you seen the twin turbo kits that mount the turbos low at the rear of the engine. I would think this would be good for a street car and use a good pump such as the turbowerx to pump the hot oil back to the engine.

http://www.powerblocktv.com/episodes/HP2010-02/twin-turbo-dodge-challenger

Turbowerx pump which has good feedback from guys using them.

http://turbowerx.com/Scavenge_Pumps/Exa-Pump/Exa-Pump.html

https://www.youtube.com/watch?v=3OxlVB5zfLk

Hi blown71duster,

Now that I've really looked over the car and determined that I should be able to pull off a front mount setup I just don't see much point in trying to mount the turbo elsewhere. I did look extensively at these rear mounts a while back (STS, NCTS a.k.a CIS, etc) and even started designing my own but decided to toss the idea when I was contemplating the 2.4L engine (plenty of room up front with an inline 4). I really started contemplating the 2.4L because of how badly I wanted to run something forced induction and how expensive it would be to do a supercharger on the hemi since I clearly wasn't going to be able to fit a turbo up front. I see it differently now and am stoked to have a hemi and a turbo all in the same package. There's no loss, all the low end grunt and drivability of the V8 combined with steeper gears to load the turbo and hopefully the accompanying mpg at cruise. The other outstanding part about the efi hemi and the turbo is that I will be able to design a system that can launch and accelerate the car without blowing the tires off. Thanks to extensive boost control options (open/closed loop, gear-based, etc) and traction control (multi-step rev limiters, vss vs time or rpm, etc) within megasquirt, I can maximize acceleration without having to dedicate the rear suspension of the car strictly to drag racing geometry. It's amazing what you can do with modern technology. It will also let me run a flex fuel sensor and automatically configure my boost/fuel/timing maps to whatever ethanol content I happen to have in my tank.

Things I'm still researching/happy for any opinions on:

1. Turbo sizing (compressor/turbine wheel and a/r ratios)

Since this is mainly a street car, drivability will be key. I think I'd like to achieve max boost by 3500-3600 rpm's which is what my minimum rpm will be after my shift to 2nd and 3rd at WOT shifting at 6k. I'm going to be running a stock block entirely so I see no point in spinning the engine to death when the cam is really done by 6k anyhow. I'm not too concerned about part throttle boost as I'm sure the hemi will get me around more than fine and I assume the majority of that part throttle driving would occur from idle to 3k rpm's. That said, on the performance front, I'd like to run an 11.50-11.99 quarter mile reliably on street tires (not dot slicks/radials). Based on my math (this calculator, rwd/550 bhp/1588kg=3500lbs) that seems like it should take around 550hp +/-? This article I posted earlier makes me think the engine will put out around that much power with 8 +/- lbs of boost and do so safely/reliably on E-85 with gobs of timing. If/when it's necessary to run 91 octane I could just have the computer throttle back the boost/timing to acceptable levels. I'm not stuck on any hp number or boost lbs etc, I just want to accomplish my goal with the minimum amount of stress to the powertrain.

2. Intercooler sizing

I want to run an air/air intercooler for simplification and reliability as well as heat soak avoidance. Sizing can probably be around 22x16x? (HxWxD). Depth will be reliant upon room between the a/c condenser and the grill. I'm hopeful that 3" should fit, no idea as of yet though.

3. Pipe sizing

General sizing of hot side and cold pipe. The center dump headers I intend to run have 1.75" primaries with 2.5" collectors. I intended to run the 2.5" collectors together under the engine and then run a single 3.5" pipe up to the turbo. Since the turbo is the smallest constriction in this point, does it really matter what size the pipe is up to the turbo so long as it's no smaller than the diameter or the turbine inlet? As for the downpipe I think I can fit up to a 3.5" down past the engine on the passengers side rear where I intend to split it into 2.5" duals, contemplating a mid sump pan so I'd have the room under the oil pan before the transmission to do so. I'm trying to maximize ground clearance and will be modifying the torsion bar crossmember to run my exhaust through it. On the cold side I don't entirely know what size to run. Whatever the compressor outlet is? I don't know yet about what size the inlet/outlet will be on the intercooler but the throttle body on the hemi is 80mm or around 3.15". I also know there is a pressure drop across the intercooler due to temperature change and inefficiency. I'll have to compensate for this with slightly more boost at the turbo.

That's all I have for now... Thanks to anyone for weighing in!

-Ryan

 

[MoparPowa]

Here are some of the results of the squirrel performance turbo calculator I've posted links to. I've included the settings I used as well as the the outputs of the calculator for each data point it plots. The turbos are in the following order: T76, T80, T88, GT4508, GT4708.

 

[blown71duster]

These guys seem to have found what turbos work on the hemi engines.
They could point you in the right direction for a turbo for the power you are wanting to get and you could build the hot and cold side yourself .Getting those heavy jeep srt vehicles down in the 8-9 second 1/4 mile zone is impressive.

http://www.stage6motorsports.com/

 

[MoparPowa]

These guys seem to have found what turbos work on the hemi engines.
They could point you in the right direction for a turbo for the power you are wanting to get and you could build the hot and cold side yourself .Getting those heavy jeep srt vehicles down in the 8-9 second 1/4 mile zone is impressive.

http://www.stage6motorsports.com/

Sent them an email, thanks for the tip. It is definitely wild that they can push these tanks into the 8's. I'll probably send a few more emails out for sizing ideas to the big names. Once again, any all input is welcome.

-Ryan

 

[MoparPowa]

Here are some of the early a body intercooler options I've found online...

Additionally, the turbo sizing recommendations I've gotten back from some of the bigger names in the business.

Stage6motorsports - Precision PT6766 CEA, T4 .81 or .96

PWR - T4 67mm turbo, specifically the Borg Warner S300-66 ETT with a 1.0 a/r. PWR also recommended a 6.1 cam with aftermarket springs or 6.1 exh springs all around and forged pushrods.

Precision Turbo - PT7175 CEA with T4 .81 a/r for quicker spool or a .96 for slightly slower spool. They expected 2800-3200 rpm spool with the .81 a/r housing, the .96 would be 3-400 rpm slower.

Still waiting on answers from forcedinduction.com and Turbonetics.

 

[HOTMOPR]

Single borg warner S400 would probably be the cheapest and best route depending how much you plan on building the Hemi. If its a mild build that's what I would run. If you plan on building the hemi look at a S480..