bumblebeerx8

iTrader: (7)

yeah I went on a long get-a-way. Did a lot of hunting and put the car stuff on the back burner. There has been a bit of stuff I missed. only some of interest though sadly. Got to get a new alternator and the weather to warm up then I will be back at it.

Harlan

iTrader: (3)

Only my latest welds are worth a darn, everything before that was hit or miss. Some of them I have had to reweld several times to get them to hold. And yes I am taking it to buddy at an exhaust shop to fix my mistakes. I've already changed my plans several time as things fell into place and I didn't like them. Part of the reason I went so cheap in this build is because I expected to have to change things on the way. My original coil mod is out the window, that cost me, converting to IGN-1A coils cost even more. I could have stuck with what I had, but I didn't like the reliability. Was going to regear the rear, but aside from being a dumbass I now like the s2 transmission better. Changes will continue until I'm done. Then it will be time to take what I've learned and get the plumbing done right, probably with a better turbo. I still have cash set aside in case I need to just trash the whole idea and replace my exhaust.

So if you have suggestions, I'll take em, otherwise sit back and enjoy the show.

Drove a little today. A little louder than I prefer, but should be fine when the turbo is spinning.

bumblebeerx8

iTrader: (7)

only thing I can say is really think about what your doing it may be cheap but when you buy 2-3 time its the same. Ive always said and stand behind fast,reliable,cheap pick 2.

You really need to think about how gases flow, material and what some of it will do to help and what can hurt. what you need temps to do and where and why I choose some of the parts I did. There are things that are different but it all can be solved for the most part.

I even stand behind that STS really hurt what a rear mount could be because of the things they did to make it user friendly for a average person.

If you can't come up with simple answers to some of these questions than any turbo build will be less that par even more so when you add extra variables

bumblebeerx8

iTrader: (7)

another thing that has me scratching my head is preturbo W/M injection, MAF sensor and BOV recirculated. It really doesnt add up unless your running back and fourth up and down the car.

olddragger

iTrader: (3)

aggg--you are right --not wastegate--but the bov. you answered my question.
I am curious as to how your maf/iat is going to react.

Harlan

iTrader: (3)

Air filter, then MAF , then the recirc taps in, then WI right before the turbo. Everything is going to be at the back of the car until the throttle. I'll have to run a post throttle reference line for the BOV from the front, but that's the only complication. We can debate the pros/cons of mild steel exhaust tubing or why I chose the charge pipe size I did, but it's what I picked and most of it's for a reason. I don't expect to throw everything together and have it be completely reliable, I don't even expect to be finished when everything is on and working. I've learned incredible amounts so far, developed new skills, and had a good time. For me that's what it's about.

Oh, OD. Hopefully my location for the recirc will work without too much blowback and the MAF won't see a thing. IAT is going to be right before the throttle body, so it shouldn't care either. Yes, I'm splitting the MAF and IAT. MAFs can't handle water and IAT is useless before the turbo.

bumblebeerx8

iTrader: (7)

sounds like you got it all figured out, good luck

Harlan

iTrader: (3)

I'm not even close to having it figured out. I've made a few bad choices already and payed for it. I have a reason (maybe not the right reason) for just about everything I've picked for this build, some of which will bite me in the butt. Please tell me any solid information you are willing to share.

BTW bumblebee why did you choose your exhast size? 3" is a little big even for NA, but on a turbo it's gigantic did you figure out the exhaust velocity through the pipe or just wing it?

Not trying to bust your chops, I love the quality of the build and am jealous of your skills, but I find the size a bit curious.

Edit: Here is what I used for sizing my charge pipe.
http://www.engineeringtoolbox.com/pr...pes-d_852.html You can get an idea on how much the pressure drop is with the exhaust by using EGT to estimate density and finding volume with that.

olddragger

iTrader: (3)

Oh--OK got ya concerning your routing. Turbo system are a little more complex for me to understand-lol
3 inch exhaust is needed because we have no overlap and it is all about providing the least amount of restriction. You want the least backpressure as possible to help with keeping the side seals as cool as you can.

From the Pettit site: We routinely receive Renesis engines that failed: some of the causes are listed below by order of popularity:

# 1 Turbo charged w/high backpressure ratio.

#2 Poor maintenance

#3 Overheated

#4 Hi mileage/excessive seal wear; regular use of Protek-R will greatly reduce the likelihood of this occurring.

