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LT1 motors ... and then the LS, with a brake question at the end


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#1 SoCalTA

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Posted 11 April 2020 - 06:38 AM

Well guys .. 

with all the extra time, I've been looking at how to upgrade my car's performance, specifically the motor.  With that, I am curious about a few things and thought you guys are smarter than me on these sorts of topics .. so here goes:

 

 

 

What would it take to get an LT1 into the 600hp (at the tires) range NA and/or with an SC?  Sorry not looking into Nos.

What would you say is the max HP improvement with heads and cam, that the stock motor can take without any bottom end work?

Is there something about the LS motors that allow them to add heads and cam plus a SC without the need to upgrade the bottom end or am I missing something.

 

I have spent probably too much time watching videos but it just seems like the LS can take more upgrades, without the same kind of work needed by the LT1. Not saying its true... but only based on my observations.  Maybe there is another video that shows all the bottom end work in another video ... damn Youtube has me wondering ....

 

 

the last part relates to brakes ...

 

Can you guys suggest any lightweight calipers (front and back) that are larger/better than what came with the car?  I saw some AP racing in one video on a Mustand ... but also have seen some C7 and CTS-v brembo upgrades ...

 

thanks for enduring my questions..

 

be safe...

 

Jorge 



#2 Injuneer

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Posted 11 April 2020 - 08:22 AM

"600 hp (at the tires)" through your M6?  I'm assuming that the " M^ " in your profile is a typo.  Normally aspirated, you would be looking at 690 HP at the flywheel.  That would take a set of NASCAR SB2.2 racing heads.  I've seen dynos of 750+ HP at the flywheel with those heads.

 

Just curious... why did you pick "600 hp (at the tires)"?


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#3 SoCalTA

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Posted 11 April 2020 - 08:37 AM

Hey Fred ....

 

I was contemplating heads, cam and SC .. and its sort of based on some Corvette videos I have seen that have had heads/cam and/or supercharger.  which is the basis for some of the questions ... it "seems" that they can achieve those numbers with "relative" ease and so part of this is to juxtapose the motors and why one (LS) seems easier to get to a certain number than say and LT motor (ours)..  Are they just built more solid and so the power adders dont require more internal changes ... whereas the LT1's need a full rebuild..

 

I have read that our motors dont handle SC or turbos very well and also it seems that there is an upper threshold with heads and cam and not bottom end work... so in essence I want to see what it would take to get to those number - and why the LS motor seems to do so with relative ease .....

 

just trying to understand the nuances of these motors and what the upper limits are ... 



#4 Injuneer

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Posted 11 April 2020 - 08:57 AM

690 rwHP normally aspirated LT1 thread:

 

https://www.camaroz2...-dyno-s-529313/

 

There's really no practical limit what you can do with the LT1.  Current drag racing record on an LT1 factory block/M6 is 7.28 seconds @ 196 MPH.

 

As far as the difference between the LT1 and LS1 blocks - the cast iron LT1 block has 2-bolt mains (except LT1 engines used in the Corvette = straight 4-bolt mains).  The LS1 is an all aluminum block, with cast iron cylinder sleeves and deep skirt to allow 6-bolt mains.  4 vertical bolts in each main cap and a horizontal cross-bolt into both sides of each main cap.  The LT1 block just needs a a 4-bolt conversion (~$350).   Once you get into the 1,000+ HP range, some prefer to go to some degree of block fill.  But I've seen a stock straight 4-bolt LT1 block reliably make 1,125HP at the flywheel with no fill.  I have a Pro-Gram splayed 4-bolt conversion, but the shop that built the engine seemed to feel the LT1 block was designed based n the stronger GM Bowtie SBC and GM put the "meat" for the 4-bolt Corvette version in the correct location for straight bolts, not splayed.

 

Good writeup on the LS1:

 

http://netmotive.net...s/hib/ls1c.html

 

Note that you would not be able to use your current M6 trans with the LS1 engine - the LS1 input shaft is longer and the front plate on the trans case is different to accommodate in integral hydraulic slave cylinder for the LS1's conventional  "pusher" type clutch, as opposed to the LT1's "pullback" style.  You could have the trans rebuilt with the LS1 version input shaft and front plate, and you're going to have to have the trans upgraded no matter which engine you use.  The synchros and bearings are stressed over maybe 600 HP.



#5 Injuneer

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Posted 11 April 2020 - 09:17 AM

I have read that our motors dont handle SC or turbos very well and also it seems that there is an upper threshold with heads and cam and not bottom end work... so in essence I want to see what it would take to get to those number - and why the LS motor seems to do so with relative ease .....

