Get dustd

Hello LS1 tech, gotten a lot of good info but have not posted yet.

So long story short I built a forged 6.0 with lsa heads and a nice t56 magnum and put it in a e39 M5. I have a s400 80/87 and a pro efi to run it on e85. I was hoping to make some strong power numbers and still have it streetable with AC. I am laying it all out and fabricating up the hot side and working out the cooling system right now. The car just is not as big as I thought it was... I am afraid I am going to get this all together and it is going to run hot or the exhaust is going to melt my headlights or just be too restrictive. I could have done the low mount with the turbo with a pump but I would still have had to run the short radiator and plumbing would not be easy either. The other option would have been ditching all this and doing twins but I am sure that would be tough too. The compressor was just too big to fit behind the headlights. Another guy did it but had to run electric power steering and I did not want to do that. It was a pain to figure out the accessories and get this far so I committed and boxed out the frame rail and made my mount last week. I found another thread with a guy (actually building another turbo bmw on here) that was asking about running a small but thick radiator and people seemed to think it was fine but there was no confirmation on if it worked or not.

To sum it up my hot side is on the DS frame rail facing the fender and the downpipe takes a quick down turn and loops under the frame rail. The compressor is so big I cant sneak a radiator behind it like I thought I could. I found a nice thick sprint car radiator by FSR and had them make it into a dual pass so with right side in and outlets. I will make a the taurus fan work fine vertically with it after some trimming and fab work. Not much room at all for a 5" intake and to me a filter is a must so that is another thing... The downpipe is a half inch from a headlight connector and I wanted to run it to the driverside but I do not think I can make the turn with that big 4" pipe. So my concerns are: Is this cooling system going to work on the street with AC and no pusher fan? Is that downpipe wrapped with the connector insulated be safe? Is that long of a downpipe run ridiculous? I feel like there is going to be 25 feet of exhaust if I go pass side. My plan is to run 4" all the way back to the dual 3" inlet dinan straight through mufflers. Here are some pics and thanks for any input.

-Joe

twinturbo496

iTrader: (2)

Do you need the trunk?

Get dustd

Yea. I am keeping the rest of the car bone stock.

Forcefed86

iTrader: (4)

What are the exact dimension of the radiator core you have? Approximate max vehicle weight with driver? Use the attached sheet below to calculate radiator core area needed. It’s never left me overheating…

Was able to sneak by with a 14x14x3.5” core on my 370 with a 4” thick IC blocking it 100%. (taurus fan on high) Would most likely overheat with AC though. Taurus fan is a good start. Make sure the shroud covers the core 100% and is sealed around the edges even. Can make a few flaps on it if you are concerned about flow through during highway speeds. I’ve never had an issue with my setup on the highway with no flaps.

What are your power goals? Are you sure you need 4” exhaust? Is that an 87mm major or minor diameter on the turbo exhaust wheel?

I’d want some sort of ceramic coat on the hotside that’s ½” from the headlight, then wrap it. And most importantly use a steel shield of some sort with an air gap between the down pipe. If there is airflow around that area (from the fan or otherwise) It might be ok. I’d seriously think of necking down to 3.5 or even 3” pipe depending on your power goals. You can also put that area of pipe in press and flatten/oval that area. You won’t lose much flow. I’d want a good 1” even with the wrapping and heat shield.

Also it looks like your hot-side piping is pretty large? What size is that? Would dropping the piping down to 2”-2.25” to the flange free up any space?

Think the trunk comment was suggesting you place a radiator in the trunk. That would work fine. Use a remove electric pump, huge radiator and nice fans in the trunk area and it will be fine. It’s a lot of work though.

You can also run multiple smaller core radiators. I’d run an aftermarket high flow water pump as the more radiators you add (esp inline. Try to run parallel) the harder the pump has to work.

Have you seen the cobra head couplers? You can get 6” ones these days reasonably. Then neck down one side to fit your turbo inlet with inserts. Not super cheap but if you’re in a bind nothing will give you more clearance in a tight 90.

http://www.intakehoses.com/mm5/merch...gory_Code=CHEW

Also take a look a the R2C “BLACK HEX” air filters. They flow like 5-6x what a K&N does per SQ inch of media. So you can get by with a smaller filter.

http://www.ebay.com/itm/S400-Turboch...-/322336884306

5” alum dryer ducting also great for tight bends. Fiberglass it afterwards and its plenty strong… air tight, water proof, and light weight. Pic angles are a little off but this is really a pretty complex bend that stays 5” ID all the way through.

Get dustd

These are all great ideas about the intake. I can also cut a big notch out of the fan housing too. There are like two inches before it gets to the blade so I can make some room there as long as the fan is still supported. Thanks for the reply and all the help with this. Let me know what you think about that core size. I will try to do it just off my basic core size. I think I am over thinking that.

