Those of you with LS1 240Z's

[misturmoneybags]

I have a '73 240Z with a 305 SBC and I've been playing around with the idea of replacing the old 305 with an LS1. I've been researching and looking around for info about the swap for awhile, but I just want to hear from those of you driving LS1 Z's. My question to you is: when doing the swap, did you run into any nightmares? Or anything more difficult than usual. ALSO, I would like to hear all the good things about running with the LS engine.

 

I already know some of you may categorize MONEY into being a nightmare, but I'm well aware of the cost that accompanies the swap and I am prepared to eat spam and bread for awhile

[heavy85]

ALSO, I would like to hear all the good things about running with the LS engine.

 

Do it Do it Do it. Fast and scary fast are two good reasons for LS swap. It will be one of the most popular car at any race if you like attention. Is sounds good. It confuses people. It's fast. It uses stock parts so easy to work on. Decent mileage. It's fast.

 

In fact I can't think of a reason not too do it and would swap an LS again in a heartbeat. Only problem I had (actually have 'cause I never fixed it) was the fuel pump would only run for random amounts of time if controlled by the ECM. I hard wired the fuel pump around the ECM and it works fine. I used mostly stock Camaro parts and it worked out very well and stayed on budget.

 

Cameron

[ColtGT4g63]

Mine starts every time, every day, and never hesitates, drives perfectly smooth with out ANY hicups. gets excellent fuel economy on the freeway, and never lacks the power to get out of its own way, Even in 6th gear.

[misturmoneybags]

Thanks for you replies, guys! I'm definitely feeling good about the LS engine, but as far as dropping the engine and transmission into the car, are there any big jobs to be done? Perhaps fabrication wise?

 

And for you California residing guys, do you know of any shops or certain people that are capable of doing the swap? Because I definitely can't do this job myself, and I want the car to stay as my daily driver, so I need the swap do be done 100%.

[Cable]

....gets excellent fuel economy on the freeway

 

What kind of mpg are you avg?

 

Thanks!!

[1 tuff z]

i get about 30 on the highway traveling ~73mph on 87 octane pump gas. i have just over 12k on my swap now. have driven the z from rochester, ny to both mid ohio and daytona race tracks [then run the tracks while there for z conventions] and back with zero issues, sans a flat tire. running the q45 diff, 3.54 ratio. get 9mph when i'm running on the track [watkins glen intl].

[Savage42]

You running 87 octane? Can't imagine that's the best for performance or the long term of the engine. I often find myself thinking about using anything less than premium, as it's worth the $2-3 a tank to have the good stuff in there! Just my 2 cents. (Don't think my LS6 would be happy with 87, either)

[1 tuff z]

i normally run 93 only when i'm at the track otherwise it's 87. i don't race or drive it hard on the street-more of a "commuter z". i've run it that way since the swap [12k+ miles now] and seems to run just fine.

[ColtGT4g63]

What kind of mpg are you avg?

 

Thanks!!

 

 

i get about 30 on the highway traveling ~73mph

 

What he said.

[Cable]

What he said.

 

Cool, thanks.

[Savage42]

i normally run 93 only when i'm at the track otherwise it's 87. i don't race or drive it hard on the street-more of a "commuter z". i've run it that way since the swap [12k+ miles now] and seems to run just fine.

 

Well, I kinda hear ya! I'm of the mindset that I always want 100% performance available at all times.......just in case. It's like these Honda guys who have monster HP at 25 psi of boost and race fuel, but the real question is what they have right after they pull out from the gas station and want to play.

 

(Disclaimer: I am in no way promoting any racing on the streets, but only on a closed circuit under controlled circumstances!)

[Cable]

My LQ4 has 9.5:1 compression from the factory. 87 octane is all it needs. Putting 91+ octane gas is money going out the tailpipe and isn't helping make any more power either.

 

The higher the octane, the slower the gas burns. So you only need to run the min amount of octane your engine can handle without pre-ignition @ WOT, otherwise you are actually making less power (and spending more money) than you would if you were running the correct octane rating for your engine.

[Savage42]

With all things being equal, I would agree, but that is a generalization. That would mean that if 87 works for 9.5:1 and lower, 10:1 & 10.5:1 would require 89 and 91, respectively. (which is probably a good rule of thumb) If you live where it's hot, have a larger cam & headers, etc all require more octane. There is often a difference in static compression ratio & actual CR. Of course, we all know that everyone on Hydbridz is about "stock" motors, right?

 

"Many factors significantly increase an engine's octane requirement. They include a higher compression ratio, a bigger cylinder bore, leaner mixtures, higher coolant and intake-air temperatures, dry air (low humidity), higher barometric pressures, altitude closer to sea level, and more spark advance. Also, cast-iron heads need more octane than aluminum heads."

