383 HSR with 4inch Dynatech Split flow
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Joined: Sep 2003
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
383 HSR with 4inch Dynatech Split flow
Well here is my nasty creation that i've been working on for last 7 months. FINALLLY STARTED!
FIRST start up this weekend but its leaking oil out the back of the manifold badly...so i gotta reseal that.
Specs are in the vid, but here's some more info. For those who havent been following the build, see pics in the sig to my webshots album
See garage link in sig for info on the build but rough specs i'll list
11:1 383 with AFR 195 Eliminators
230/245 custom grind hydraulic roller .603/.613 lift 109+1 LSA
Ported Stealth Ram
Hooker longtubes
into my own fabbed up y pipe. 3inch into 4inch flowmaster y collector
Dynatech split flow muffler mounted before axle
Dumped over the axle right now but will be dual exits like i had before
http://media.putfile.com/383-Stealth-Ram-Startup
VID does NOT do it justice... its very loud, very mean, and very erratic at the moment. I only have a base tune right now and it needs some work. IDLE rpm is set for 900 but in the vid its bouncing between 950-1150ish rpms with it mostly staying at 1050 or so but its alittle erratic
FIRST start up this weekend but its leaking oil out the back of the manifold badly...so i gotta reseal that.
Specs are in the vid, but here's some more info. For those who havent been following the build, see pics in the sig to my webshots album
See garage link in sig for info on the build but rough specs i'll list
11:1 383 with AFR 195 Eliminators
230/245 custom grind hydraulic roller .603/.613 lift 109+1 LSA
Ported Stealth Ram
Hooker longtubes
into my own fabbed up y pipe. 3inch into 4inch flowmaster y collector
Dynatech split flow muffler mounted before axle
Dumped over the axle right now but will be dual exits like i had before
http://media.putfile.com/383-Stealth-Ram-Startup
VID does NOT do it justice... its very loud, very mean, and very erratic at the moment. I only have a base tune right now and it needs some work. IDLE rpm is set for 900 but in the vid its bouncing between 950-1150ish rpms with it mostly staying at 1050 or so but its alittle erratic
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From: Waynesville ohio
Car: 1986 corvette Z51
Engine: L98
Transmission: doug nash 4+3 speed
Axle/Gears: 3:42 posi
Re: 383 HSR with 4inch Dynatech Split flow
Dude your car is bad ***! I want to build my car like yours. Right now i am a sophmore in high school. So i was woundering how long it took you to make it a beast how it is now?
thanks
kevin
thanks
kevin
Thread Starter
Joined: Sep 2003
Posts: 25,895
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
summer 03 i had the car, then catback exhaust then suspension work. next year i replaced tranny and torque converter. had some gears installed sometime between then and 05.
car remained the same basically till 07 when i got the Stealth ram and new exhaust/drag rims/tuning stuff etc.
this build took me 7 months but i took my time and had to save money little bit at a time. Dec 07 i tore the L98 down and started collecting parts from jan 08 till last month and still getting parts
Shortblock came in end of march/first of april and had it assembled by end of april but didnt get it in the car till may. Finally started today and its nowhere near 100% donenow that i got a "real" job aka one that i went to college for, i have some good money coming in now so i can really start to work on the car. If i had a job earlier, i would have had alot more done by now

Thanks for the props
Joined: Jun 2002
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From: Harford County, MD
Car: camaro sportcoupe
Engine: 7.0L
Transmission: G-Force GF5R
Axle/Gears: Moser 9"
Re: 383 HSR with 4inch Dynatech Split flow
justin it's looking and sounding great! i can't wait till i get me college job, lol!
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From: IL
Car: 91RS, 91RS
Engine: 305TBI, 3.1MP
Transmission: WCT5, TH700
Re: 383 HSR with 4inch Dynatech Split flow
Nicely Done....
Has a great tone. I bet when you get the tune better and drop your idle down that thing will be all chopped up and nasty sounding.
Has a great tone. I bet when you get the tune better and drop your idle down that thing will be all chopped up and nasty sounding.