 

 

Not sure where you're finding all this negative propaganda.  Forced induction probably true in excess of 1200HP range.  But Jonathan Atkins' record holding LT1 is turbocharged, and has actually been destroked to 329 cubic inches.  20 years ago the shop that built my engine was building 1,000+ HP supercharged LT1's.  Buddy of mine had one... I had the opportunity to drive it....it was insane at 1,125 flywheel HP, and street driven.  He held the LT1 record for two years back in 1999, but the 4,000 # 97 30th SS convertible was only running 9.05 @156 MPH.  Yes, above 500HP at the flywheel, 4-bolt mains are needed, while the LS1 already has them.

 

And, keep in mind, the LS1 heads have issues with lifting under high boost.  Not as many head bolts as the earlier SBC engines.  But there are "fixes", but they cost money.

 

I would agree the LS1 engine is the way to go if you are looking for outrageous HP.  But there is a cost associated with it.  If that is your preference, just buy a 99+ F-body and avoid all the conversion problems.

 

While my nitrous engine only makes 800 HP at the flywheel, it is totally useless on the street.  The best setup it ever had was 500 HP at the flywheel normally aspirated, a 125 HP first stage on nitrous that was somewhat usable on the street, and a 150 HP second stage which I could hit once it was up to a speed where traction was still possible.  But, in retrospect, the 500 HP NA setup was all that was really needed for a fun street driver.  It doesn't matter how fast your car is, there is always someone faster.



#6 SoCalTA

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Posted 11 April 2020 - 09:45 AM

thanks Fred .....

 

I read on a Camaro site that the stock motor cant handle boost/pressure and that the easiest way to grenade the motor was to do so....

 

I am wondering how much hp I can build with the stock bottom end and stock tranny while focusing on the top end. I'd be happy with 500 hp at the wheels ....



#7 Injuneer

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Posted 11 April 2020 - 11:39 AM

Then don’t use your LT1 if you want to use forced induction, and have no confidence in the LT1 engine.   That's about all I can say beyond what I have already posted.



#8 ZumpTA

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Posted 11 April 2020 - 12:15 PM

It's not a matter of adding boost, it's HOW MUCH boost.  Damn near every engine on the planet can handle 6psi on stock internals, some can even handle 10.  I have read from a lot of reliable sources that the LT1 was good to 600HP, and I have seen ragged out regular old SBC's with good compression make over 600HP boosted on stock internals and be a reliable dyno test platform for various top end/intake/carb setups  producing nearly 700 for years.  I couldn't imagine the LT1 being any weaker than it's predecessors.

 

...but why even bother with an LS or LT?  Blueprint has a 632ci pushing 800/800 NA and it's built for boost.  Go big or go home, right?  :)

 

Thinking more about it, the LT1 is begging to be boosted.  With the reverse flow cooling system not only is the top end cooled first which is a huge plus, the cylinder walls retain a more uniform diameter all the way through the stroke leading to less ring movement (expansion and contraction). 

 

There is a huge LS market out there, and Gen II LT1 guys are farther and fewer between these days, but, the LT1 is definitely a strong platform good for power AND durability.  If you're going for records, ya, there is better.  ...but simply Bad Ass? The LT1 can most certainly do that. 

 

I only know of one company that builds 500HP+ LT1's and offers a good warranty with them.  Golen Engine Service.  Maybe give them a call and see what their experience and recommendations are.  There may be other builders but they were the only ones offering high horsepower turn key engines with a strong month/mileage warranty.   Some day I hope to have them ship me something.


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#9 94formularebuild

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Posted 12 April 2020 - 02:33 PM

SoCal, what’s your goal? I went to an engine builder and asked if they could make a high hp engine, they asked me the same question. I didn’t want a high maintenance build and don’t plan on spending much time on a track or strip. They explained how an engine with higher torque makes a fun street machine since it is felt at lower rpms, where with an automatic ( what I have) it requires a high stall torque converter to realize the engine’s max hp and do you want to rev your engine up to 3000 rpm just to set you back in the seat? I have driven my friend’s 600 hp (at the flywheel) race car with an automatic ,96 Firebird lt1, and I understand what the engine shop was saying. My budget wouldn’t allow me to build the most powerful lt1 ever made, and even if I could, someone would build one bigger and better. I opted to have mine stroked and cammed to make it an enjoyable street car.

#10 SoCalTA

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Posted 12 April 2020 - 04:04 PM

thanks guys .. for all the information and questions.

I am not setting out to drag race .. nor really am I looking to do track days.  I have a 87 IROC thats a purpose built roadracer for that.  What I do want is something thats an improvement over the near stock car.  I know that there is always someone out there with more ... I just dont want to have a fast looking car .. thats slow.  Its more of a weekend hot-rod that I want to bring up to date .... thats the reasoning for the question on tires and wheels .... the stock 16's never appealed to me ..... I'd like to upgrade the brakes ... upgrade the motor and increase the smiles per hour as it were without adding more headaches down the road .....  

 

Honestly .. I dont know .. which is why I am soliciting perspectives and experiences ... I know I am not going to rebuild the motor from top to bottom ...  but I do feel like upgrading a few things will make it more fun ...






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