Forcefed86

iTrader: (4)

E85 isn’t going to help a noticeable amount with coolant temps in my experience. Farting around with idle timing can help a bit. I idled cooler at 26* than I did at 17* I ran initially… but not my much.

It’s just basic area LxWxH of the core only. So you have 836” worth of core.

Start with 2 and add or subtract the numbers listed based on your application. I guessed and got 2.3 for yours. So 2.3 X 366 cubes = 841” of core to cool properly. So a little shy maybe, but probably ok with that monster fan. Don’t forget to use large wiring to go along with it. It pulls up to 60a initially on high and will fry a standard 40a relay pretty quick. I use the 90a golf cart solenoids. Pretty cheap on ebay think I gave $13. I use a standard 40a relay for the low setting and they seem to hold up fine. Adding pushers to the Taurus puller didn’t do diddly when I tried it.

600-900+hp is a pretty big swing. 120% larger than the exducer on the exhaust wheel is a pretty good rule. See if you can measure the ID of the exh housing exit. So if you really have an 87mm exducer you should run 4”.

My 370 is around 1000 CHP and I’m using divided 2” hot-side piping on factory manifolds. I think you could step down to 2”. But .25” probably isn’t worth the clearance/effort.

Get dustd

Yea I will stick with the 2.25" x over, I don't think that will help me much. And it is 87mm so I think I am going to stick with the 4" downpipe and just dent it and move it as far away as I can. As for the radiator I went through the list and got 2.1 and I am really thinking the dual pass is worth quite a bit. Not to mention it is a really well put together radiator. Worst case I will make a tubular core support and cut it out and move a thinner radiator back and only have a fan on half of it.

The last question would be is another say 3 or 4 feet of exhaust tubing a big deal? The run to the pass side would be a bit easier aside from getting around the starter. If not I can get some tight radius bends and make the drivers side work.

Forcefed86

iTrader: (4)

I'd try to keep it as short as possible. Mild steel 4" donuts are about $45 on ebay. Probably the same cost as 4 ft of 4" tubing.

Good luck! Looks great so far.

gtfoxy

Nice build. Love the idea.

I have been contemplating this type of set-up as well.

For the inlets to the turbine you can taper-cut them & weld them so they are ~2", if you want to go through the trouble. I did it for mine.

Get dustd

Thanks guys, Looking at those air cleaners...I may just be able to notch the fan and pop one of those on. I know cool air is worth a bit on an N/A engine but is it as valuable on a turbo engine considering it is going to be heated up immediately anyways?

I will do whatever it takes to run down the drivers side. I totally forgot about those donuts. This is why we internet.

Forcefed86

iTrader: (4)

Def don't want hot air at the inlet. But you can box/duct it later on. With an effecient IC LJMS said something along the lines of each degree you drop at the inlet is worth like 3-5 off your charge temps post IC. So it makes a pretty big difference.

ScottyBG

I think that 1 degree off inlet temp to 3-5 degrees post IC is total bull $hit. That's an old wives tale by someone who clearly doesn't have any understanding of thermodynamics. I would probably never buy from someone that was that knew that little about turbocharging to believe that.

Sorry for the lesson in thermodynamics., but here goes.

Air follows the universal gas equation, PV=NrT. Temperature rise due to compression in the turbo is proportional to the amount of compression regardless of the incoming temperature. So basically doubling the pressure doubles the temperature coming out of the turbo. The higher the compression, the more this multiplier. In the case of 15psi, we would be doubling the pressure over atmospheric, and the temperature of the incoming air. So their is a multiplier effect coming out of the turbo, however this is more than made up for by the intercooler.

Moving on to the intercooler, 1 degree of inlet air should equate far less than 1 degree temp post intercooler. Warmer air entering the intercooler makes it more efficient, meaning it can transfer more heat from the charge air to the ambient air. For example if you have 120F air entering your intercooler and its 100F outside you only have 20F temp difference to drive heat across the intercooler. If you have 160F air going into the intercooler and its 100F out side, you have 60F temperature difference and the intercooler is going to drive more heat across it out of the charge air, back into the ambient air.

As an example if you have an intercooler that is 75% efficient it can take 120F intake air down to 105F post intercooler with ambient air of 100F. For reference 100% efficiency would drop the charge air all the way to 100F or get the full 20 difference. In the case of 160 F entering that same 75% efficient intercooler would drop the air temp to 115F, 75% of the temperature differential. So in this case 40 degrees of intake air only equates to 10 degree difference post intercooler. Someone probably got their ratios backwards in the discussion of this story at some point in time.