Thread Starter
Joined: Sep 2003
Posts: 25,895
Likes: 429
From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
Thats what i cant wait to hear
i think it will idle great at 900 rpms where i intend to settle it to. we'll see how low i can get it to work at. that 109 LSA does chop nicely
i think it will idle great at 900 rpms where i intend to settle it to. we'll see how low i can get it to work at. that 109 LSA does chop nicely Supreme Member
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From: Cypress, California
Car: 1989 GTA
Engine: 369 TPI
Transmission: 4L60E
Axle/Gears: 3.70 Nine Bolt
Re: 383 HSR with 4inch Dynatech Split flow
That is very good news about your car. Looks like you are making good progress and it sounds so good.
About the oil leak make sure there is enough sealant around the area where the old oil pressure sending switch used to go. Also the areas at the end of the head gasket.
Also down the road you will probably want to open up the neck of the air intake where the round part meets the flat area. There is a big restriction in that area on Camaro's.
Can't wait to see the dyno and track results.
About the oil leak make sure there is enough sealant around the area where the old oil pressure sending switch used to go. Also the areas at the end of the head gasket.
Also down the road you will probably want to open up the neck of the air intake where the round part meets the flat area. There is a big restriction in that area on Camaro's.
Can't wait to see the dyno and track results.
Last edited by 1989GTATransAm; Jun 16, 2008 at 10:21 PM.
Thread Starter
Joined: Sep 2003
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
yep pulled the manifold today and resealed everything.. think i had a weak spot of rtv bead so i got it good this time with Right Stuff. worked great before and i hope it does good this time around.
I will see how the stock TPI box does with this car but i expect 10-20 hp loss thru that small hole. I plan on doing what TGO member DOC has done to his car...make a larger custom MAF sensor and recalibrate the tables. Hopefully it works. Thinking 3.5" MAF
Or else convert to 411 ecm from a LS1, the OBDII system. Looks interesting
But i'll drive it tomorrow if it doesnt leak oil anymore. good news for me
cant wait. I'll try to tune the idle more and if it settles down i'll get more vids
I will see how the stock TPI box does with this car but i expect 10-20 hp loss thru that small hole. I plan on doing what TGO member DOC has done to his car...make a larger custom MAF sensor and recalibrate the tables. Hopefully it works. Thinking 3.5" MAF

Or else convert to 411 ecm from a LS1, the OBDII system. Looks interesting
But i'll drive it tomorrow if it doesnt leak oil anymore. good news for me
cant wait. I'll try to tune the idle more and if it settles down i'll get more vids Supreme Member
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From: Houston Area
Car: Faster
Engine: Than
Transmission: You!
Re: 383 HSR with 4inch Dynatech Split flow
I looked through some of your pics. Please tell me you are going to ditch the stock injectors....
I recommend Ford SVO 30 lb. injectors for your motor.
I can also help with your tuning issues (PM me about that).
You are also going to need that motor to breath and might want to make something like this... https://www.thirdgen.org/forums/tpi/...pi-camaro.html
Looks and sounds nice by the way, good job!
I recommend Ford SVO 30 lb. injectors for your motor.
I can also help with your tuning issues (PM me about that).
You are also going to need that motor to breath and might want to make something like this... https://www.thirdgen.org/forums/tpi/...pi-camaro.html
Looks and sounds nice by the way, good job!
Thread Starter
Joined: Sep 2003
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
what pics did you look at? lol i have RaceTronix 42 lb injectors now, but they do sorta look stock like
And yep, stock TPI air intake box should be restricting. I'd love to either make a custom CAI with larger MAF or do that box that you have came up with. We'll see what it does with the stock box, then i will go ahead and make something and see if i get any more power out of it. Should be a good comparison
And yep, stock TPI air intake box should be restricting. I'd love to either make a custom CAI with larger MAF or do that box that you have came up with. We'll see what it does with the stock box, then i will go ahead and make something and see if i get any more power out of it. Should be a good comparison
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From: Cypress, California
Car: 1989 GTA
Engine: 369 TPI
Transmission: 4L60E
Axle/Gears: 3.70 Nine Bolt
Re: 383 HSR with 4inch Dynatech Split flow
The local guys have found 7-8 horsepower with a modified airbox over the stock one on a chasis dyno. In your case with a well built 383 I would expect a much larger gain.
In fact with the computer simulation dynos the CFM intake of a 383 motor is what limits the horsepower in the upper rpm ranges. So if your are going to be spinning your motor well into the 6000 rpm range it will need all the cfm you can give it.
