Thought I would share my Camaro plans

[skyhighsami]

As some of you might know I have a 98 Camaro SS that I am working on. I got it in Jan, I traded my Typhoon for it. The motor was a 402, that block is at the machine shop now getting worked. It was how do you say fucked. It will now be a 408 which is a 6.0 liter truck block with a 4 inch stroke and a 4.030 bore. I ordered the pistons, rings, and cam last Tuesday from VA Speed who has a good deal of experience with what an am building. The pistons are custom SRP forged with a -32cc dish 8.8-1 CR and the cam is a 236-236 cam with Total Seal rings for a boosted application. I am planning on putting on either one 88 or 91 turbo on it or running two 61s. The cam that I ordered will have me shifting at 6200 rpms. So I would like to make power from around 3k to 6200. Input please on what would be better for me single or twin. I know nothing about turbos. This project will take me awhile as I will be throwing ALOT of money at it. Being married with 2 kids comsumes alot more money that you would think. New tranny Viper internals, 9 inch Ford rearend, Suspension, wheels, tires, and brakes. Not to mention an all over paint job. So my plans are this time next year. I wasn't going to tell anyone and keep the build as quiet as possible but what fun is that. I will have pictures of the block when I get it from the machine shop within the next couple of weeks. Let me know your feedback, my goals are mid 8s whp low boost and close to 1k high boost with meth. Guys are doing that and more with less motor.

[dixond]

TWINS!!!
I know nothing about turbos, so I can't really contribute to this thread, other than to say that it sounds awesome.
Sounds like some serious money you're going to be putting into the car!

[phillyd]

A single snail might be better for a couple reasons...1. cheaper, 2. easier to tune, 3. huge turbos are the WIN

Twins might be better for a couple reasons...1. possibly quick spool and boost response, 2. if there are any fitment issues with have a large single 3. the coolness of having twins

I am a penny pincher, so I, personally, would go with the best performing/most economical hardware...but wither way the SS is going to be a sick beast!

Toss up those pics of the block when you get 'em.:steering:

[gangsta coupe]

Just a thought, but why if your going to drop this much cash on your setup did you order an ots cam? I have a buddy with a 408/88 combo and it has no lag anywere in the power band even at lower psi (4-5 psi)

[skyhighsami]

I guess OTS is off the shelf and if that is what you meant this is a custom cam from VA Speed. They have done several vehicles on LS1Tech with over 1k whp with a milder setup than I will have.

[ghostdriver]

what boost pressure are you gonna have to run on that motor for that kind of power?

[skyhighsami]

I am thinking low boost in the 15-18 range with the CR I will have. Turned up I am thinking some where around 22-25 with meth.

[Matt2105]

If it's mainly a fun street car, run twins. Mostly strip, run a large single. Being a 408, you wont experience much lag either way you go.

With your setup, I'd opt for a large single. Cheaper and will make more power. Not really a downside when it's matched to a 408.

What's the specs on the cam? LSA and lift?

Edit: If you go large, you may want to spin the motor a little farther. Definetely post this up at ls1tech. Im certain some people would love to hear about it sami.

[skyhighsami]

The cam is a Comp Cams 236/236 .615 .615 and I think the LSA is 114+4. I have been living on Tech ever since I got the car. My orginal plans was to make around 500 whp all motor and then spray it. But we ended up going into the motor so I desided that I would build it for boost. The rings I got were some Total Seal rings made for boost. They were 250 which is alot more than I was expecting for some rings. :D I too am leaning more towards running a large single because of the better power that it will make up top and the added lag hopefully aiding in traction. The biggest issue that I am having is my insistance to keep the AC. I could have it turboed in no time flat for very little money by just turning some stock manifolds around, but I would loose my AC. I refuse to loose my AC and put it an auto. I wanted this car because it was a 6 speed and it will stay a 6 speed.

[ghostdriver]

after playing with numbers and my turbo book i have to suggest that you go with a big single. it should spool about 200rpms faster high boost and only about 500rpms slower low boost than the twin setup (granted you pick the right turbo).

[skyhighsami]

And the right turbo would be what. What would be the best downpipe size and etc. You have sparked my interest. Here is a link of something like what I am going to build. I will have a sligtly bigger cam and better heads. http://ls1tech.com/forums/showthread.php?t=815119

[ghostdriver]

ive only looked at garrett so far and the one from them that works is a GT4708R. You want a ball-bearing turbo for sure. That turbo is ball-bearing and the numbers i crunched gave me 25psi 3k-6200 and 18psi 2500-6200.

As far as downpipes go i really dont know what size would be appropriate for your setup because i know nothing about average exhaust sizes for american iron. I bet that ls1tech forum would help out with downpipe. Might have other turbo suggestions too.

I think you would need bigger injectors than that guy and i really suggest meth/water injection. With the cam/heads being better i think its possible you will getter better response than my numbers say.

[2Fast4Radar]

4" turbo back exhaust at least if your goal is 1k-rwhp.

