Turbo sizing

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MoparPowa

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Looking to put a single turbo on a 5.7 hemi. Totally stock engine, contemplating a 6.1 cam/springs and possibly pushrods by recommendation of PWR racing and a few other things I read on forums (lxforums, etc). No idea on gains from this cam, just know it is recommended for forced induction purposes. No other modifications on the engine besides the later valve covers and coil packs. It will be run by an aftermarket ecm, megasquirt in all likely hood and I intend to run it with a flex fuel sensor to utilize E85. My goal is 11.50-11.99's in the quarter with a car built to turn on high performance street tires, not dot slicks. According to the majority of 1/4 mile calculators out there, one specifically being my favorite (link, requires weight in KG), it should take around 550 hp to pull this off. While the power will be easy, the launch will not, but I think it can be done. It has a fair amount of tire, 315/35/R17, with a RMS triangulated 4-link, but it's obviously not gonna hook like a drag car. Only 25.7" tall tire in the rear. I intend to combat this with aggressive boost control options offered by megasquirt (boost by gear/rpm/etc), launch control options (multi-staged rev limiters) and traction control options (vss, rpm, etc). I think the car can be made to have a reasonable, consistent launch. The 60' can be made up for down the track by the turbo. The transmission I'm running does have some relatively low rpm drops, 3600rpms or so coming into 2nd and 3rd but I think the 600+ ft.lbs of torque these engines seem to be putting out at that rpm range should pull through it just fine. I will either be running 2.76's or 2.93's, the first gear of the transmission is very steep at 3.753 requiring this. The accompanying benefit is a cruise rpm of 1800-2000 rpms @ 70 mph, hopefully lending to some outstanding mpg results. I expect the car to weigh in at no more than 3500lbs with me in it in full street trim. Mustang aluminum spare tire, full tank of gas, the whole deal.

I have another thread running here in the forced induction section but it seems like this would get some more useful input in this subforum. I'd highly recommend you look at it if you don't mind, it details a variety of different details about my plans. I'm really just looking for assistance on sizing the turbo, cold and hot side piping, and just general experience people have with this situation.

As always, thanks for any input.

-Ryan
 
Check with your local sanctioning body, ie NHRA, as to what you can use for rev limiters, rpm controllers etc before you invest tons of money just to find out you can't use it at the drag strip.
 
Check with your local sanctioning body, ie NHRA, as to what you can use for rev limiters, rpm controllers etc before you invest tons of money just to find out you can't use it at the drag strip.

Hi Dorian,

Thanks your for response. As to regulations, I'm really only interested in the capability to run that quickly. I don't necessarily have any intentions to compete or otherwise be subject to any such rules such as those outside of the safety regulations which is why of course I am sticking to 11.50 or slower. Like test and tune nights or whatever... I wouldn't honestly expect the car to be competitive on a strip, that's by no means what I'm building it for. Any competition I will be doing will be in SCCA parking lot autocross and that would be strictly for fun. This is really a driver first and foremost... That's why I want to go turbo, crazy power when you want it, otherwise it should drive like stock. I'd just like to have max boost coming into the minimum rpm of my next gear which means around 3600 rpm's. Seems more than doable to me with such low boost requirements, I can't imagine going past 10 lbs.
 
I can't remember the exact name of the article off the top of my head, but they did a junkyard budget turbo hemi build in one of the magazines. Took a junkyard engine and Ebay specials for turbo bits and made something like 600 hp for $3400 (including engine) or something like that. Should have a parts list for what they used to get there. The turbo system was one they actually built for an LS to start with, then adapted to a Ford, then to the Hemi to see how the big three stacked up. Can't say what kind of driveability or longevity it would have, but may give you a direction to look at.
 