In fact with the computer simulation dynos the CFM intake of a 383 motor is what limits the horsepower in the upper rpm ranges. So if your are going to be spinning your motor well into the 6000 rpm range it will need all the cfm you can give it.
Thread Starter
Joined: Sep 2003
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
well guys the split flow muffler idea is getting scrapped
fixed the oil leak today and took it on the street for a round the block trip and my god is it nasty. i dont think i got near 3000 rpms and i couldnt hear myself think...nor could the neighborhood.
NOW WHAT? what muffler to try? i'm thinkin dynomax ultraflo round.. 6inch packing round case, not the 4inch bullet
OR finish the tail pipes and put mufflers on each of those
fixed the oil leak today and took it on the street for a round the block trip and my god is it nasty. i dont think i got near 3000 rpms and i couldnt hear myself think...nor could the neighborhood.
NOW WHAT? what muffler to try? i'm thinkin dynomax ultraflo round.. 6inch packing round case, not the 4inch bullet

OR finish the tail pipes and put mufflers on each of those
Thread Starter
Joined: Sep 2003
Posts: 25,895
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
well that idea is pretty much not taking off either
i wanted to tuck them up like vettes have them but i'm not seeing the room to do so.... ARGHH this car is killin me
I got the y pipe over the axle...so i'm ready to make 3inch dual exits like i had before. just thought i could stick mufflers there but i dont think so now
http://store.summitracing.com/partde...5&autoview=sku
thinkin of that..it wil fit where the dynatech is and has more packing so it should be abit quieter
i wanted to tuck them up like vettes have them but i'm not seeing the room to do so.... ARGHH this car is killin me

I got the y pipe over the axle...so i'm ready to make 3inch dual exits like i had before. just thought i could stick mufflers there but i dont think so now
http://store.summitracing.com/partde...5&autoview=sku
thinkin of that..it wil fit where the dynatech is and has more packing so it should be abit quieter
Last edited by Orr89RocZ; Jun 17, 2008 at 10:08 PM.
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From: Kansas City
Car: 1991 Trans Am
Engine: L98
Transmission: T56
Re: 383 HSR with 4inch Dynatech Split flow
What about running a regular catback with a cutout? Still good performance but will be quieter and easier to route.
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From: NC
Car: '91 Camaro Z28
Engine: 383 Vortec HSR
Transmission: Pro-Built 700-R4;Vig 4000 stall
Axle/Gears: Moser M9 9" / 3.89
Re: 383 HSR with 4inch Dynatech Split flow
Sounds badass man, glad to hear the new motor is up and runnning!
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From: Hou. TX
Car: 86 TA, 91 B4C
Engine: 5.3, 4.8
Transmission: 4L80 4000, T56
Axle/Gears: 4.30 M12, 23.42 10 bolt
Re: 383 HSR with 4inch Dynatech Split flow
Man, i bet you have soe money in that thing. I wonder why it cams so fast? My cam is bigger than that and it is calmer. Might be because mine is carbed maybe with a 112 lsa?
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From: Charleston, SC
Car: '85 TA
Engine: 350 turbo
Transmission: T56
Axle/Gears: 3.70 posi 9bolt
Re: 383 HSR with 4inch Dynatech Split flow
I remember having that boat exhaust sound lol. What I used was a Magnaflow muffler where the stock cat would be. Made it a lot quieter & deeper tone. I also have a turbo and that makes it quiet too though, oh well. But, great job on the build and I'd love to check it out sometime.
Re: 383 HSR with 4inch Dynatech Split flow
I've heard that a couple of bullet style mufflers will fit side by side in the OEM location. Have you considered that option?
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
i ordered the dynomax.. we'll see how it sounds this weekend. and yes i have some coin in this car
Its not done yet tho
And it idles high because something is not quite right in the tune or i have a vacuum leak or something. during timing adjustments with the dizzy, when i had it all the way below 10 degreees base, the car idled choppy and lower rpm.
sounded good. but i'll work on that
Now its time to do more breakin in
Its not done yet thoAnd it idles high because something is not quite right in the tune or i have a vacuum leak or something. during timing adjustments with the dizzy, when i had it all the way below 10 degreees base, the car idled choppy and lower rpm.
sounded good. but i'll work on thatNow its time to do more breakin in
Thread Starter
Joined: Sep 2003
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
ok, took it for a little drive and break in session. Car feels like a absolute gorrilla!! Just mean!