 

Here's some good info:

 

http://www.osbornauto.com/racing/dragster.htm

[Cable]

Allow me to clarify Gary, I wasn't meaning everyone needs 'only' 87 octane, I was just using my motor as a example.

 

Oil companies have spent tons of money getting folks into believing the "higher the octane the better" in terms of performance, engine wear, etc, etc regardless of the any factors related to the actual engine, car, performance, etc. Unfortunately it has worked because I know lots people who run 91 octane (highest found in Cali) in there mini-vans, Kia's, etc without any rhyme or reason other than they have the belief in the their mind that its "required" or its the "best for my motor".

 

These days most car companies list the octane that should be used in the owner's manual. Example: My 2007 Dodge HEMI Charger R/T's owners manual stated that 87 is all that is needed (unless towing, then use 89) and actually discouraged the use of anything higher than 89 octane all together.

 

Anyway, my original point is the same: You only need to run the min amount of octane your engine can handle without pre-ignition @ WOT, otherwise you are actually making less power (and spending more money) than you would if you were running the correct octane rating for your engine.

 

Of course everyone's octane requirement is going to be different, especially with various mods, weight, outside temp, tuning, etc. Even the age/mileage of the engine and the amount of carbon in the chambers could warrant different octane requirements. As such, some engines min octane requirements will be lower/higher than others.

[Savage42]

To get 100% optimization, you are correct. Problem is that there are so many variables and if the car is fairly loud, there can be detonation that can't be heard. So, as a cheap safety factor, it doesn't hurt to go with a higher octane to make sure you don't detonate and you won't see any significant drop in power by running premium. I really wonder if it would show much of a loss on a dyno. I can't run anything less than 91, but since you can run 87, maybe a dyno day with different fuel to test the theory is in order?

[rsicard]

Savage42: Suggest you go research all the articles that David Vizard has written to get a better insight into internal combustion engines. I run 87 octane in a 1994 Chev Suburban 3/4 ton with a rebuilt BIG BLOCK 454 stroked 1/4" and bored .030" for 489 Cu In and Edelbrock Aluminum Heads with 8cc less chamber for 9.1:1 and it is NOT ANYWHERE NEAR knocking. Pistons, Heads, valves and ports coated with ceramic. And I live in Tucson Arizona where the temp gets VERY HIGH and still NO KNOCK! Go figure.

[Savage42]

That just verifies everything we've been talking about! With a 9:1 motor, there is never a need to run high octane. If a motor is marginal on 87 and it gets hot, then higher octane is needed. Not the case is a low CR motor like yours. In the last 20 years, I've always run motors with 10.5:1 CR, which requires premium only, but also delivers more power and better mileage than a low compression motor. Still comes down to what people want and are willing to pay for performance.

[Cable]

To get 100% optimization, you are correct. Problem is that there are so many variables and if the car is fairly loud, there can be detonation that can't be heard. So, as a cheap safety factor, it doesn't hurt to go with a higher octane to make sure you don't detonate and you won't see any significant drop in power by running premium. I really wonder if it would show much of a loss on a dyno. I can't run anything less than 91, but since you can run 87, maybe a dyno day with different fuel to test the theory is in order?

 

True, our human ears may not detect engine knock, but our late model EFI PCM's (like our LSx powered S30's) will still detect engine knock even if the motor is as loud as a nuclear blast. A simple scanner will allow anyone to see if the PCM is applying any knock retard as a result of pre-ignition while driving, etc.

 

I will also agree that higher octane than needed will not cause any harm to the motor and can be a safety net, especially with a forced induction motor where you never know when or if the motor might go lean.

 

As far as significant power loss with higher octane, well there are a few factors involved with that. On a stock motor, I'll agree. However, a finely build n/a motor that operates in the 90%+ VE range will suffer with too much octane, I've seen as much as 20 HP on a 350 HP motor. Is that significant to everyone? Prob not, but it would be to me especially in my light S30 since 20 HP can easily be a 10th in the quarter. Am I alittle anal? Prob alittle.

 

My LSx powered Z isn't running yet but I have looked into dyno'ing with higher octane fuels, but I seriously doubt I'll gain much even if I advance the timing. Now if I had 11:1 compression (static) LSx, you bet all I'd run is 91+ octane regardless of what my dynamic compression is because I'll wouldn't be running a huge enough cam to bleeding off enough dynamic compression to risk going lower than 91.

[Savage42]

I know that there isn't anyone on this forum that has the "More is better" mentality, but there is a little room for motto to be incorrect when it comes octane needed. I guess we all just need max compression & HP, so we have to run Premium!

[Cable]

I guess we all just need max compression & HP, so we have to run Premium!

 

That'll work.