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Discussion Starter #1
1. Okay guys I really like the idea of 440rwhp through a 6 speed and a stock 10-bolt. I have my plan set out on how to achieve it, and now I would like to know how you guys would go about it. I would like it N/A, stock cubes, and it to be emisions legal?

2. Now how would you guys do this if, I used forced induction?(thought I'd make it a little easier for yah :D )
 

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N/A, Stock Cubes, and Emission Legal = A snowballs chance of surviving a summer vacation in hell. About the most power you're going to yank out of an emissions complaint setup is the 380 or so mark.

It CAN be done (not withstanding the emissions part), but it's going to be a BIG cam and a good set of heads.
 

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Another thing I want to add is how deep is your pocket?! To support that power your going to need a really good rotating assembly (light and strong!) for the power and for the high engine speeds you?ll be running and that?s lots of $$$. From my knowledge Chevy stated that the recommended max speed for that motor was 6200 rpm. On top of that you?re going to need to have a really good valve train (including great breathing heads) and a nice big cam!! O yah and your rear end, if you use a stock rear end with that much power (420 at the wheals) and put slicks on it you?ll go about 10 feet before that rear end snaps like a twig!! I mean it?s not impossible to get that much power!!! You just have to be realistic about the amount of money you will spend. If you got the money to spend build it!!!!!!!! And to make that car pass emissions I have no idea if it would pass!! But I am sure there is a way to make it happen!!

Check out this video it?s of a turbo Trans Am racing a twin turbo supra!!! It?s sweet!!
http://www.gtphorsepower.com/TTA-vs-supra.avi
 

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NA, 350cid, LTX, emissions legal, 440rwhp? very high compression, short duration race profile solid roller cam, very good cylinder heads (18 degree or tighter) and a very, very good tune.

Or just spray it...
 

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Discussion Starter #8
contraststriker said:
440 rwhp through a stock 10-bolt? You better hope you never get traction!
I don't plan on keeping the 10-bolt. I was just throwing that out there for informative purposes, because 440rwhp through a 9 inch is different.
 

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Discussion Starter #9
gettinthere said:
440 N/A to the wheels is real tough out of an LT1. Hell, most LS1 guys struggle to hit that.
Most LS1 guys I know are getting that goal, without to many troubles. I know one guy thats running some really good heads and a small cam, and another that has untouched heads and a T-rex cam, that did it to.

What if I go the LT4 route and get some ported LT4s or Ported AFRs LT4s?
 

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Enthusiast said:
Most LS1 guys I know are getting that goal, without to many troubles. I know one guy thats running some really good heads and a small cam, and another that has untouched heads and a T-rex cam, that did it to.

What if I go the LT4 route and get some ported LT4s or Ported AFRs LT4s?
the extra cost of an LT4 can be spent on an awesome set of LT1 heads and you'll see more gains. LT4s are completely overrated for the price.
 

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Enthusiast said:
Most LS1 guys I know are getting that goal, without to many troubles. I know one guy thats running some really good heads and a small cam, and another that has untouched heads and a T-rex cam, that did it to.

What if I go the LT4 route and get some ported LT4s or Ported AFRs LT4s?
You're comparing apples to steak there my friend. The LTx vs. LSx is night and day. You're talking about a typical SBC with a couple minor revisions (LT1) as compared to a completely new motor (LSx).

Even if you throw a set of AFR 215RR's, you're NOT going to get 440 RWHP and be emissions legal. The LTx series just required too big of a setup to make that power without sacrificing emissions passability. Period.
 

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Not on stock cubes anyway....a 396 with AFR LT4s would easily hit the hp # with the right cam, but you are right the emissions issue is the big variable.

Visual inspection is easy.....retain AIR, EGR, cats, etc even if EGR is off in the PCM.

If its OBDII emissions testing it can be made to pass. If its the sniffer its going to be alot more of a challenge but I think it could be done...but again, not on the stock bottom end.
 

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Enthusiast said:
Most LS1 guys I know are getting that goal, without to many troubles. I know one guy thats running some really good heads and a small cam, and another that has untouched heads and a T-rex cam, that did it to.