I did the ring break in procedure that is recommended by GM performance parts as well as many other guys out there. Drive it hard early to help the rings set. By hard i mean do some pulls in a gear from light acceleration to medium hard acceleration adn let off in gear and let the engine slow itself down. vacuum helps oil the rings and helps them seal up against the cylinder walls i guess. Did a few pulls to 30mph or so then moved to 40, keeping rpms from 2500-4500 depending on what pull i was doing.
Anyway the car is breaking in and sounding better.. may have toned down a tad but its still very loud at part throttle and higher rpms. Idle isnt bad but any gas and its screaming.
Cant wait to try the other muffler this weekend
I did the ring break in procedure that is recommended by GM performance parts as well as many other guys out there. Drive it hard early to help the rings set. By hard i mean do some pulls in a gear from light acceleration to medium hard acceleration adn let off in gear and let the engine slow itself down. vacuum helps oil the rings and helps them seal up against the cylinder walls i guess. Did a few pulls to 30mph or so then moved to 40, keeping rpms from 2500-4500 depending on what pull i was doing.
Anyway the car is breaking in and sounding better.. may have toned down a tad but its still very loud at part throttle and higher rpms. Idle isnt bad but any gas and its screaming.
Cant wait to try the other muffler this weekend
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Joined: Sep 2003
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
kind of what it looks like.... gotta rehang the muffler as its angled downward too far in the back.. was tucked up nicely but welding i think warped the Y pipe downward so i gotta either bend it up or fab a piece to straighten it
still gotta bring the pipes out the back and get some tips like before
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From: Winston salem, NC
Car: 1987 1SICIROC.....1999 TransAm
Engine: 385 HSR.....LS1
Transmission: 700R4 with Midwest 3400 2.4str...M6
Axle/Gears: SLP Zexel Posi unit 3.42's...3.73's
Re: 383 HSR with 4inch Dynatech Split flow
ah? so you got 2 y-pipes? kinda like a borla setup?
Thread Starter
Joined: Sep 2003
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
yes a 3inch pipe from each header going into a y pipe into a single 4 inch into muffler then over the axle into 4-into-dual-3's y pipe, basically the same y pipe that is in the front of the car but reversed direction so i can retain dual outlets like this, my old setup
Joined: Jun 2002
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From: Harford County, MD
Car: camaro sportcoupe
Engine: 7.0L
Transmission: G-Force GF5R
Axle/Gears: Moser 9"
Re: 383 HSR with 4inch Dynatech Split flow
justin, i would SERIOUSLY consider putting the pipes all the way out the back before pulling the muffler. that thing sounds badass and i would think that the tail pipes would tone it down a little bit, cause right now that sound is bouncing around and getting caught under the bumper cover, causing lots of interior noise.
Thread Starter
Joined: Sep 2003
Posts: 25,895
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
well we'll see. The way i have it setup i could swap in a muffler in like 5 minutes
its all in components so i can tear the exhaust off if need be.
i'll see what i can do this weekend or later tonight.. i may try to finish it up tonight since i got some 3inch pipe/bends laying around
but i tell you what, when you get this thing goin near 4000 rpms on the street under some throttle, it sounds sooo good. Most aggressive car i've heard in awhile :0
its all in components so i can tear the exhaust off if need be.i'll see what i can do this weekend or later tonight.. i may try to finish it up tonight since i got some 3inch pipe/bends laying around
but i tell you what, when you get this thing goin near 4000 rpms on the street under some throttle, it sounds sooo good. Most aggressive car i've heard in awhile :0
Re: 383 HSR with 4inch Dynatech Split flow
I've never heard about that break in procedure. How long do you do that for? I doubt I need to do that as I'm only changing the H/C/I on my motor. Sounds interesting though.