Don't get me wrong lower air temps are always better, but that idea of it multiplying doesn't hold with the laws of thermodynamics. That heat rise doesn't hurt you as much as you think it does.

For those of you still in doubt, consider this. If this 3-5 degree difference we true, lets take for the sake of argument 4 degrees, the mid point. If on a 50 degree day our turbo cars had an air temp of 80F at the throttle body, a reasonable number with turbo operating in the proper range on its compressor map, and a decent intercooler. Then on a summer day of 100F, we took this 50 degree temperature difference, and multiplied it by the 4 we would have a 200F increase in post inter cooler air or 280F at the throttle body. We couldn't even drive our cars on warm days if this were true. We could expect to see more like 130F on a 100 day with that same turbo and decent intercooler. It is more like a 1 to 1 ratio.

Just needed to debunk a myth, and not have people chasing something that isn't nearly as beneficial as they may think it is. As said earlier cooler is still better, but not the holy grail, we can still run fast on hot days too!!

Forcefed86

iTrader: (4)

I don’t mind at all, I’ve never tested anything like that. Personally I can’t see ever plumbing a setup that sucked hot air to start with.

But I wouldn’t jump all over Lil ‘Johns statements as BS without all the facts. My fault there. He was talking about an Iced A2W setup specifically in that statement. I shouldn’t have used it. I don’t believe he was pulling info out of thin air, sounded like actual experience to me. Iced A2W IC’s can be more than 100% efficient.

ScottyBG

I guess what I was trying to convey, when something is repeated many times by many people, things are lost in translation. It is the old story growing as it is retold. Nothing against you or LJMS, I'm assuming it was probably just some guy, no particular individual. If you were to say on a hot air car running high levels of boost, that 1 degree of intake temp equates to 3-5 at the throttle body, the calculations would show that to be pretty darn close to correct. That would be due to the fact that there is no intercooler that gets more efficient at higher temperatures, to off set the turbo which becomes less efficient at higher temperatures. In the case of our intercooled cars there is a balance that brings charge temperature back into reasonable numbers.

Get dustd

I do not know for a fact but I was just assuming the turbo generates so much heat at can't make that much of a difference. It will be months from now but I will try to remember to try both ways and compare intake temps on the same day. It's fun to get numbers like that. On another note Sound Performance makes a sweet boost activated cutout using a wastegate actuator...I think I am going to run the exhaust to the passenger side. It will just help soo many things. The trans front cluster spray pump location, oil feed for turbo and maybe some day oil cooler lines, engine mount, power steering lines, and the list goes on. It is worth the extra 24" of tubing to me, If i pick up decent power with the exhaust disconnected I will run a cutout.

Another interesting discussion topic:
I wonder how bare ceramic coating compares to wrap. It's hard to believe it could do anywhere near as much as wrap. On my last turbo car I could make a pass after driving an hour and hover my hand directly above the down pipe. On the other hand, there NASA does not use ebay header wrap on the space shuttles, they use ceramic tiles...I think.

Get dustd

Just because I hate when you read up on something like this with no conclusion...So far so good. I ran the car for over an hour with no airflow. Even indoors at 70 degree temps I can let it climb to 210 degrees and kick on the dorman Taurus fan and it will drop it down to thermostat temp no problem. Car is not tuned yet so it has not seen thrashing but the early results leave me hopeful. Some sprint car guys make the radiator and if you call them they will set it up as a dual pass for LS cars. I think it was around $400. I will only post again if I have issues. If I do not assume this worked well in the summer heat, with ac, and getting beat on.

http://www.speedwaymotors.com/FSR-62...9eCBoCYHDw_wcB

scottywheels

I ran my radiator int he back of the car and now I run a 12x12 that lays flat but I do not street drive my car very car lol

roastin240

iTrader: (13)

I have been arguing this with people for years! Usually loose whoever I am talking to once I say "ideal gas law"...I am typically interrupted with ooohh you F'in engineers and your calculations...blah blah blah. Lmao, pretty sure I learned basic thermo when I wasn't even a legal adult.

Ratical

iTrader: (82)

I run a JEGS Performance Products 51965 Scirocco/Pro Stock Style Radiator 2 Row 1" Core.
Overall: 21-1/2" W x 12-3/4" H (25-1/2" Tab to Tab) Core: 17-7/8" W x 12" H

Costs $250.

I drive the car all over and Made 7 passes at the track in one day with no issues.

http://www.jegs.com/i/JEGS-Performan...51965/10002/-1

AND I have a large Treadstone intercooler in front of the radiator as well.

truckdoug

iTrader: (25)

i have used that scirocco radiator before. works great!