I can't remember the exact name of the article off the top of my head, but they did a junkyard budget turbo hemi build in one of the magazines. Took a junkyard engine and Ebay specials for turbo bits and made something like 600 hp for $3400 (including engine) or soething like that. Should have a parts list for what they used to get there. The turbo system was one they actually built for an LS to start with, then adapted to a Ford, then to the Hemi to see how the big three stacked up. Can't say what kind of driveability or longevity it would have, but may give you a direction to look at.

Hi Map63Vette,

In my original post I linked to my other thread in the forced induction subforum. In that thread i actually linked to the build you're referring to. It was by Hotrod and unfortunately didn't offer many technical details outside of the power gains. It was impressively cheap however at under $4k. Thanks for your input.

-Ryan
 
Hi Map63Vette,

In my original post I linked to my other thread in the forced induction subforum. In that thread i actually linked to the build you're referring to. It was by Hotrod and unfortunately didn't offer many technical details outside of the power gains. It was impressively cheap however at under $4k. Thanks for your input.

-Ryan

Ah, gotcha. Did you try digging back through their articles to find the original LS and Ford builds? Might have some more component info in there. The Hemi one kind of seemed like an afterthought anyway. Granted the piping cost and such would probably be a little off since it wasn't built around fitting in a specific car.
 
Ah, gotcha. Did you try digging back through their articles to find the original LS and Ford builds? Might have some more component info in there. The Hemi one kind of seemed like an afterthought anyway. Granted the piping cost and such would probably be a little off since it wasn't built around fitting in a specific car.

Not a bad idea, I hadn't looked too hard. Since they used the same components I didn't think they'd have any more info specifically in regards to sizing the turbo. I'll look into it though, you never know.
 
I have zero experience with new gen hemi's and turbo's. I'm very interested in seeing what you find works.

Have you considered building a forged short block down the road? I would recommend it, in the event that you decide you want more power. I think your current power goals are attainable on a stock short block, but pushing much further will be in uncharted territory. Most LX guys keep it to 8 psi (or 10-12 psi if they're gambling men) on stock short blocks. Forged motors with head studs still lift heads somewhere at or after 20 psi, though.

What aftermarket K member are you planning on using?

Have you considered running the truck or jeep 5.7 log manifolds? Pointing them forward?
 
I have zero experience with new gen hemi's and turbo's. I'm very interested in seeing what you find works.

Have you considered building a forged short block down the road? I would recommend it, in the event that you decide you want more power. I think your current power goals are attainable on a stock short block, but pushing much further will be in uncharted territory. Most LX guys keep it to 8 psi (or 10-12 psi if they're gambling men) on stock short blocks. Forged motors with head studs still lift heads somewhere at or after 20 psi, though.

What aftermarket K member are you planning on using?

Have you considered running the truck or jeep 5.7 log manifolds? Pointing them forward?

Hi Uhcoog1,

Did you happen to look at my thread I linked to in the original post? I answered a few of these questions, manifolds, etc. I don't have any current intention to build a shortblock to up the boost. Due to the fact these power levels, 500-600 hp, will already be pushing the usable limit in a street car I don't really see any point in more. You can see the details of my build, k-frame/etc here. Thanks for your input.

-Ryan
 
Looks like fun Ryan.

Yes, I skimmed the other thread. Guess I missed some of where you addressed that.

You probably put this somewhere else as well- but have you considered a centri supercharger? Like a novi 1200 or 1500? I have a bracket in selling right now on LX forums.

You must be more mature than me- I always want more power. I want the most power I can use in 3rd gear on a road course while rolling into the throttle. If and when I get there, I'll probably then want the same in 4th! Such is the hot rodders natural progression.
 
What you're building has been done quite a few times by magazine builds and guys running modern mopars. If you can't find the info you need pm me and get you going in the right direction.

A single 76mm Ebay China turbo will reach those goals. Take it apart when you receive it and make sure you use the proper torque specs and thread lock.

You could spend more on a name brand turbo and not have those worries.

If you went twins you could run twin 57mm but I would go for the twin 61 route. You won't lose much spool time if any and your ceiling will be well beyond what you're describing.