Thread Starter
Joined: Sep 2003
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
yeah its just for a new motor
http://paceperformance.com/index.asp...=Custom&ID=636
can read some of the advice here
https://www.thirdgen.org/forums/tech...tor-break.html
http://paceperformance.com/index.asp...=Custom&ID=636
can read some of the advice here
https://www.thirdgen.org/forums/tech...tor-break.html
Joined: Aug 2006
Posts: 12,805
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From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Re: 383 HSR with 4inch Dynatech Split flow
tell me you didnt remove the upper panhard bar
Thread Starter
Joined: Sep 2003
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
no its still there, you can see it cant you? besides i know ppl do that on 4th gens with no adverse effects, especially on more drag oriented cars
mine is dual purpose
mine is dual purpose Supreme Member
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From: p'cola FL
Car: 88 iroc-z/28
Engine: 408 lsx
Transmission: 5800 stall
Axle/Gears: 4.71
Re: 383 HSR with 4inch Dynatech Split flow
alright, now that weve seen and heard the open header vid, lets here it with the muffler on!
sounds wicked.
hows the resonance in the car?
sounds wicked.
hows the resonance in the car?
Thread Starter
Joined: Sep 2003
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
its got a lot of interior noise at the low rpms, mainly between like 1500-2500 or so. when you mash on it over 3500 the outside volume has to be on the order of a demon spawn from hell haha, but its not loud anymore on the inside when on the throttle.
I would love to get rid of that resonance. I'll take out the CD player now as there is no way your gonna hear that.
I would love to get rid of that resonance. I'll take out the CD player now as there is no way your gonna hear that.
Joined: Aug 2006
Posts: 12,805
Likes: 107
From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Re: 383 HSR with 4inch Dynatech Split flow
Thread Starter
Joined: Sep 2003
Posts: 25,895
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
update, redoing the exhaust. I'm gonna try the ultraflo by dynomax. I got the muffler yesterday and today i slipped it on and started the car up. Also fixed a vacuum leak so the idle is lower and more choppy now. not as loud too
but the ultraflo is definately abit quieter at idle. i didnt let it idle long for each muffler tested but i could definately tell the ultraflo is quieter than the split flow at idle. i gave abit of gas to the ultraflo and its back to being pretty loud, but hopefully the rest of the piping will tone that down as i only was running dumps at the end of the muffler for testing
I also ran open y pipe for comparison and it was much louder than either of the two mufflers so they do 'work'. its just that with any throttle, it gets loud quickly
but the ultraflo is definately abit quieter at idle. i didnt let it idle long for each muffler tested but i could definately tell the ultraflo is quieter than the split flow at idle. i gave abit of gas to the ultraflo and its back to being pretty loud, but hopefully the rest of the piping will tone that down as i only was running dumps at the end of the muffler for testing
I also ran open y pipe for comparison and it was much louder than either of the two mufflers so they do 'work'. its just that with any throttle, it gets loud quickly
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From: Cypress, California
Car: 1989 GTA
Engine: 369 TPI
Transmission: 4L60E
Axle/Gears: 3.70 Nine Bolt
Re: 383 HSR with 4inch Dynatech Split flow
Looks like you are getting the "bugs" out of the car. My car is pretty quiet just cruising around and going down the hiway. However when you give it the gas it does roar.
Thread Starter
Joined: Sep 2003
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
getting there.
going to the car show tomorrow to see about hoods and possible tires if they are there
going to the car show tomorrow to see about hoods and possible tires if they are there Supreme Member
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From: p'cola FL
Car: 88 iroc-z/28
Engine: 408 lsx
Transmission: 5800 stall
Axle/Gears: 4.71
Re: 383 HSR with 4inch Dynatech Split flow
which ultraflo model did you go with?
ive got a stock replacement crossflow model. quiet as a kitten.
now going down the interstate at 4200 rpms is a different story.
cruising, idling, its as quiet as you can get, and flows better than any muffler out there.
ive got a stock replacement crossflow model. quiet as a kitten.
now going down the interstate at 4200 rpms is a different story.
cruising, idling, its as quiet as you can get, and flows better than any muffler out there.
Thread Starter
Joined: Sep 2003
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
its the 4inch in/out, 6" round case. 22 inches long i think it is
its alittle longer than the split flow but the main thing is that the ultraflo has larger holes on the inside of its glass wrapped tube core. that helps it be abit more quiet i think
its alittle longer than the split flow but the main thing is that the ultraflo has larger holes on the inside of its glass wrapped tube core. that helps it be abit more quiet i think
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From: Michigan
Car: 1984 Camaro Berlinetta
Engine: 355
Transmission: Th-350
Axle/Gears: 3.23
Re: 383 HSR with 4inch Dynatech Split flow
Get those pipes out behind the back bumper a little, guaranteed to help hush it up a little.
