Generation IV Internal Engine 2005-2014 LS2 | LS3 | LS7 | L92 | LS9

408ci advice?

Thread Tools
 
Search this Thread
 
Old 12-04-2009, 02:45 AM
  #1  
Teching In
Thread Starter
iTrader: (23)
 
Outlaw E36's Avatar
 
Join Date: Aug 2007
Location: CA
Posts: 34
Likes: 0
Received 0 Likes on 0 Posts

Default 408ci advice?

So i have in mind of building a 408ci shortblock with a 12:1 compression and using pump gas so i could drive it on the weekends. A couple friends of mine told me the dome piston is a bad idea an so is a 12:1 with pump gas. I wanted to know what you guys thought of this set up and what advice you have to build a 12:1 with pump gas. If im not able to use 12:1 with pump gas i was thinking of just goin with a 13:1 n high octane weekend warrior

Wiseco +5cc dome pistons
.040" gasket
72cc heads
Old 12-04-2009, 02:50 AM
  #2  
TECH Fanatic
 
xdanny510x's Avatar
 
Join Date: Jun 2006
Location: Hayward CA
Posts: 1,326
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by Outlaw E36
So i have in mind of building a 408ci shortblock with a 12:1 compression and using pump gas so i could drive it on the weekends. A couple friends of mine told me the dome piston is a bad idea an so is a 12:1 with pump gas. I wanted to know what you guys thought of this set up and what advice you have to build a 12:1 with pump gas. If im not able to use 12:1 with pump gas i was thinking of just goin with a 13:1 n high octane weekend warrior

Wiseco +5cc dome pistons
.040" gasket
72cc heads
im running a pretty close set up to 12;1 .. mine is 11:8:1 compression using 91 octane my heads are 64cc-62cc i forgot with diamond dished pistons..First decide what u really want man..
Old 12-04-2009, 02:51 AM
  #3  
Banned
iTrader: (115)
 
99blancoSS's Avatar
 
Join Date: Feb 2005
Location: ST Helens, OR
Posts: 9,892
Likes: 0
Received 3 Likes on 2 Posts
Default

12:1 is not a good idea for pump gas ( typicaly 91-93 octane), 13:1 is a PIA to run race gas in a street car and do you know race fuel cost? I would re-think it. What are you trying to accomplish?
Old 12-04-2009, 03:02 AM
  #4  
Teching In
Thread Starter
iTrader: (23)
 
Outlaw E36's Avatar
 
Join Date: Aug 2007
Location: CA
Posts: 34
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by xdanny510x
im running a pretty close set up to 12;1 .. mine is 11:8:1 compression using 91 octane my heads are 64cc-62cc i forgot with diamond dished pistons..First decide what u really want man..
What kind of power did you make with that set up.?
Old 12-04-2009, 03:16 AM
  #5  
Teching In
Thread Starter
iTrader: (23)
 
Outlaw E36's Avatar
 
Join Date: Aug 2007
Location: CA
Posts: 34
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by 99blancoSS
12:1 is not a good idea for pump gas ( typicaly 91-93 octane), 13:1 is a PIA to run race gas in a street car and do you know race fuel cost? I would re-think it. What are you trying to accomplish?
Thats what i was told that it wasnt a good idea but i read a couple threads were people were using pump gas on a 12:1. My goal was to build a streetable race car (not a DD) with good power so I figure the best thing was a 12:1 compression.

The idea of 13:1 was only if I was to build a stright race car and not be able to drive to the mall or cruise it on the weekend

Last edited by Outlaw E36; 12-04-2009 at 03:37 AM.
Old 12-04-2009, 04:31 AM
  #6  
On The Tree
iTrader: (3)
 
spare tire's Avatar
 
Join Date: Jul 2006
Location: Sux City
Posts: 149
Likes: 0
Received 0 Likes on 0 Posts

Default

You can get by with 12:1 on 93, Just depends on what kind of cam you run. Based on what you are saying I would say set your sights a little lower. You can make good power with lower compression... It all depends on the combination.
Old 12-04-2009, 06:03 AM
  #7  
TECH Fanatic
 
xdanny510x's Avatar
 
Join Date: Jun 2006
Location: Hayward CA
Posts: 1,326
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by Outlaw E36
What kind of power did you make with that set up.?
Haven't took it to the dyno yet cause I have a shitty 4l60e and I'm afraid of breakin it on the dyno..but give or take Nick at newtech said around 480ish rwhp n/a and around 700-750 on bottle
Old 12-04-2009, 09:13 AM
  #8  
Teching In
Thread Starter
iTrader: (23)
 
Outlaw E36's Avatar
 
Join Date: Aug 2007
Location: CA
Posts: 34
Likes: 0
Received 0 Likes on 0 Posts

Default

thank for the replies so far guys.

