foose04

iTrader: (4)

Timing is key in keeping them down. I got stock 862 heads, ls9 gaskets and ARP's on my 4.8 up to 22psi. Hasn't pushed a drop.

I also have stock 317s, just haven't sucked up the install.

I8UR4RD

iTrader: (16)

yeah I actually went with the 1/2 option for when I push a F1-A on it maxxed out. My CR is 9:6:1

PRAY HRD

iTrader: (119)

yea for a max effort i would do the 1/2" option on my own build but i'm working with an existing motor that already had these and it's not going to be a max effort setup any time soon. i just don't have the funds for a project like that. for now i'd be extremely happy with 800+rwhp and an 8.99 slip driving to and from the track. it wont be on pump gas for that power but the rest of the car is setup to handle the power so fingers are crossed! lol

TINKRD

iTrader: (27)

boost is more addicting then nitrous. i was happy at 15lbs on 93oct driving around making 850ish... for about 2 weeks. lol now 25lbs doesn't feel fast enough.

denmah

iTrader: (2)

3x 4.8l cars over 20lbs of boost on stock head bolts and gaskets, never had a problem.

others we are running arp bolts and stock HG's on 20-22lbs

I8UR4RD

iTrader: (16)

to run an 8.99 like that....what weight would you be running at. Because I am guessing a low 8xxrwhp on the dyno, and I was only expecting high 9's. Guess it really depends on torque. If you run in the 8's on that setup, and at that CR then I would leave it alone. My goal is 9's. I highly doubt I will run into any 8 second setups on the streets around here. .....longrange4u is running a 91mm butt mount making 1150rwhp and has been in the low 9's so far. I assumed it would take alot more than 800 to hit those times, and some strict dieting.

Too much is never enough!

westtexasbuff

iTrader: (40)

Where do you have your downpipe dumped?

TINKRD

iTrader: (27)

5in, dumped at trans.

PRAY HRD

iTrader: (119)

it will be a tad under 3400 lbs race weight. if i can run a 10.3x with 480 rwhp through a 4l60,and not enough gear, i'd be sorely disappointed to not run an 8.99 with the same weight, proper gearing and a th400 with a brake @ 800-850 at the wheels when all the calculators ( i know i know lol) say 800 should be enough for an 8.90 at 3400lbs. i'm hopeful but can always crank it up to get the time i'm looking for but 9's on pump and on the street is plenty for me as well.

longrange4u

iTrader: (2)

You would be 450lbs under my weight when I ran 9.4. And dont know what 60' is in your ride.. but I dont think you are skinny enough for an 8.9 run unless you are running a great 1.3x 60'.

What do I know though?? I am running HP #'s that should have me much faster... but I am dieting and gonna see if I can get my first 8.9 run in GA. Would LOVE to be at 3400 race weight... but fat chance (pun intended).

PRAY HRD

iTrader: (119)

LOL i got the pun! yes i wasn't gonna say it but at 1000 rhwp, 8's shouldn't be all that hard to come by but you definitely have some weight issues! my car was 3400 with me in it on motor last year and cut a fairly easy 1.37 60' but i don't know what to expect out of it now. comp will be dropped to about 10.2:1, 402 cubes, th400 w/brake (was 4l60), still on 3.70's to start with but likely will drop down to 3.08's cuz i cruise a lot, weight should be slightly under 3400 now after some weight reduction to offset the kit & turbo, and hoping for 850rwhp on race day/race fuel. plans are to get it lighter when it goes to the chassis shop too btw, which i should've mentioned. but that wont be til next year.

awesome car btw longrange!!

TINKRD

iTrader: (27)

bump from the dead for some discussion..

the last couple weeks i went out racing and logged a lot of files. One night in bed the light bulb went off about my boost. my boost never falls off through an entire pull. looking at 260ishKPA all the way to redline. what this tells me vs. the dyno graph is that backpressure or too small of an A/R housing isnt the issue. Otherwise the boost would start to fall down through the upper RPM's. Could this just a factor of the unported 317's? Falling out of their efficiency range?

thoughts?