[skyhighsami]

I was going to upgrade the entire fuel system and use meth as well just so I could get by with more boost, and a smaller IC. Since the space under the hood is at a premium

[skyhighsami]

This is what the guy and I have come up with if we do a twin setup. We thought about doing 2 61 turbos with a .68 AR from a Grand National. The thoughts behind this is that those turbos were designed to be spooled off 235 CI. Since half of a 408 is 204 we thought that the backpressure ratio would be closer to ideal and would spool very quickly. Otherwise I was going to get either a Precision 88 or 91 with like a 1.28 AR I believe. Any bigger and I think spool time will suffer too much any smaller and I think I will be creating too much backpressure on the outlet. If I go twins right now the plan is 3 inch 3 bolt style downpipes with internal wastegates (neater package) If I got single I will likely only do a 4 inch downpipe anything more is too big for the street I would think. Besides that is why they make cutouts.

[2Fast4Radar]

The one huge turbo won't be as much fun unless all you care about is the drag strip. A single large turbo would be better off for a huge stalled auto. I'd much rather use smaller twins in your case because of spool time, maybe even smaller than 61's. No plans of nitrous?

[skyhighsami]

http://www.youtube.com/watch?v=rCb0vLo-N7E. No plans of nitrous and I would think that anything smaller than 61s wouldn't spool that well. If you look at the link they built a 67 Camaro similar to mine with less cam and less heads with those turbos and raved about how instant the boost was. I would like to closely mimic his build in the link above if I go single. They say with the big turbo that the lag isn't as bad as it would be on say a Supra. I would have over twice the motor spinning the turbo at 6.7 liters.

[ghostdriver]

the problem with the smaller twin turbos is that its hard to find two turbos that will hold the kind of boost you want for very long and spool in time. The only set i found by garrett that would hold the boost pressure through most of the powerband was two GT3076s. 25psi spool is 3200rpm. 18psi spool was 2k. since the 4708 hit 25psi at 3k i figured it was the better choice. Granted it does take until 2500 to hit 18psi. I thought the high boost application would be more important to you.

[2Fast4Radar]

They say with the big turbo that the lag isn't as bad as it would be on say a Supra. I would have over twice the motor spinning the turbo at 6.7 liters.This is true. You def need to figure out your ultimate power goal [93oct/racegas/meth] and then start shopping for turbos that can support it. You could easily make 750-800hp with a not so gigantic turbo.

[skyhighsami]

I have stated my ulitmate goal. How much sooner would the BB turbo be at full boost? The turbos I get will be Precision because the guy helping me is a dealer. So I can get them at cost

[skyhighsami]

Tonight I think I got a smoking deal on a Precision PT88 with a Turbonetics 60mm wastegate, headers and crossover pipe, new rad, A2W IC and all the related hardware, and a LS6 intake. I should know for sure if it is mine by the end of the week. I am getting everything minus the piping from the IC to the intake and the down pipe. All I would need then is the beefed up tranny, rearend, fuel and meth system, wheels tires, and suspension. The pistons, cam and rings should have shipped today so I should have them by the end of the week. Is there other turbo parts I might need other than a BOV?

[ghostdriver]

i honestly dont know how well you are gonna be able to spool that turbo without nitrous. i dont think 25psi is gonna happen. i hope that you can reach your power goals without that much boost. i think the journal bearing will be ok, im honestly not sure what the major performance differences are between that and ball bearing. i have always just been steered towards ballbearing.

[skyhighsami]

If you watch the link I posted that car has a 370 and a PT88. I would have 38 more CI bigger cam and better heads. So I am lead to believe that I would spool it faster and harder than he does.

[bzflag]

You should be fine on that turbo. I would have done the same if I could swing a deal on a journal bearing. You're only losing a couple hundred rpms of spool.

[Matt2105]

i honestly dont know how well you are gonna be able to spool that turbo without nitrous. i dont think 25psi is gonna happen. i hope that you can reach your power goals without that much boost. i think the journal bearing will be ok, im honestly not sure what the major performance differences are between that and ball bearing. i have always just been steered towards ballbearing.

He'll be fine. BB's usually only spool like what, 3-500 rpms faster depending on application.

I still think I'd swap the cam for something that peaks at a higher rpm, but thats just a minor detail.

Should make awesome power. You have to take me for a ride when you finish it Sami.

[ghostdriver]

If you watch the link I posted that car has a 370 and a PT88. I would have 38 more CI bigger cam and better heads. So I am lead to believe that I would spool it faster and harder than he does.


how much boost is that guy running? i was just telling you what the numbers told me. without factoring the cams and heads in you wouldnt get 25psi until around 5k. im not trying to shoot down your plans or anything i just think you might need to run less boost with that turbo. It will still flow better than a smaller turbo at the same boost.

[skyhighsami]

At 22 PSI he made 970 or 980. I have a PT88 with a .96 AR housing sitting right here right now!!! I am a little excited