twin turbo chevy

[dune333racing]

I have a 1969 large journal 327. Basically stock rebuilt bottom end with forged pistons w/ pressed wrist pins and ARP rod bolts. I plan on using some ported and polished 882 castings cut for bigger valves (2.02 Intake,1.60 exhaust) and screw in rocker studs. My compression ratio should be 8.25 to 1.

 

I want to run 12 lbs of boost, but I was told that pressed on wrist pins will break and stock rods will bend or break. It was said that iron castings do not like a lot compression and that I needed a floating style wrist pin and h-beam rods. I just want to know if this has merit or if this person was just trying to sell me somthing.... I have some pics ask if you want to see

[rustorbust]

If its a original large journal 327 than im pretty sure its a factory steel crank which is good and should take some kind of beating. Also if it is a large journal crankshaft than you can use 350 rods, you can usually find a set of powedered metal rods off of ebay pretty cheap. I have been using a set for a while in my 400 race motor and they havnt gone away yet. Not sure what to tell you about the wrist pin though. Never really heard of people having that problem, I have put alot of motors together with pressed wrist pins and no problems with them.

If it was my motor I would do it with the stock setup, but thats just me. I always want to see what a original small block will withstand...which i have found is to be more then what people usually think.

[rustorbust]

what pics do you have?

[dune333racing]

here are the pics i was talking about...I found a nice set of twin turbo headers for cheap..

[grumpyvette]

chevys powdered metal rods for the sbc are significantly weaker than a set of aftermarket (H) style rods with floating pins and FORGED PISTONS that you should be useing in a turbo combo,the forged crank you have is about 40 years old, it may be fine but ID have in carefully checked when the assemblys ballanced with the new rods and pistons (which you REALLY SHOULD GET)

keep in mind that rods normally fail long before cranks do, and that the weakest point on most stock rods are those lousy 3/8" rod bolts, aftermarket rods with 7/16" capscrew bolts can be and frequently ARE 50%-to WELL over 200% stronger than factory rods.

 

http://www.cnc-motorsports.com/category.asp?CtgID=4203

 

http://www.cnc-motorsports.com/product.asp?ProdID=8089

 

http://www.cnc-motorsports.com/category.asp?CtgID=4203

 

http://www.flatlanderracing.com/manleyrods-steel01.html

 

http://www.flatlanderracing.com/manleyrods-steel01.html

 

and the great news is they don,t cost much compared to getting stock rods resized and arp bolts added, and bushedc for free floating pins, all that costs more and gets you less in a powdered metal rod with 3/8" rod bolts

 

btw even ported and pollished 882 castings will cost you a great deal of power compared to a good set of heads, on a turbo you might want to look into the platinum heads as they give great potential for the cost

 

http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?catalogId=10002&storeId=10001&categoryId=27305&parentCategoryId=10187&langId=-1

 

 

both can be ported, and remember with a turbo and correct gearing you don,t have to worry nearly as much about low air flow port speeds, but the restriction to flow at high boost can be significan with small port heads

[dr_hunt]

Grumpy's right on the rods. Personally I don't like the PM rods. My banks' twin turbo kit was made in the early 80's and their kit on a stock 350GM motor with 882 heads made 761HP on 16lb boost intercooled on pump gas. Granted better heads will work better and darts will work better than the stock heads, but the dart's have such lousy exhaust flow and I/E flow percentages, that they will at some point become the restriction as compared to better heads like the edelbrock victor jr., brodix, afr, canfields. But it all comes down to $$$ and how much boost you plan on running.

[280zwitha383]

here are the pics i was talking about...I found a nice set of twin turbo headers for cheap..

 

How cheap and do they have more?

[silicone boy]

Having done this before, I would say that you should definitely take grumpy's advice (always a good thing to do). You want a bulletproof motor, especially if you plan on running that much boost. The headers look nice, but I built several sets of headers for the Z engine bay before I got a configuration that would work--I found that log style headers are pretty much your only option (see the Turbomeister's) or my easy solution. There's not much room for all of the turbo plumbing. You may have to heavily modify those headers or go custom, which I ultimately did. I don't mean to rain on anyone's parade, but I've spent the better part of 3 years getting this darn thing running and I've run into every roadblock imaginable.

[dune333racing]

My headers were 300 dollars on ebay. I found the best ones to buy are for a 82-92 Chevy camaro.....http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1,1&item=8044792407&sspagename=STRK%3AMEDW%3AIT

[280zwitha383]

You used these on a Z?! I wondered if they would fit but when they were posted last someone said they "doubted" they would fit.

[boodlefoof]

I wonder why it is that these headers are only around $300 whereas almost all other commercially sold headers for turbo applications are closer to $1,000? Is it because of the design being less than ideal (primary lengths being so different)? But even the Banks turbo manifolds are around $800 if I remember right though.

[dune333racing]

I have not tried them yet but they kinda tuck in close to the engine so I thought maybe I try them since they were so cheap...

[dr_hunt]

I wonder why it is that these headers are only around $300 whereas almost all other commercially sold headers for turbo applications are closer to $1,000? Is it because of the design being less than ideal (primary lengths being so different)? But even the Banks turbo manifolds are around $800 if I remember right though.

 

If you get the cast iron ones, they are $900, stainless is $1800. 1/2" thick flanges, weld joint pipes all real nice, great fitment, just interferes with the strut tower. I have an idea that a guy could make some much the same but bring them farther forward to fit better.

[dune333racing]

I think I will run what I have maybe with some turbo gaskets and ARP stud kits for the bottom and top.....

[Lason]

I hope you have better luck with those ebay headers than everyone I have heard from. They have all (except one) reported their headers have cracked after light use. The reason is because even though they are advertised as stainless, the flanges are not. Given stainless and mild steel have different expansion rates when heated up they will crack. Im contemplating a single or twin setup on my Z and the headers will be custom all mild steel coated headers.

[silicone boy]

Another TT W8 on the way? Awesome.