WARPNOVA

iTrader: (3)

My car is mostly a weekend warrior so it will see a ton of street use and a little but hard track use. My goal is to obtain the upper 6xx rwhp level or more and have plenty of off the line power and torque for around town driving. From what I have read and seen it is easier to get this level of power out of the APS kit with larger cubes without having to turn up the boost so high. I would love to have a 402 but I don’t think that is in my budget along with all the other things I need. I guess my question is would the extra cost of a 383 be worth it or not over the 347?

My build I hope will look something like this.
Callies Crank.
Callies Compstar rods.
Mahle pistons.
Total seal rings.
Clevite Tri-armor rod and main bearings.
Clevite cam bearings.
ARP main studs with maybe a DM performance girdle plate.
ARP head studs.
GM 317 heads.
GM new 5 layer head gaskets or the Fel-pro ones.
Manley valves.
Partiot Gold extreme dual spring kit.
Harland sharp rockers.
TSP stock length pushrods.
GM Cadillac lifters.
Melling oil pump.
LS2 timing chain.
Cam is still in the air right now.
Stock LS6 intake and TB.
Speed inc rails.
Motron 60 pound injectors.
Lonnies double pumper kit with wireing kit.
Magnafuel regulator.
Roadrunner PCM with EFI live speed density tunning.

And of course the APS kit it's self.

Sharpe

iTrader: (7)

From what I've seen people run on here, I'm pretty sure the answer is no. Normally, people do 370's for boost, not 383's, but most people have 346/347's that I've seen. APS, I'm pretty sure I've read on here, would reccomend a 370 over a 383 or 402 even. Call and ask them. Also ask them what cam to run.

MY99TAWS6

iTrader: (3)

346 works fine. 383 will work fine..370,402 ,408..whatever your budget allows.
Bigger engine means more torque,better off boost, quicker spooling.Pretty much win win.

WARPNOVA

iTrader: (3)

That is what I want, more torque off the line for street driving and a better torque curve. I know APS doesn't recommend the larger engine as of the worry of maxing out the turbos. I believe that peter said something about the stroke on a 402 and 383 not being the most efficient for their setup.


I guess what I am trying to figure out for myself is would the gain from going to a 383 be worth it over a 347. I know if I was talking about a 402 that size of a jump is, potentially more worth it as can be seen in cars like JMBLOWNWS6.

Also I have searched but not many have really done 383's on turbo cars unlike supercharging. Is there something I am missing as to why 383's aren't very popular for turbos and if so please point me in the right direction as I have searched pretty far back but maybe I haven't gone far enough back? I was looking at posts from 05 about someone doing a 383 and T76 but it didn't have much of a conclusion.

MY99TAWS6

iTrader: (3)

I don't think APS or anyone else is going to keep dissing the standard APS kit anymore on a 346,370,402 or 408.Heck it might even do a decent job on a 427.JMs car is proof for sure. 10.21 at 137mph at only 10psi. Thats hauling the mail. And lots left in it..He wasn't revving to even 6000 and he can dial in another 8 pounds or so.And he is an auto so has higher drivetrain losses than m6.

Not really sure why noone messes with 383 much. Think most guys go to the ls2 and usually do a 402. Lots of guys do a 6.0 iron block and use stock crank and stay with 370. I just want to go one step farther and do a 408 iron block with forged crank. I am an overkill kind of guy. Not sure the 6.0 can go 427 very reliably for FI and don't want to go ls2 block or lsx so guess just be happy with 408.

There is zero reason the aps kit would not work great on a 383 so feel free to do that sure you will be impressed. You will gain torque on and off boost, you will gain spool up
and you should be able to make the same power as smaller engine at less boost.
You can get high power as I said with just about any reasonable size with the twin kit. And Peter is talking idea rod to stroke ratios or whatever. I have heard that before but would not overly worry about it. The main APS site says the system is suited for bigger engines and thought mentioned 4xx range.

Remember you can also do a 6.0 iron pretty cheap if you stick to stock crank.The stock cranks in the 6.0 have gone like 1000 engine hp.Then sell off your old motor to recoup some of the costs. I am just selling off my very low mileage ls1 engine. That should pay half the new shortblock or buy me my new strange dana 60.

calongo_SS

iTrader: (7)

Just b/c the APS kit will make 18 lbs on a 346 does not mean it will make 18 on a 40X. The turbos will probably max at well before 18 psi on a larger motor like that. They can only flow so much air, a larger engine has less restriction so there will be less boost pressure at the same airflow.
I do agree, JM's car is hauling the mail, and it shows that the standard kit will work no problem with a larger motor at 10 psi. We don't know yet what will happen or what the limit is when he turns it up.
I am completely happy with my APS kit, but am running on the stock bottom end for now. When it lets go, I will most likely be building a 347. There is no lack of tire shredding torque from a smaller motor with this kit and an auto. The turbos spool up FAST.

MY99TAWS6

iTrader: (3)

True we have not seen how high and how much power can be achieved at higher boost on bigger engines. So far APS dynos are on the forged 346. And just saw another one similar to JMs on that other 402 from EPP at 9.5 psi. So it may not get to 18psi. I have seen these 20gs boosted way past 20psi on dsm applications but of course that was single turbo on a 2.0 litre engine.
It will be interesting for sure. Of course in the real world I will be more than pleased to do a low 10 or high 9 at only 10psi in my planned 408. Most guys don't think want to go faster than 10s anyway on a street car. Thats freakin fast no matter how you look at it and especially in an almost two ton car that JMs raceweight was. And 9s is just stupid fast for the average guy.

So hoping to see exactly what boost he can get. I do think we have seen some higher boost numbers from LOBOOST and his GTO also. Forget what size engine he has don't think its a 402 ..366 or whatever I think.

ddnspider

iTrader: (26)

i love my 383 turbo setup.its nice to have power when youre not at full boost

WARPNOVA

iTrader: (3)

That is what I was looking for as I truely feel that the APS kit can handle the larger cubes up to atleast 402. But I am not looking for all out power and feel that anything 600 rwhp is going to be plenty for any street car and I am preaty certain will get me into the 10.xx range at the strip. And like you said nice power off boost, so that is what I feel would be nice for me and still hit that power level I am after.

Thanks a bunch everyone for your input and help I hope to get this thing rolling soon as I have already been stock pilling alot of parts.

peter@aps

iTrader: (2)

That's correct as the 370 has a more durable/safer cyl bore to stroke ratio for higher rpm then 383 or 402 engine. If you're not intending on running big rpm then the 383 or 402 engine will be very torquey for a daily driven street twin turbo engine.

Peter

Interlizer130

I also have a 383 turbo setup

Johnv

I'm in the process of building a 383 with a TC78