I wouldn't push the stock motor passed 500rwhp. Most of the reading I've done suggest the pistons won't last very long above that power level. That will be in the 8-10lb of boost range.
 
I learned a thumb(?) rule(???) inducer(mm) x inducer(mm) / 6 = Max hp for compressor.
lets say a 76mm china turbo. 76x76/6 = 960HP.

if you going stock bottom end, I would put in a bigger camshaft in it with much overlap and tight LSA to get away with cylinder pressure. You do not get alot of power in the low rpms, but much more fun i the top, and its easier for the engine! its the cylinder pressure that destroy the engine!

I believe there is no such thing as a "turbo" camshaft. you may turbo any camshaft! at 14psi, your power output is aprox doubled over NA power. build yourself a nice crisp 400hp engine and turbo it.7psi - 600hp 14psi - 800hp...

good luck! :)
 
Looks like fun Ryan.

Yes, I skimmed the other thread. Guess I missed some of where you addressed that.

You probably put this somewhere else as well- but have you considered a centri supercharger? Like a novi 1200 or 1500? I have a bracket in selling right now on LX forums.

You must be more mature than me- I always want more power. I want the most power I can use in 3rd gear on a road course while rolling into the throttle. If and when I get there, I'll probably then want the same in 4th! Such is the hot rodders natural progression.

I believe I addressed that suggestion with jw97 in the other thread when he made the same suggestion...
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.

It simply centers around running a single turbo and the necessary pipe routing. I don't really want to run twins or see it as necessary for my hp or spool requirements. As to the desire for more, I don't know about maturity, truth be told this will be the fastest car I've ever driven, much less ridden in. I may eventually end up thinking I want more but I already have a plan for that. Contemplating another build down the road with another early a using a 904 or 727 auto behind a 2.4L turbo. Could do it properly then with a cage, etc. A real race car that could actually make use of that power and would still be unique doing so. However, that's a trip to the moon away. Just want to get this thing running! :burnout: In regards to a centrifugal supercharger, call me silly but I just don't like the concept of a belt driven turbo. I'm not against superchargers by any means, I'd love to run a twin screw or a roots tvs style blower on the hemi, but I simply can't afford to spend 6k for something like that. I'm already putting too much into this car as is. I feel more than confident this turbo can be done very nicely for significantly less than that.

What you're building has been done quite a few times by magazine builds and guys running modern mopars. If you can't find the info you need pm me and get you going in the right direction.

A single 76mm Ebay China turbo will reach those goals. Take it apart when you receive it and make sure you use the proper torque specs and thread lock.

You could spend more on a name brand turbo and not have those worries.

If you went twins you could run twin 57mm but I would go for the twin 61 route. You won't lose much spool time if any and your ceiling will be well beyond what you're describing.

I wouldn't push the stock motor passed 500rwhp. Most of the reading I've done suggest the pistons won't last very long above that power level. That will be in the 8-10lb of boost range.

Hi MattP,

I know... The magazines just kill me because they rarely address issues of interest to people who aren't strictly looking for max hp/torque in their weekend bracket racer. Like spool time, tuning, sizing, intercooler performance, lessons learned, the list goes on and on. That said, I have learned quite a bit from this article (linked in my other thread as I already mentioned), but that was mostly in what power levels to expect, etc. It did turn me on to Ebay intercoolers from cxracing which I am currently researching sun up to sun down. I'm really excited about where it looks like this build is going and I don't see any clear complications, just really looking for anyone's experience in sizing a turbo on these engines. Thanks for weighing in.

I learned a thumb(?) rule(???) inducer(mm) x inducer(mm) / 6 = Max hp for compressor.
lets say a 76mm china turbo. 76x76/6 = 960HP.

if you going stock bottom end, I would put in a bigger camshaft in it with much overlap and tight LSA to get away with cylinder pressure. You do not get alot of power in the low rpms, but much more fun i the top, and its easier for the engine! its the cylinder pressure that destroy the engine!