Now what do you guys think of dome pistons and the set up
i posted above.?
Old 12-04-2009, 12:41 PM
  #9  
Banned
iTrader: (115)
 
99blancoSS's Avatar
 
Join Date: Feb 2005
Location: ST Helens, OR
Posts: 9,892
Likes: 0
Received 3 Likes on 2 Posts
Default

Originally Posted by spare tire
You can get by with 12:1 on 93, Just depends on what kind of cam you run. Based on what you are saying I would say set your sights a little lower. You can make good power with lower compression... It all depends on the combination.
Yea well you dont make more power by hanging the intake valve open to relieve compression and if your backing timing down your not making more power either.

Last edited by 99blancoSS; 12-04-2009 at 12:46 PM.
Old 12-04-2009, 12:45 PM
  #10  
Banned
iTrader: (115)
 
99blancoSS's Avatar
 
Join Date: Feb 2005
Location: ST Helens, OR
Posts: 9,892
Likes: 0
Received 3 Likes on 2 Posts
Default

Originally Posted by Outlaw E36
Thats what i was told that it wasnt a good idea but i read a couple threads were people were using pump gas on a 12:1. My goal was to build a streetable race car (not a DD) with good power so I figure the best thing was a 12:1 compression.

The idea of 13:1 was only if I was to build a stright race car and not be able to drive to the mall or cruise it on the weekend


Listen to the guys who said it's not a good idea. Hi compression is not a bragging right. 11:1 on 91 octane is what we recommned and HKE has some of the fastest N/A cars you will find. 9.4 seconds on 91 octane with a 3300 lb car.

Last edited by 99blancoSS; 12-04-2009 at 01:25 PM.
Old 12-04-2009, 03:27 PM
  #11  
TECH Fanatic
 
kumar75150's Avatar
 
Join Date: Mar 2003
Location: Dallas
Posts: 1,112
Likes: 0
Received 0 Likes on 0 Posts

Default

you could get away with it with a big enough cam and easy on the timing for street driving

i ran 11.8:1 on my 408
Old 12-04-2009, 04:25 PM
  #12  
Teching In
 
68_C10_408_stroker's Avatar
 
Join Date: Sep 2009
Posts: 3
Likes: 0
Received 0 Likes on 0 Posts

Default

Lower the compression and supercharge it if you want the best of both worlds. Then you can run 87-89 during the week, and 91-93 at the track. There will be plenty of power for you with that set-up.
Old 12-04-2009, 04:42 PM
  #13  
TECH Fanatic
iTrader: (2)
 
dutinsss's Avatar
 
Join Date: Sep 2007
Location: Cairo, GA
Posts: 1,235
Likes: 0
Received 0 Likes on 0 Posts
Default

as said, don't risk having to run race gas just to get a little more compression. keep it at a safe compression and use other parts to make the power your looking for.
Old 12-04-2009, 04:45 PM
  #14  
9 Second Club
iTrader: (23)
 
tektrans's Avatar
 
Join Date: Nov 2003
Posts: 3,377
Likes: 0
Received 0 Likes on 0 Posts

Default

My old 408 was 12:1. I raced it on 104 (really 105 my track doesn't have 104 so I had to mix 110 and 100) (1/2 and 1/2) but anyway, I did drive it on the street with pump gas all the time BUT BUT BUT, you cannot go WOT on the pump gas if it's tuned on the race.
If you go 13:1, you'll have to drive it on the race, maybe a race/pump mix but still can't go WOT unless you have full race gas in it. That's how I did it anyways. Now I have 13:1and drive it on the full 110 octane or a 110/93 mix. I can't go WOT on the street anyway, unless I want to kill myself.
Old 12-04-2009, 07:33 PM
  #15  
Teching In
Thread Starter
iTrader: (23)
 