#5 Bearing failure, the oil recommendation 5/20 seems to be inadequate, most Renesis engines opened have excessive bearing wear, we therefore recommend a quality 10/40 or 20/50 oil the latter for racing and spirited driving.

Hope this helps a little.

Harlan

iTrader: (3)

My point is, why not run a 4" exhaust or a 6"? With an NA or a supercharged engine the best options are either a tuned exhaust for scavenging (absolute best), or a properly sized exhaust to reduce back pressure. Going bigger also makes the exhaust louder because it increase the differential pressure across the exhaust ports and because of the exhaust velocity that causes. Mufflers smooth out the pulses at the expense of back pressure, which also slows the gas passing through the exhaust port. It's a balance.

But that's for NA/superchargers, turbos change the game entirely. Now you have an intentional restriction in the line, the turbo itself, which causes higher pressure between the engine and the turbo. Just imagine having a 3" exhaust all the way to the back and ending it with a 2" tailpipe, does that 3" pipe really drop back pressure significantly more than 2 1/2"? (the real question is how long is the 3" pipe and how long is the 2" pipe)

Post turbo backpressure is your worst enemy. Differential pressure drives the turbo, so the bigger the pipe after the turbo the better (within reason). Best option is having the turbo exhaust go straight out the back of the car, and that's what a lot of remote mounts do. I couldn't get my turbo to fit where I wanted it without major modification so I compromised.

I didn't use the stock muffler as a housing because it was the best choice for performance, I used it because it was the best choice for getting everything together the quickest/cheapest. It won't spool as fast because of this, but it will be a proof of concept.

I eventually want to run stainless exhaust (for heat retention and durability) and an aluminum charge pipe (for heat transfer), it's too expensive though for something I'm going to change several times to get right. There are things I haven't thought of or haven't run across yet everywhere in this build. Will I end up with a puddle of water at the front of the charge pipe where it turns up to get to the engine? Will it even be a problem if I do? I have no clue! What will I do to counter this? Will a drain line going post throttle body work? That's only one of the one's Ive thought of and there are countless I've missed.

When I know exactly what I want I'll have someone weld it up for me. I walked into this with a lot of ideas, and of course putting them into reality has taken compromises some of which will be avoidable the second time through. Look at this build as a prototype for what I actually want to do, not as the finished product. If I was to do everything with the "right materials" the "right" way and an ever changing plan this would be a $20k+ build. Learn from my mistakes, learn from my success.

But please if you are going to call me an idiot, or question why I'm doing things bring facts to the table. I like facts and figures not opinions and hearsay. Sorry if that makes me sound like an ***, but I've had enough BS for now. If I'm wrong call me out and prove it, I don't mind. Tell me what you think instead of cryptic "being inventive only goes so far without looking at the basics. " or "lack of some fundamental research (pre-turbo water injection etc)" or "NYET ! on the air filter setup PM Bumblebbee why that is a badski idea ..................... " Statment's like that contain no facts add nothing, and only make me thing you guys are beyond your depth and talking out of your butts. Why do you think I ignore so much of the criticism? I share what I know freely, it ain't much, I share what I think freely and provide facts to back it up which can be debated if you like. I started this thread to share what I learn along the way, and to get suggestions from others. Right now I don't feel like sharing much, and about the only thing helpful I've gotten from this thread is my mistake on differential gearing (thanks for that BTW). So I'll go back to posting pictures and short little blurbs when I get things done, and you guys can continue to be negative without helping at all. I hope that some of what I find will be useful for others builds in the future.

TeamRX8

iTrader: (25)

you have a lot of inaccurate theories

Harlan

iTrader: (3)

Again a statement with no facts, no data, and no direction. If you think I'm wrong, show me how, otherwise why say anything?

TeamRX8

iTrader: (25)

because it takes up too much time, plus your posts make my head hurt with wtf spasms

Harlan

iTrader: (3)

I'll make my biggest point really simple, just for you Team. Use this Compressed Air Pipe Lines - Online Pressure Drop Calculator
Use the attached calculator with the following numbers:
500 cfm (at atmospheric conditions)
10ft
2" diameter
15psi
You'll get a 1.24psi drop. (or about 2.5"vac WOT at ATM)
Now try
500cfm
10ft
2" diameter
30psi (1 atm of boost)
You get a .62 psi drop. The resistance changed because the density changed, but the actual mass of air remained the same. Exhaust works the same way. Air is air. The difference is the density is lower because the temp is higher.