I believe there is no such thing as a "turbo" camshaft. you may turbo any camshaft! at 14psi, your power output is aprox doubled over NA power. build yourself a nice crisp 400hp engine and turbo it.7psi - 600hp 14psi - 800hp...

good luck! :)

That's an interesting rule of thumb I've yet to come across. I'll have to look into that. As for cylinder pressures, I expect they'll be high and I'm hopeful to run quite a bit of timing to encourage some low rpm torque for normal driving outside of boost. I suspect E85 will assist in meeting those requirements with relative ease.

So far, I've been recommended by:

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.

Inertia Motorsports - Really only weighed in to tell me that they'd recommend a stock computer or I'd just blow it up, really disappointed in that answer to be honest. Sounds more like friendly marketing than an honest answer. Numerous hemi's run on aftermarket ecm's? Maybe just a lack of experience with them...

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.

I will say that I'm not in the market for an expensive ball bearing flux capacitor turbo... The precision recommendations are definitely higher on the money tree, the borg warner extended tip tech seems interesting with the wider maps and they are lower priced from what I'm finding. 66-71mm is the current inducer range recommended, we'll see what forcedinductions.com responds with as well as turbonetics, I shudder to even think what they'll recommend price-wise.

-Ryan
 
Ryan-

I'm very interested in your build, and I actually don't want to sway you away from the turbo (because I want to see what you can do with it).

FYI- the centri set-up's can be a lot cheaper than you think. Take this one for example:
[ame="http://www.ebay.com/itm/Dodge-Ram-Hemi-GS-Motorsports-Supercharger-kit/191154506398?_trksid=p2050601.c100085.m2372&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20140211132617%26meid%3D6695064064154451990%26pid%3D100085%26prg%3D20140211132617%26rk%3D3%26rkt%3D4%26sd%3D291138520242%26clkid%3D6695065258991655181&_qi=RTM1562571"]http://www.ebay.com/itm/Dodge-Ram-Hemi-GS-Motorsports-Supercharger-kit/191154506398?_trksid=p2050601.c100085.m2372&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20140211132617%26meid%3D6695064064154451990%26pid%3D100085%26prg%3D20140211132617%26rk%3D3%26rkt%3D4%26sd%3D291138520242%26clkid%3D6695065258991655181&_qi=RTM1562571[/ame]

That's probably a novi 1200, which is more than adequate for what you're after. Bolt on to what you have, front cover and all.

Disclaimer: that's not my ad, I don't know the guy, and I caution against buying used centri's and turbo's. My buddy bought one that had a chipped compressor wheel - turned out to be a bad deal. Just look things over closely and budget a rebuild kit when you buy.
 
Open up the ring gaps like +.008 top ring and +.012 2nd ring IIRC is the secret sauce for turbo low buck stuff. The Hemis have a shallow top ring land as apposed to the ls shivvys much deeper top land. That really is their only advantage. Smart money is either using a high mileage engine, +100k, or open the gaps or both.
 
Ryan-

I'm very interested in your build, and I actually don't want to sway you away from the turbo (because I want to see what you can do with it).

FYI- the centri set-up's can be a lot cheaper than you think. Take this one for example:
http://www.ebay.com/itm/Dodge-Ram-Hemi-GS-Motorsports-Supercharger-kit/191154506398?_trksid=p2050601.c100085.m2372&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20140211132617%26meid%3D6695064064154451990%26pid%3D100085%26prg%3D20140211132617%26rk%3D3%26rkt%3D4%26sd%3D291138520242%26clkid%3D6695065258991655181&_qi=RTM1562571

That's probably a novi 1200, which is more than adequate for what you're after. Bolt on to what you have, front cover and all.

Disclaimer: that's not my ad, I don't know the guy, and I caution against buying used centri's and turbo's. My buddy bought one that had a chipped compressor wheel - turned out to be a bad deal. Just look things over closely and budget a rebuild kit when you buy.