Outlaw E36's Avatar
 
Join Date: Aug 2007
Location: CA
Posts: 34
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by 99blancoSS
Listen to the guys who said it's not a good idea. Hi compression is not a bragging right. 11:1 on 91 octane is what we recommned and HKE has some of the fastest N/A cars you will find. 9.4 seconds on 91 octane with a 3300 lb car.
I did some research on 11:1 and ive seen some people making some good
power. But how much power difference would it be from 11:1 to 12:1.?
Old 12-04-2009, 07:42 PM
  #16  
Teching In
Thread Starter
iTrader: (23)
 
Outlaw E36's Avatar
 
Join Date: Aug 2007
Location: CA
Posts: 34
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by kumar75150
you could get away with it with a big enough cam and easy on the timing for street driving

i ran 11.8:1 on my 408
What were the specs and what kind of power are you making.?

Originally Posted by 68_C10_408_stroker
Lower the compression and supercharge it if you want the best of both worlds. Then you can run 87-89 during the week, and 91-93 at the track. There will be plenty of power for you with that set-up.
I wish i had the money for a supercharger. For now im sticking to a 408
and nitrous

Originally Posted by tektrans
My old 408 was 12:1. I raced it on 104 (really 105 my track doesn't have 104 so I had to mix 110 and 100) (1/2 and 1/2) but anyway, I did drive it on the street with pump gas all the time BUT BUT BUT, you cannot go WOT on the pump gas if it's tuned on the race.
If you go 13:1, you'll have to drive it on the race, maybe a race/pump mix but still can't go WOT unless you have full race gas in it. That's how I did it anyways. Now I have 13:1and drive it on the full 110 octane or a 110/93 mix. I can't go WOT on the street anyway, unless I want to kill myself.
This is the type of set up i had in mind. I wasnt planning on racing it with pump gas cause im gonna be using nitrous, i just want to be able to cruise the car. What was the set up on your 408 and what kind of power did you make if you dont mind sharing or you can pm me.
Old 12-05-2009, 03:21 AM
  #17  
11 Second Club
iTrader: (4)
 
KCFormula's Avatar
 
Join Date: Nov 2002
Location: SoCal
Posts: 897
Likes: 0
Received 0 Likes on 0 Posts

Default

Really you should run flat top pistons and run a smaller chamber in your heads to help your quench.
Old 12-05-2009, 11:37 AM
  #18  
TECH Veteran
iTrader: (11)
 
87silverbullet's Avatar
 
Join Date: Mar 2007
Location: Slidell,LA
Posts: 4,873
Likes: 0
Received 8 Likes on 7 Posts

Default

Listen to 99blancoss. He will keep you pointed in the right direction. Keep it at 11.0 to 11.5. Spend the money on some good heads and a good cam.

Bumping the compression from 11.0 to 12.0 is not going to net you much power worth the cost of having to buy/find racefuel. You can run 11-11.5 and make the power you need.
Old 12-05-2009, 12:04 PM
  #19  
TECH Regular
iTrader: (20)
 
gmmusclecarman's Avatar
 
Join Date: Mar 2008
Location: Naperville, IL
Posts: 422
Likes: 0
Received 0 Likes on 0 Posts
Default

I run 11.38:1 CR on my 408 with 93 octane. I have TFS 235cc heads milled to 64cc and a custom cam(246/254). I put down 515rwhp with only a little bit of tuning and a shitty intake setup. Im hoping for 550 rwhp when its all said and done. Listen to 99blancoss he knows his ****

IMO there is no point in running that high of compression in a street car. Too expensive and too much of a pain to switch back and forth from pump to race gas.
Old 12-06-2009, 06:56 PM
  #20  
TECH Fanatic
 
kumar75150's Avatar
 
Join Date: Mar 2003
Location: Dallas
Posts: 1,112
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by Outlaw E36
What were the specs and what kind of power are you making.?
https://ls1tech.com/forums/dynamomet...o-results.html


Quick Reply: 408ci advice?



All times are GMT -5. The time now is 09:49 AM.