Ive been building up a Low compression 427 sbc, and should have about 480 - 500hp N/A. After about a month of debating on procharging vs. Turbo, I decided that I wanna Twin turbo it. Im just stuck on A/R sizes. I was kinda looking at Turbonetics 62-1 with either A/R .81 or .96 I just dont want to go to small and choke my motor up top, or have it build up that much boost below 3k either. I should have plenty of bottom end power, so i Don't need to build boost at low Rpms. I want to start building boost around 3000 rpms upto 6.5K. I also need the Twin turbos to support at least 800 - 850hp, since thats my goal. The most boost im going to run will be 10 -12 psi intercooled. Any help with Turbo recommendations, A/R sizes, and what to use to build boost from the Mid to Upper RPMS would be appreciated

 

i'd just put a big single turbo on there and call it good.

 

Yeah i thought about a single turbo. But i want the eye candy of a twin. I know I probably won't be able to delay the boost buildup as easy using 2 medium turbos, but im more concerned about having enough airflow in the upper Rpms. I'm thinking them 2 Turbonetics 62-1's with the A/R .96 will push the initial boost back a little and give me a bit more breathing room uptop. Any of you Turbo studs have any thoughts or turbo options you might recommend??

 

www.theturboforums.com


start researching builds for probably 40 hours or so before asking any questions and you'll figure most of it out.

 

If you want turbonetics turbos then you can call them and tell them what you are looking for in terms of boost vs. rpm. Those turbos are going to cost you dearly. What are you estimating the cost of the engine build for the 427ci without the turbo setup?

 

about $10k on the motor alone,
Block (2,200)
Rotating assm (3000)
Heads (1500)
Cam (350)
lifters (350)
pushrods (100)
rockers (400)
rocker nuts (50)
Head studs (150)
Timing set (150)
Rod/main bearings (150)
Harm Balancer (350)
Pan (250)
oil pump (85)
other stuff not mentioned ($1000)

Probably another 5k or so on the turbo setup. I dont mind the price on Turbonetics, they also got a 1yr no questions asked warranty that i like.

XPNDBL3: Thanks for the link, Ive been on turbomustangs and 2 other sites the last few nights. Learning alot more each day

 

62-1s will take you to 800rwhp no problemo. I would probably size conservatively on the tubines tbh, you have a lot of "good" parts there but at the same time I'm not unsure if you may even like the .68s. That being said with the choices you gave I'd probably do .81s. Then again, if you purchase off center P trim turbines it should be pretty easy to get someone to swap you up/down in size if you're not right.

Are you getting headers built or buying them? If you're building your own logs work well but I would suggest a pulse tuned setup consisting of putting the center 2 ports on each side to one side of the turbine scroll, and the outer 2 ports into the other. This makes the pulses more "defined" and should decrease both your overall back pressure and cause it to spool faster.

 

Drac0nic: thanks for the help and valuable input. Ill look more into the .81s. Im thinking Ball bearings are a must also, and it would help it spool quicker with the larger turbines. Im not sure about headers yet, but this "Pulse Tuned" setup sounds interesting. Im going to look into that more.

 

Don't take this the wrong way...but a 10K engine + 2K fuel sysem + 5K turbo setup. Are we talking reality here or the ultimate dream setup? How much of the engine is assembled already?

 

im not working with a limited budget by any means, if thats what your trying to figure out. I have everything for the motor, except the intake, headers, elec water pump, and distributor. I might hit up the carb shop and have them tune up something for me. Besides that, i do need to plumb my fuel lines to 1/2" still, but im not sure if the camaro will be gettin this motor. Im looking around for a good full framed Nova, chevy II, or 1st gen camaro

 

1/2" fuel lines isn't going to cut it at all. I'd be looking -10 or -12 for feed lines. I maxed out my 1/2" feed line on a 350 engine without a lot of nitrous.

 

Really? Cause im running the 383 setup in my sig on 3/8" fuel lines and a 125 shot of nitrous just fine. Ill definatly do some research into them fuel line sizes and what would work best. Do you think i should go with one big line, or try running dual lines and 2 fuel pumps?

 

depends if you plan on street driving it a lot. A bunch of guys on that other site are running 2 A1000 aeromotive pumps on the high HP builds. I'm just going to run a single A1000 with -10 lines for the spring on my camaro. Otherwise there are pumps that put out a ton more fuel, but aren't made for continuous duty.

 

Yeah i was leaning toward the A1000 also. My camaro is pretty much a summer night car btw. But it will see plenty of road time, so continuous duty is a must. I think i finally got my turbo setup figured out too. So Xpndbl3, What are you doing to your camaro thats going to require you to use them -10 lines??