TurboS10

iTrader: (12)

what rpm?

drop at end can be in no order -
fuel
BP
Reversion - cam timing and or BP
compressor off to the right
valve springs
ring flutter

my guess is springs

Intimd8 had a dyno curve that was pretty flat to ~7k on a 218/218 gen II

DR turbo says 4788 has BP issues "period".
But your the second person I've seen run well with 400CID. Other guy said 1.08 also.

This is making it harder for me to decide 370 or 347.

Sales@Tick

iTrader: (3)

This x1000

You're dynamic is pretty low with that 236/236 cam and the 8.5:1 static.

This is another reason why you could run 18* and as much boost as you did along with using C16.

This is why I always say timing numbers, boost numbers, etc. all depend on the combination as each one will be different and just because someone's cousins, brothers, step son's, auntie's, nephew ran 25psi on 18* with 4 bolt heads doesn't mean you can too.

Great combo, I like the simplicity and the power it makes for sure.

TINKRD

iTrader: (27)

hmm. wouldnt have thought valve springs. i dont remember what the spring pressure is on these. I didnt set the springs up myself. With the same cam and springs it ran n/a for a year or so. not spring float then. would boost effect this? never really had a discussion about seat pressure for n/a vs. boosted setups.

I would still think if it were backpressure then the psi would start to drop in the uppers RPM's. perhaps my understanding is wrong.

as far as RPM's, i dont have the log file from the dyno run, but if i compare to my highway pulls from last week:

4816 RPM's is 117mph
5867 RPM's is 141mph
6546 RPM's is 148mph

248-252kpa through the entire pull, so roughly 22psi.




there was a tire change since the dyno went from a 315/35/17 to a 325/50/15 (26in to 28in). but for comparison sakes, should be about the same. So roughly makes peak power at 5200rpms then drops off after that. looks to be making around 950rw at 6500rpms

TurboS10

iTrader: (12)

I thought you meant drop at the end -past 6k.
5200 usually means BP with that size cam, springs would have a wavy trace usually, but not always....best thing is to measure BP rather than f around guessing. Dial tire pressure gauge from auto parts store and some copper tubing w/fittings from home store doesn't cost much.

A 238 cam is usually around 6800 peak on a stock 6.0 from the posted graph's I've seen.

Killer_LS1 has a 408 with bigger turbine 88mm than you with a 231/227 cam an he peaks at 6250 on a dynojet. never really goes flat IIRC.

The link below is a 347 ford, afr 205's. -flow numbers similar to LSx AFR 205's but I'd guess the chamber and steeper valve angle will make less power, and a .008 tight lash solid roller 236/230.
see post 110 in link below. see 1st post for specs. He goes 8.79 later in the thread. To me it backs up what DrTurbo among others has been saying about the 4788. -BP at 6k even on a 347.

http://www.theturboforums.com/smf/th...ack-times/105/

see post 58 & 59. This is 347 with 91.5 F trim? and low 240 HR.
http://www.theturboforums.com/smf/th...and-a-nova/35/

not hate'n your setup at all 1k is 1k, just commenting/theorizing. -I'm back to a 347 again.

TINKRD

iTrader: (27)

thanks for the info! I’ll look into those thread. Not taking your post as criticism at all. This entire build was with off the shelf budget parts. it’s by far exceeded my expectations along with a lot of other folks as well.

TINKRD

iTrader: (27)

that's the 1st thing people ask me when it tell them unported 317's, 4bolt heads and 22psi. lol "how much water do you push?"

6ltr

Off topic question

Who built your turbo kit?

Sales@Tick

iTrader: (3)

Boost has a huge effect on the springs that should be used.

You're creating more cylinder pressure than you ever could N/A.

What lift are your springs good too and what lift is your cam?

If you have plenty of room to shim them before you reach coil bind, I would for sure shim them to raise the seat pressure.