[Jhunsberger]

Fantastic #'s and build Ted, nice work as always!

[EDFHOBBIES]

Question Ted...

The power seems low compared to a LT4 engine that could run just a larger blower on 93 and make 720 at the wheels on 93..

I'm thinking that anyone that modifies a LT1 and has the money they should lower the compression? Maybe using the 65 cc lt4 vs the 59cc lt1?


seems like the higher compression is making the need for more octane is whats holding back some power..

I guess the reason ask is I was thinking of donation my heads to wifey she's getting my drop in pistons, Fuel pump, injectors and you smooth idle cam to along with her eforce 2300..

She all ready complaining that i'm faster now lol!

[JANNETTYRACING]

Originally Posted by VAZL1

Stock LT1 pistons?

Factory short block yes.

Originally Posted by Drsagacity

I assume that was a manual running 8psi?

9.5 per the dyno sheets.

Originally Posted by Murph18

Hopefully get mine in shop around March. Can't wait to see what this cam can do at the track.

Already installed
Maggie supercharger
Stainless Works 2" headers and full exhaust
Rotofab intake
85mm pulley

Ordered parts
Janetty supercharged rough idle cam
VR drop in pistons
Lt4 hpfp, injectors and zl1 in tank
Circle d converter
Dss driveshaft
80mm pulley

Going to stay on 93 for now.

Thank you for your business.

Ted.

[JANNETTYRACING]

Originally Posted by EDFHOBBIES

Question Ted...

The power seems low compared to a LT4 engine that could run just a larger blower on 93 and make 720 at the wheels on 93..

I'm thinking that anyone that modifies a LT1 and has the money they should lower the compression? Maybe using the 65 cc lt4 vs the 59cc lt1?


seems like the higher compression is making the need for more octane is whats holding back some power..

I guess the reason ask is I was thinking of donation my heads to wifey she's getting my drop in pistons, Fuel pump, injectors and you smooth idle cam to along with her eforce 2300..

She all ready complaining that i'm faster now lol!

An LT4 will not make 720 RWHP on 9.5 psi boost.

The LT1 is stronger per Lb of boost.

[EDFHOBBIES]

Of course the compression is almost 2 points higher.. I'm asking if a lower compression lt1 has the potential to make more power on 93 if the compression was lower vs the alternative of adding meth or e85.

Let's say the octane limit on 93 was 9.5 psi and I made 720 rwhp and that is near 11:1 but then I add LT4 heads and my compression drops to 9.5:1 now i make 800 15 psi on 93?

Correct or not i see that on the lt4's

The reason I ask is that I will have a set of LT4 heads off my car.. Do I stick them on hears or sale?

[JANNETTYRACING]

Originally Posted by EDFHOBBIES

Of course the compression is almost 2 points higher.. I'm asking if a lower compression lt1 has the potential to make more power on 93 if the compression was lower vs the alternative of adding meth or e85.

Let's say the octane limit on 93 was 9.5 psi and I made 720 rwhp and that is near 11:1 but then I add LT4 heads and my compression drops to 9.5:1 now i make 800 15 psi on 93?

Correct or not i see that on the lt4's

Without actually doing the combo and testing it all we are doing it theorizing.

It takes the same amount of cylinder pressure to make a certain power number whether you do it with high compression and low boost or low compression and high boost.

You will hit the octane limit either way.

Ted.

[laynlo15]

Thanks for explaining that.

[Drsagacity]

Originally Posted by EDFHOBBIES

Of course the compression is almost 2 points higher.. I'm asking if a lower compression lt1 has the potential to make more power on 93 if the compression was lower vs the alternative of adding meth or e85.

Let's say the octane limit on 93 was 9.5 psi and I made 720 rwhp and that is near 11:1 but then I add LT4 heads and my compression drops to 9.5:1 now i make 800 15 psi on 93?

Correct or not i see that on the lt4's

The reason I ask is that I will have a set of LT4 heads off my car.. Do I stick them on hears or sale?

That's an interesting take. I guess in theory lowering the compression ratio would reduce the likelihood of detonation and allows more air/oxygen and as a result, more power because higher boost levels are permitted (at the same static/effective compression ratio)?

That could also mean that when we add pistons, it would be a good idea to play with a lower compression piston or you are right, potentially swap heads to allow lower compression.

Wouldn't the tradeoff be heat? How fast can we spin the blower before we start seeing extra heat that will limit the performance benefit?

Originally Posted by JANNETTYRACING

Without actually doing the combo and testing it all we are doing it theorizing.

It takes the same amount of cylinder pressure to make a certain power number whether you do it with high compression and low boost or low compression and high boost.

You will hit the octane limit either way.

Ted.

Thanks Ted. That makes sense to me. I figured the real benefit to lower compression was simply to reduce the risk of blowing things up. It does make sense that you have to get to a given compression ratio in order to make a power number.

If that is the case, then it really comes down to reaching a given compression ratio AND reducing the likelihood of detonation, right? In that thinking, the lower compression ratio is beneficial because lower compression would mean less heat and less likelihood of detonation.


In other words, it would be interesting to see if lower compression and more boost would result in more power with the ability to run more timing without risking detonation. If anyone wants to donate a set of LT4 heads, I know of a guy that will be happy to test the theory.

[JANNETTYRACING]

I wish it was that simple but it is not.

Here's one for you in limited drag radial racing they are running 14:1 compression with 40-50 psi of boost.

[Drsagacity]

Originally Posted by JANNETTYRACING

I wish it was that simple but it is not.

Here's one for you in limited drag radial racing they are running 14:1 compression with 40-50 psi of boost.

Fair enough. I give up. How about this. I am going to stay with my setup and run it at the track to see what I can do. Then make decisions based on actual performance. It is fun to think about options and next steps, however.

[laynlo15]

Haha you are going to stay with what you have? Crazy

[EDFHOBBIES]

There is no way 40 or 50 psi on 93..lol race or c16 I believe

I'm just comparing seeing lt4 builds with aux pumps only and larger blowers making more power than a LT1 with same size blower and LT4 fuel parts.

Lt1s are around 650 where the lt4s 700s..

For instance bolt a whipple on a LT1 even with the lt4 fuel upgrades they make about 630 to 650..

Bolt the whipple on the LT4 and its 700 to 710

93 only, no cam upgrades....no meth.. not the same psi just where the octane limit is

[KingLT1]

That is because the LT4 is running more boost. Stock LT4 @ the stock 9psi makes around 550whp. A stock LT1 makes 550whp with 6-7psi.

[EDFHOBBIES]

Yes 6 or 7 psi is all you can do probably because compression is so high. The lt4 may be 9.4 lbs but the Maggie 2300 probably flows more so I'm not wrapped up in total boost its making, rather that which will make more hp on 93 only..

Yes.. boost is irrelevant though in my question and build watching generalizations ..I'm talking 93 octane limit and amount of HP that can be achieved on 93 octane with 11:1 or 9:1..

Take for instance this build 720 rwhp w cam and lt4 fuel parts. I've seen this combo make 800 on a lt4 w a cam.. different profile of cam but same fuel ystem...