 

just 2 small turbos, nothing fancy, but I wanted to get away from $$$ nitrous refills, and with turbos I can switch from 4.11 gears down to 3.50 or even 3.25 gears, so I will get a ton of driveability back. Probably have to size down on my converter as well but I think it'll be worth it. It'll be slower with the 2 small turbos than it sat last year, but I think I'll make up for it with being able to drive it more.

 

the a1000 doesnt do too well I smoked mine.......if you use it DEFINITELY get the pump controller unit from aeromotive as well....it'll last alot longer. the Eliminator pump puts out alot more volume.
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you using the dart little M? I think i paid 2300 for mine, with the billet steel 4 bolt caps......and i got it at cost.....things aren't cheap haha

 

yeah i hear that, nitrous does get pricey after awhile. Im doing the exact same thing as you with the gear swaps. The 3.73's i have now are annoying enough when im forced to get on the interstate. And I top out quick without overdrive. Im debating on 3.25's when this motor is done, possibly 3.00's. I know Moser lists that the highest gearing you can get is a 3.25 with their 9 inch rear ends, so i might call them and see if they do offer 3.00 gears just out of couriousity.

 

I know you have had alot of experience with high HP setups, so ill seriously look into that pump controller. No them Blocks aren't cheap at all lol. Exspecially when you see new stock blocks for 1/4 of the price. But i do believe you get your money's worth when it comes to Aftermarket blocks. Ive been following your build for awhile now. Almost makes me wish i woulda went with a big block crank lol. That looks beefy and bad as$. I dont think it will be AS much of a problem for me since im not running a procharger, but never say never right. I know your not a big fan of them, but i ended up going with a World block. How do you like your Heads? I went with the same ones.

 

That pump controller is the ***** man, It's easy to wire it up and it works flawlessly......it has an override switch on it to go from low speed, to full power on the pump for the track....and if you leave it alone you can set an RPM at which the controller will automatically switch to highspeed.....I think mines at like 3500rpm......keeps the pump cool, and makes it live a long life on the street.

I don't have a ton of experience with the world blocks, but I've just been overly impressed by the dart ones for quite awhile......with aftermarket blocks though you definitely get what you pay for, the strength on every part of the block is an order of magnitude better....blind head bolt/stud holes in the deck, so you dont need sealant....siamese bores, huge main webs etc. but yes, they certainly don't come cheap.....THEN you have to finish machine the thing haha.

I don't think you're gonna have to worry about the BBC snout with a turbo, alot of people have been using that setup in racing in general for a long long time, but without a blowe drive its not a necessity.

The heads are the early design AFR 210's with the full cnc port job.,......even these make ridiculous power.....the naturally aspirated version of the motor with a MUCH smaller cam, made over 500hp at the crank. It's a really good head, and the new eliminator ports are just insane.

Preston Smith just got his car back together with a new set of the eliminator heads, considering that car was making damn near 1,000hp already with heavily modified iron heads......i'm really interested to see how it runs this year haha.....i'm going to an annual gearhead dinner thing with him next weekend, i'll find out then.

good luck with it man, it's definitely alot hard to do a build like this than people think it is, but its fun to build one of these things with good parts and have that peace of mind.....can't wait to see how it turns out.

 

thankyou 383backinblack. I appreciate your help. It's alot of fun to get all this rolling, and im learning alot more than i ever thought i would. It took a couple years before i had the funds saved up to do everything, but now i don't have to worry about half as$ing anything, and i can just focus on doing it right. Likewise with your project... I can't wait to see the numbers you lay down with your build. You'll have to let me know the new number's Preston is putting up. Thats just crazy.

 

thanks man, no problem......i look forward to seeing your setup in action with the extra cubes....we toyed with the idea of going much bigger since we had to order the crank and bore the block anyways......but we decided that cost-wise with new pistons and stuff, it just wouldnt be that big of a difference....once you're over 1,000hp i mean what the hell do you want haha.

you did it right man.....thats how i've ALWAYS done projects....wait until I have all the cash IN HAND, then start building.....that also gives you some serious time to think, plan, learn, re-plan etc....before you spend a dime.

Smitty is normally pretty tight lipped about numbers, but he can't hide it once the track opens.....i'll do my best to pry it out of him though lol.

 

Sounds like an awesome build. With boost it never hurts to go big with the fuel system. My friend is running two a1000 on his twin turbo setup where one kicks in under high boost. Can't say too much about it getting too hot because of the lack of driving he got to do this past fall with it. He is running twin t-67's on his 351. I think the AR is .68 on his so he builds boost by 3000rpm. Your motor is larger so you can run a higher AR I am sure. Just so you know with the wastegate open he still makes 10psi so that is the lowest it can go. Those turbo's should be good for that power level no rpoblem. Maybe closer to 900whp shouldn't be a problem.