No disagreements there, centrifugal superchargers can be very cheap. As I mentioned originally however, I just don't see the point of a belt driven turbo. I'd either have positive displacement or turbo. Not to mention that kit originates from GSM and I don't think I'd touch anything they made with a 10 foot stick based on every single piece of feedback I've found. I do understand where you're coming from though and I appreciate the interest. I will admit this is a slow going project but keep poking at me and I'll be sure to keep poking at the car.

Open up the ring gaps like +.008 top ring and +.012 2nd ring IIRC is the secret sauce for turbo low buck stuff. The Hemis have a shallow top ring land as apposed to the ls shivvys much deeper top land. That really is their only advantage. Smart money is either using a high mileage engine, +100k, or open the gaps or both.

My engine was a rebuilt core (sort've? I don't entirely know the history) that was reassembled by an individual that works or worked for PWR and I got it with everything included for $1200 shipped. Felt like I did pretty good there. From what I was told it is an 05 charger engine with around 55k miles on it. In regards to ring gaps, I assume you mean to allow for thermal expansion. As I plan to run E85 at the same power levels people are running without meth even I feel more than confident the EGT's will be comfortably within spec and likely lower than high compression N/A builds. On standard pump fuel boost will be reigned back to a very conservative limit and the car would unlikely be driven full throttle without alcohol in the tank. I will be intercooled as well of course. Speaking of which, I'm gonna throw some pictures up on the other thread of various intercooled early a-bodies I've been finding in my recent research. Assessing my options...
 
GSM kits were a problem due to tuning. The bracket and head unit are quality.
 
GSM kits were a problem due to tuning. The bracket and head unit are quality.

That rings true based on what I've read, however, like in many things, you have to wonder what else was half-assed if they didn't have one of the most important things right. Luckily for me, they don't really fall in my line of interest anyhow. Your website you never update by the way, you should update it. I used it for the VE maps to base my turbo calculations on, don't think people aren't going there or finding it. Thanks for posting it in the first place.
 
Glad you found it useful. That site needs a huge makeover. Maybe one day.
 
The gsm LX bracket is the preferred bracket over the vortech bracket, btw. I don't know about the truck bracket.

The hemi's were nearly impossible to tune when the gsm kits were out.
 
I can't remember the exact name of the article off the top of my head, but they did a junkyard budget turbo hemi build in one of the magazines. Took a junkyard engine and Ebay specials for turbo bits and made something like 600 hp for $3400 (including engine) or something like that. Should have a parts list for what they used to get there. The turbo system was one they actually built for an LS to start with, then adapted to a Ford, then to the Hemi to see how the big three stacked up. Can't say what kind of driveability or longevity it would have, but may give you a direction to look at.

it was car craft, i have the article at home. i just picked up a 5.7 with a bent rod and im thinking about running the same set up on my dart.
 
if you guys wanna see some of the cheap cxracing turbos kicking *** look up denmah on you tube, the guy takes junk yard ls engines bolts the cheapest parts he can find on em and goes, right now he has a cx turbo 20llbs of boost mismatched heads and is running low 9's on street tires
 
Run a 67/66 turbo. Listen to the guys at stage 6. More 1000+ horsepower turbo cars come out of there than anywhere in the gen3 world. Get some mild work done on the heads. Especially the exhaust side. I can spec a cam for you. Should be easy enough to make 450 - 550 wheel on a stock bottom end at 7-8 PSI. A 6.1 would do better than a 5.7. They heads are the big difference. A little more compression.....we run 7.5 PSI on the 6.1 and make about 600 wheel.
 
im gonna be folling this thread, i just bought 2 5.7 hemis yesterday and ordered a t76 borgewarner turbo wuth the t6 flange this morning.. im planning on using fast efi, and str8 headers i bought to get the thing started
 
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