Oh yeah sweet engine build to.
Oh yeah sweet engine build to.
Last edited by stroker_SS; Jun 21, 2008 at 11:37 AM. Reason: i forgetted somthin"
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Joined: May 2001
Posts: 2,009
Likes: 5
From: Pitman, NJ
Car: '89 IROC-Z
Engine: Canfield 195 headed 358ci
Transmission: TH350, Art Carr 9.5"
Axle/Gears: 3.92 Dana 44
Re: 383 HSR with 4inch Dynatech Split flow
sounds good... what kinda fuel are you running with such a high CR and smallish cam? your DCR must be through the roof.
Thread Starter
Joined: Sep 2003
Posts: 25,895
Likes: 429
From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
93 octane. DCR is 8.3 to 1. STR is 11 to 1. Cam is small on the intake but its got loads of lift so its gonna act abit bigger than specs show. its 286 advertised on intake when most 230 cams are 280-282
On my break in runs so far i have seen no knock retard and no counts so far. timing is fairly conservative i think but i havent really loaded the motor up yet
On my break in runs so far i have seen no knock retard and no counts so far. timing is fairly conservative i think but i havent really loaded the motor up yet
Thread Starter
Joined: Sep 2003
Posts: 25,895
Likes: 429
From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: 383 HSR with 4inch Dynatech Split flow
took the car out today, the exhaust has been redone with the ultraflo muffler in place of the split flow.
Sounds abit quieter for sure at idle and part throttle. Stilll a touch louder than i wanted but much better than the split flow.
Sound at near WOT is the same. harder acceleration runs have about the same volume/tone so thats good.
Interior resonance has improved, its definately not as loud on the inside but still louder than i'd like. At cruise its fine, but on the throttle at 1400-2500 its loud inside the car with the windows down
Clearance improved but still hangs low. I tucked the rear up more and its given me some more cleance but the ultraflo has a fatter case at more like 7inchs instead of 5 of the split flow, so what i gained was partially lost by the fatter case. Still decent enough for me.
Idle is still abit erratic but abit better than before. its a touch lower, hovering between 875-1050 for the most part, desired is 950 then 900 after 176 degree coolant temps
May go work on the tail pipes now to get the tone exiting towards the rear of the car instead of over the axle.




The front end sits low since its on 25.4 inch skinnies. You can see about 1 inch to about 1.25 inch gap in fender from tire top. Once i get the new wheels/tires on, it should sit up another 1/2-5/8 inch atleast.
Rear is same way, its about 1.5-2 inch gap and is a 26.2 inch tire. new wheels/tires may sit 1/2 inch higher as well
Sounds abit quieter for sure at idle and part throttle. Stilll a touch louder than i wanted but much better than the split flow.
Sound at near WOT is the same. harder acceleration runs have about the same volume/tone so thats good.
Interior resonance has improved, its definately not as loud on the inside but still louder than i'd like. At cruise its fine, but on the throttle at 1400-2500 its loud inside the car with the windows down
Clearance improved but still hangs low. I tucked the rear up more and its given me some more cleance but the ultraflo has a fatter case at more like 7inchs instead of 5 of the split flow, so what i gained was partially lost by the fatter case. Still decent enough for me.
Idle is still abit erratic but abit better than before. its a touch lower, hovering between 875-1050 for the most part, desired is 950 then 900 after 176 degree coolant temps
May go work on the tail pipes now to get the tone exiting towards the rear of the car instead of over the axle.
The front end sits low since its on 25.4 inch skinnies. You can see about 1 inch to about 1.25 inch gap in fender from tire top. Once i get the new wheels/tires on, it should sit up another 1/2-5/8 inch atleast.
Rear is same way, its about 1.5-2 inch gap and is a 26.2 inch tire. new wheels/tires may sit 1/2 inch higher as well








, for some reason i looked at your pics and didnt see it, now i do, huh, guess i need more sleep