418ci LS3 dyno low??
418ci LS3 dyno low?? (Sigh) I know its very easy to get caught up in the numbers game. I try not to but seeing builds on all the searches ive done over the past few months and comparing them to mine, I expected something similar. Maybe that's where I went wrong? Anyway here is the build from a hydrolock 11 months ago. I spend my time on Corvette Forum but figured id post here to get even more input. Here is the build
Well first I must say I am stoked and really shocked about the torque curve and power at 2500rpm being over 400tq+
(good ole 243's). But I would be lying if I said I wasn't disappointed in the hp. Espically for a 418ci. My tuner did point something out and made realize that cats I still have on the car could very well be damaged and clogged. Especially since the reason the motor got replaced in the first place was due to hydrolock. Sooo called LG and have delete pips coming next week. I know my 1 3/4's are somewhat restrictive as well. Under cammed perhaps??? Any words??? build...
TSP 418
Weisco -4cc pistons
4.080 bore
Callies 6.125 rods
Callies 4.000 crank
Cometic .051 gaskets
11:3.1 CR
EPS Custom 240/248 .630 .603 116lsa
LS7 Lifters
Trunion Upgraded rockers
42lb injectors
Elite Engineering Catch can
SDPC blue printed oil pump
FAST 92 (not ported)
LS2 90mm TB (not ported)
TEA 243's Stage 2s
1 3/4 LG Street headers
Halltech Venom Intake
SLP UD Pulley
Corsa Xtreme's
Well first I must say I am stoked and really shocked about the torque curve and power at 2500rpm being over 400tq+
(good ole 243's). But I would be lying if I said I wasn't disappointed in the hp. Espically for a 418ci. My tuner did point something out and made realize that cats I still have on the car could very well be damaged and clogged. Especially since the reason the motor got replaced in the first place was due to hydrolock. Sooo called LG and have delete pips coming next week. I know my 1 3/4's are somewhat restrictive as well. Under cammed perhaps??? Any words??? build...TSP 418
Weisco -4cc pistons
4.080 bore
Callies 6.125 rods
Callies 4.000 crank
Cometic .051 gaskets
11:3.1 CR
EPS Custom 240/248 .630 .603 116lsa
LS7 Lifters
Trunion Upgraded rockers
42lb injectors
Elite Engineering Catch can
SDPC blue printed oil pump
FAST 92 (not ported)
LS2 90mm TB (not ported)
TEA 243's Stage 2s
1 3/4 LG Street headers
Halltech Venom Intake
SLP UD Pulley
Corsa Xtreme's
Last edited by SStheBest; Apr 18, 2015 at 02:21 PM.
Don't mind my sig. That was the LS6 (RIP)
I do believe the cats can be holding a little bit back considering they are 4+ years old then became water logged, sat for 10months, and are now running on the new motor. Not wise I know. Simply forgot. This was not a max effort build obviously. In fact it was originally planned to have a LS6 top end but a short notice deployment netted me the FAST 92 and TB. A 418ci 6sp should at least lay down 500. The car does pull like a freight train though!!!
I do believe the cats can be holding a little bit back considering they are 4+ years old then became water logged, sat for 10months, and are now running on the new motor. Not wise I know. Simply forgot. This was not a max effort build obviously. In fact it was originally planned to have a LS6 top end but a short notice deployment netted me the FAST 92 and TB. A 418ci 6sp should at least lay down 500. The car does pull like a freight train though!!! Last edited by SStheBest; Apr 17, 2015 at 10:08 PM.
TECH Junkie
Joined: Dec 2005
Posts: 3,092
Likes: 11
I would change out the catalytic converters and re-dyno. They very well could be the biggest problem. I see you have 1 3/4" headers, what is size of the rest of the exhaust system? This is an M6 transmission I take it.
Cat delete and ported fast is probably worth 30whp...probably another 10-15 going to a 1 7/8. There is a bit left in that combination if you wish to pursue it. However if you are happy and it runs good, then that is all that matters...dyno numbers are just that...numbers.
That's the plan. Corsa extreme is a 2.5" system. I have the 3.5" tips and LG's offroad mid pipe that come from a 3" merge but downsize to 2.5" mid/xpipe. So the system is a bit restrictive for a 418 once looking it over. However im certain those cats are a problem....
Cat delete and ported fast is probably worth 30whp...probably another 10-15 going to a 1 7/8. There is a bit left in that combination if you wish to pursue it. However if you are happy and it runs good, then that is all that matters...dyno numbers are just that...numbers.
Thanks!!!
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It really is not that bad. My 412 with All Pro Cathedral port heads made 511/489 through cats (we tested with and with out and it only made 6 rwhp difference) and 1 7/8 Kooks. I think freeing up the exhaust will gain on the top end, but will lose that torque you have down at 3000rpm, it is better than I had. If I were you, I would just do the ported intake and check the cats.
That low end torque is something you want to keep on a heavy street car.
That low end torque is something you want to keep on a heavy street car.
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Verdad Gallardo It really is not that bad. My 412 with All Pro Cathedral port heads made 511/489 through cats (we tested with and with out and it only made 6 rwhp difference) and 1 7/8 Kooks. I think freeing up the exhaust will gain on the top end, but will lose that torque you have down at 3000rpm, it is better than I had. If I were you, I would just do the ported intake and check the cats.
That low end torque is something you want to keep on a heavy street car.
That low end torque is something you want to keep on a heavy street car.
Honestly, this was supposed to be a budget build. Yes a set of LS3 heads can be had for cheap, but you must replace everything else to make them work. ie rockers, intake, rails, different injectors. Keeping my 243's and sending them to TEA was the cheaper route.
sending them to TEA was the cheaper route.