BTW Major changes to the build in the works.

olddragger

iTrader: (3)

absoulutly--exhaust for a street rx8 is indeed a balance! I learned a lot during my little journey with this cars exhaust and I still have a lot to learn. You are spot on about the post turbo exhaust system.
I think I understand what you are saying about using a 3 inch exhaust supply side to the turbo. I guess this will depend on how much air will be needing to find a way out?
Now with my old system
1- oem header, mazsport mid pipe, racing beat catback--i did a crude measurement ( per vacuum gauge/nipple on midpipe) and saw 4-5 inches of vacuum ( i live in middle ga) at wot.
2- After I installed a tube header with a 3 inch merge collector, custom 3 inch midpipe and modified the RB cat back connection point to 3 inches--i see only 2-3 inches of vaccum.
BUT--if i had a turbo at the end of both those system would I have seen the same result?
I don't think so--but I dont know for sure.
I THINK the most critical thing that would have a big affect on the backpressure between turbo and engine is to use the proper size turbo? A remote system down pipe design should not be as restrictive--should it?

Harlan

iTrader: (3)

I took my car into the exhaust shop to get a couple welds touched up. Was told point blank that although my welds would hold and it could be touched up and finished it would last about a week on the roads around here because of how low it hung. So, I bit the bullet and had it all redone.

Everything is tucked up in where the original exhaust was routed. I took this chance to go back to the drawing board and go to a previous design. The WG and turbo have individual mufflers and the turbo is 2.5 in and 2.5 out. Only a small part of the charge pipe hangs down further than the stock exhaust, and that was to allow it to cross over. I still need to drop the exhaust and wrap it to prevent it from heating up the charge pipe and I need to finish the oiling system for the turbo so I can remove the block plate, but this has taken a big load off of me. I don't have the charge pipe routed to the throttle body yet, but I have all the pieces for it.

Not exactly what I wanted, but much better than I had.

Harlan

iTrader: (3)

Here's what I got done today:
Pulled the exhaust and painted it with shaker can exhaust enamel.
Wrapped it to keep the heat in and the charge pipe cool.
Then wrapped it with aluminum HVAC tape.

I don't know if the aluminum tape will hold up, but I did find a couple other people who tried it successfully and say it does. After I got done I started the car and let the exhaust warm up. At idle I could still touch the exhaust pipe (although not for long since it was steaming!) and the charge pipe was cool to the touch over the entire length. The wrap should be much better at insulating after it dries out. (Have you ever touched something hot with a wet glove?!) I'm pretty happy with the results so far.

Still have a lot of work to do, but everything left can be done on the weekends while leaving me a car to drive to work.

dannobre

iTrader: (3)

The alum tape will be Ok... the adhesive is a different story It will burn off.. and then the tape will fall off. Hopefully it doesn't cstch on fire

Harlan

iTrader: (3)

The only thing that could burn is the adhesive. It's not the aluminized paper tape. Yeah it may just cook off all the adhesive and hang there. If so I will have to find something else, or get a real aluminized exhaust blanket.

dannobre

iTrader: (3)

I tried it on the rearmost muffler on my 85 GSL....lasted about 5 minutes till it got hot enough to melt the glue...and then it started smoking...then the aluminum tape started to come off
Wasn't pretty

Harlan

iTrader: (3)

Did you wrap the exhaust first? I wouldn't try it straight on the exhaust, that's way too hot.

olddragger

iTrader: (3)

it will not last. At the very least--over a little time it will get brittle and start to fail.
Even the aluminum part of the heating blankets ( from dei etc) will do the same thing, but it will remain intact.
I ended up making a thin aluminium heat shield that I installed in the direction it was needed. Home made heat shield if you will.

Previously when I wrapped mine ( under the car) it lasted only one year. With my lastest exhaust I uses the type wrap made with lava rock. People that have used it before told me that it does last longer. We shall see. I do not have my header wrapped.

Harlan

iTrader: (3)

We'll see how long it lasts. With a previous project I had the resonator wrapped for almost a year and although there was some breakdown on the fibers in direct contact the rest were almost new and the whole thing is still reusable. Now the outside of the resonator might be much cooler than the rest of the exhaust, or maybe the exhaust had enough time to cool before it got there. I wouldn't wrap the headers either too many problems on multiple levels.

It may not last long, but it's a cheap experiment and if I need to figure something better out I will. I'll keep you guys posted.

olddragger

iTrader: (3)

i did forget one thing--i do track my car --so my exhaust does get pretty hot while on track. A street driven car would probably have better results?

GK1707

iTrader: (10)

Unique build And have fun cleaning that paint off your driveway