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3800 vs V8 ??? by Corpsmen Ed
Started on: 07-08-2013 02:51 PM
Replies: 85 (2581 views)
Last post by: chetw77cruiser on 05-12-2014 08:56 PM
fieroguru
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Report this Post05-12-2014 11:40 AM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by dobey:


Well a carbed first gen SBC is probably going to be as bad as people think for MPG. It's a very different engine from a modern LSx engine, which is also a bit different from a Northstar, Caddy 4.9, or an Audi V8. Comparing one specific V6 engine (3800) to a whole class of widely varied engines, based on one or two numbers, is just silly in itself.

It's too bad GM doesn't offer a small displacement V8 based on a mix between the LSx and their Indy Car engine, in anything. A 3.2L turbo V8 that turns 10K RPM would be pretty wicked in a Fiero.


I ran the same SBC with Carb and Fuel Injected and as a carb it would get 19 mpg on the interstate, with fuel injection it would get 22-23. In town the difference became even higher.

There is the 4.8L V8, but unfortunately it only came with a cast iron block. You could swap cranks and rods with the LS4 and destroke it to be a 4.8L as well.

GM is bringing back the 90 degeee 4.3L V6 with direct injection using the Gen V LT technology... I would love to swap one of those for a spirited daily driver.
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dobey
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Report this Post05-12-2014 01:07 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fieroguru:
There is the 4.8L V8, but unfortunately it only came with a cast iron block. You could swap cranks and rods with the LS4 and destroke it to be a 4.8L as well.


Swapping that crank and rods is exactly what I'm going to do with my LS4 build (if I can ever get the time/space to work on it). I've got a 4.8 short block sitting in my garage waiting for me to pull apart and get the crank machined to match the LS4 dimensions on the snout and flange.
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zzzhuh
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Report this Post05-12-2014 05:54 PM Click Here to See the Profile for zzzhuhSend a Private Message to zzzhuhEdit/Delete MessageReply w/QuoteDirect Link to This Post
Everyone that has mentioned the 4.9L swap seems to not fully understand these engines.

I actually own a 1991 Cadillac Seville with this engine in it. The fuel economy in it isn't amazing, usually getting around 15-18MPG in the city. My car does have 194,000 miles on it but at the same time it's been HELL to make it run the right way. As far as price it seems to be right around the same as a 3.8SC swap.

From the sound of it, it seems like a 3.8SC swap is out of the question for you because it's hard to find in your area.

I would definitely look into just doing a 3.4PR engine, mainly because of the cost but they are really easy to swap, and you'll have enough money left over to bore the engine, turbo or supercharge if you wanted to. The output won't be neck breaking but it will add a good amount of horsepower for the cost.

But in the end, it's all up to you.

------------------
The wetter the better

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Report this Post05-12-2014 08:00 PM Click Here to See the Profile for BZAnathemaClick Here to Email BZAnathemaSend a Private Message to BZAnathemaEdit/Delete MessageReply w/QuoteDirect Link to This Post
So I'm swapping my engine, trans, and ECU this summer regardless, and I was gonna go L67/4T60E. But you guys are really making me consider the 4.9. The problem is, I'm a perfectionist, and what attracts me to the L67 is the fact that I can yank the engine, transmission, and controller all from the same car or at least the same model and know it all works out. So noob questions:
What transmission should I pair with a 4.9 to have as little tuning to do as possible? I drive an auto - is that really an option for me? Can anyone toss some numbers on what your 4.9 cost? Where'd you pull the engine from?
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Report this Post05-12-2014 08:39 PM Click Here to See the Profile for hnthompsClick Here to Email hnthompsSend a Private Message to hnthompsEdit/Delete MessageReply w/QuoteDirect Link to This Post
Something to consider is the fact that the 4.9 V8 is around 200 HP but the 3800 SC is 240 for the Series II and 260 for the Series III. Performance options for the 4.9 appear to be limited but the 3800 SC can be modified to produce quite a lot of HP. My stock 3800 SC Series II engine (with a 3.4 pulley) dynoed at 258 HP and around 300 ft lbs of torque at the wheels. The Series III engine (N* tv, intercooler, 3.4 pulley, VS cam) dynoed at 300 ft lbs of torque and 300 HP at the wheels. Both of my tunes are conservative and I could easily produce more HP if I needed it.

Nelson
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chetw77cruiser
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Report this Post05-12-2014 08:56 PM Click Here to See the Profile for chetw77cruiserSend a Private Message to chetw77cruiserEdit/Delete MessageReply w/QuoteDirect Link to This Post
To each his own.

My choice is more of a logistics issue than a money issue. I am going with the 4.5/4.9 for my swap, not because they are "better", but due to the fact I have three sitting in the garage. I originally was going to use the 4.5 Allante, but trying to fin someone that can internally balance it in northern Colorado is proving difficult. I do drive in the mountains on a regular and the low end torque is useful and with the 4.5 I should still be able to spin it up some before navigating to the next higher gear. I am going to use a nvg-t550 (later getrag) for my swap as well as an aftermarket ecu, so I will have a better chance of good MPG and power vs stock tuning. I also have some other modifications planned that will make these engines a bit more lively, but I will save that for another day.

Now if I had the 3800SC available, I would have gone that route, but the V8's were practically free an too good to pass up.

The 3.8 an the 4.9 both can be swapped in with associated trans and ecu with relative ease. Some folks on the list may even be able to make a wiring harness to meet your needs as well program said ecu to match your swap. I like the idea of the 3.8 a bit more because of the auto that comes with it. The 4t65e is a bit more durable than the 4t60e and can be built to a higher standard if needed. Also as others have said, part are easier to find for the 3.8 vs the 4.9, especially the aftermarket if more power is your objective.

The way I look at it is any swap that is fairly easy and increases the fun factor is a good swap.

O.T. zzzhuh, where are you? I sent a message earlier. If you are in Collins, we need to meet up some time.
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