You could have sold your heads for $400, FAST for $700, injectors for $200, rockers for $100 then spent $600 on LS3s, ported them for $1200, $100 on new rockers, $150 on new injectors and $250 on a new intake. That would total $900 out of pocket.
So you could have saved 600 bux going the ported LS3 way. No idea how you think your way was cheaper, but that's kinda a moot point now.
You spent what like $1500 on the TEA porting?
You could have sold your heads for $400, FAST for $700, injectors for $200, rockers for $100 then spent $600 on LS3s, ported them for $1200, $100 on new rockers, $150 on new injectors and $250 on a new intake. That would total $900 out of pocket.
So you could have saved 600 bux going the ported LS3 way. No idea how you think your way was cheaper, but that's kinda a moot point now.
You could have sold your heads for $400, FAST for $700, injectors for $200, rockers for $100 then spent $600 on LS3s, ported them for $1200, $100 on new rockers, $150 on new injectors and $250 on a new intake. That would total $900 out of pocket.
So you could have saved 600 bux going the ported LS3 way. No idea how you think your way was cheaper, but that's kinda a moot point now.
Last edited by SStheBest; Apr 18, 2015 at 09:07 AM.
500hp isn't uncommon with the 243's. Since they are there, I will need to open it up else where.
Yes you have some other areas to open up and free more power, but you're really being limited by the heads. Those are good for torque down low, as you obviously have seen, but you can't expect ridiculous amounts of power up top...it's just the nature of the beast.
No it's not you're right, but stock cubed LS3s with stock heads and intake are pushing 500rwhp.
Yes you have some other areas to open up and free more power, but you're really being limited by the heads. Those are good for torque down low, as you obviously have seen, but you can't expect ridiculous amounts of power up top...it's just the nature of the beast.
Yes you have some other areas to open up and free more power, but you're really being limited by the heads. Those are good for torque down low, as you obviously have seen, but you can't expect ridiculous amounts of power up top...it's just the nature of the beast.
. I never was expecting 520+ with these heads. I knew it would be close to 500, just was hoping for a tad more. And honestly, looking at it, loosing the cats and if I decide to port match the FAST, there isn't a reason I wouldn't be spot on. Woulda already had it if I had the 1 7/8's. Lol if I had the money then I woulda gone with Trick flow's. 
TECH Enthusiast
Joined: Dec 2012
Posts: 563
Likes: 3
From: Wilson n.c.
its plenty of builds up here 416-418 with 243 heads making 500-550 rwhp so heads are not the problem.my build is going to be very close to this one.on a 408 tea has made 618 flywheel hp with 243s
TECH Fanatic
Joined: Aug 2009
Posts: 1,845
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From: Coast of San Mateo County Between Pacifica & HMB
As mentioned already
Ported (not port matched) Fast +10-12
ARH 1 7/8" + 8-10
cat delete 4-6 (if plugged)
Cam is at least 4-6* small both I&E to Peak 6200RPM+ with
418" and those Heads, IMO.
That said, your curve looks smooth, and the throttle-response
and Driveability are instantaneous and incredible I am sure.
Enjoy your car and upgrade down the road.
Otherwise this obsession can consume us.
Ask me how I know LOL!
Ported (not port matched) Fast +10-12
ARH 1 7/8" + 8-10
cat delete 4-6 (if plugged)
Cam is at least 4-6* small both I&E to Peak 6200RPM+ with
418" and those Heads, IMO.
That said, your curve looks smooth, and the throttle-response
and Driveability are instantaneous and incredible I am sure.
Enjoy your car and upgrade down the road.
Otherwise this obsession can consume us.
Ask me how I know LOL!
As mentioned already
Ported (not port matched) Fast +10-12
ARH 1 7/8" + 8-10
cat delete 4-6 (if plugged)
Cam is at least 4-6* small both I&E to Peak 6200RPM+ with
418" and those Heads, IMO.
That said, your curve looks smooth, and the throttle-response
and Driveability are instantaneous and incredible I am sure.
Enjoy your car and upgrade down the road.
Otherwise this obsession can consume us.
Ask me how I know LOL!
Ported (not port matched) Fast +10-12
ARH 1 7/8" + 8-10
cat delete 4-6 (if plugged)
Cam is at least 4-6* small both I&E to Peak 6200RPM+ with
418" and those Heads, IMO.
That said, your curve looks smooth, and the throttle-response
and Driveability are instantaneous and incredible I am sure.
Enjoy your car and upgrade down the road.
Otherwise this obsession can consume us.
Ask me how I know LOL!
You spent what like $1500 on the TEA porting?
You could have sold your heads for $400, FAST for $700, injectors for $200, rockers for $100 then spent $600 on LS3s, ported them for $1200, $100 on new rockers, $150 on new injectors and $250 on a new intake. That would total $900 out of pocket.
So you could have saved 600 bux going the ported LS3 way. No idea how you think your way was cheaper, but that's kinda a moot point now.
You could have sold your heads for $400, FAST for $700, injectors for $200, rockers for $100 then spent $600 on LS3s, ported them for $1200, $100 on new rockers, $150 on new injectors and $250 on a new intake. That would total $900 out of pocket.
So you could have saved 600 bux going the ported LS3 way. No idea how you think your way was cheaper, but that's kinda a moot point now.
throttle cable bracket $30
Valve spring kit $300 (assuming springs not included in your 1200 dollar porting figure?)
MAP extension harness $25
Fuel Rail $100
I'm not disagreeing with you...I'm in the middle of a cathedral to LS3 topend swap right now and just making the list more complete
I assume 1500 for TEA included springs?