What if I go the LT4 route and get some ported LT4s or Ported AFRs LT4s?
Most H/C LS1's are putting down around 425-430ish.


I'd stay away from the LT4 route. There are much much better options out there for a fraction of the price.
 

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Discussion Starter #14
I want an emmisions legal car but I don't need one really. If it can't pass I'll just take in the truck for two inspections and steal one of the stickers. :D Also I heard OBDII they just hook it up to the computer and look for codes. If I had the car programmed and it was OBDII could they program it to where the computer would say it was emmisions compliant?

About the LT4s being too much. I was always told they where the far superior head untouched because the LT4s where made with knowledge gained from the LS1 project, and ported the advantage becomes even more apparent. I went to jegs and the LT1 185cc AFRs where ~2000 dollars and the LT4 195cc where ~1900. So the price difference wouldnt be too bad, I know I would have to get a new manifold and possibly other parts, but I could stomach the price if the LT4s are the superior part as Ive been told before.

About stroking it, I've been considering this and I'm doing some research on it and trying to see if its what I want. Sounds good to me though, I mean more cubes whats not to like? So what size would you guys go with, I know the 383 is a proven combo, Ive got one I built thats sitting in my garage right now, but I would also like the 396 for nostalgia purposes but I've heard its a PITA, so are those extra 13 ci worth the trouble. Also if I did an LT4 stroker I had been told the LT4 205cc (I think) are a good match to it. There operating RPM on a ,stock cube,LT1 is like 3500rpm to 6500rpm with more displacement, a la stroker, it would bring the operating speeds down some right? Thanks for all the help guys
 

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Discussion Starter #16
I was told that the LS1 project was already underway when the LT4 project was started.
 

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Enthusiast said:
I was told that the LS1 project was already underway when the LT4 project was started.
That's very true...but the LT4 head isn't an all new head...The LT4 wasn't an all new motor.....its just a hot-rodded LT1.

The LT4 took the lessons learned from the LS1 and applied them to the LT1 head to make it better....so the LT4 isn't better than the LS1 at all. The LT4 was still limited to the basic LT1 architecture. Its just bigger valves, & bigger ports basically.

The AFR LT4 heads are probably going to be the best flowing LT series heads out there right now, after they are ported. But they still won't flow much more than a ported stock LS1 head.

Now the STOCK LT4 heads from GM certainly outflow an LT1 head but are not even quite as good as a stock LS1 head...And as was said unless you're going to pay to have the LT4's ported, then don't waste your money as a ported LT1 head will outflow the stock LT4 head.
 

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Enthusiast said:
Ive got one I built thats sitting in my garage right now,
An LT1/LT4 or just a small block chevy? Because they aren't interchangeable. The blocks look the same but the optispark and gear driven water pump won't bolt to a regular small block.
 

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Discussion Starter #19
Chris 96 WS6 said:
That's very true...but the LT4 head isn't an all new head...The LT4 wasn't an all new motor.....its just a hot-rodded LT1.

The LT4 took the lessons learned from the LS1 and applied them to the LT1 head to make it better....so the LT4 isn't better than the LS1 at all. The LT4 was still limited to the basic LT1 architecture. Its just bigger valves, & bigger ports basically.

The AFR LT4 heads are probably going to be the best flowing LT series heads out there right now, after they are ported. But they still won't flow much more than a ported stock LS1 head.

Now the STOCK LT4 heads from GM certainly outflow an LT1 head but are not even quite as good as a stock LS1 head...And as was said unless you're going to pay to have the LT4's ported, then don't waste your money as a ported LT1 head will outflow the stock LT4 head.
I know the LS1 heads are far superior to the LT series heads. I'm just trying to think of a good way to squeeze a lot of horsepower out of an lt series engine. I have decided on going the LT4 route. It says an AFR head is already fully ported, so can they be ported more by say LE or AI? Ported GM LT4s or Ported AFR LT4s? What size heads 195cc or the 205cc? Would the 205ccs operating speed come down with more cubic inches?

Oh and its a SBC
 

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The AFR casting has more material to remove/port than the stock castings....which is why the AFR even exists. AFR's are known to be pretty rough out of the box, so you're not going to want to run them before having them cleaned up or more porting done.
 
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