Making the chevy 350 v8 more fuel efficient? - Page 2 - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #16 (permalink)  
Old 07-12-2007, 06:51 AM
Member
 
Last photo:
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 50
Posts: 4,021
Wiki Edits: 0

Thanks: 0
Thanked 23 Times in 23 Posts
K3,
I have a 350 power 240Z. Lots-o-fun. 11:1 cr, 362 cid, 292H compcam, 750 holley, 200cc dart heads with a T5 5spd and 3.90 gear. Runs 11.7's at 120 mph and 10.7's at 135 with 200 shot n02. Gets pretty good mpg on the highway but ever checked it. I was always to busy gripping the steering wheel and gnashing my teeth to worry about mpg.

go to hybridZ.com. lots of v8 Z information there.

I also have a home made 76 280 turbo Z. Runs very strong and will beat a lot of v8 powered Z's. Traps over 108mph in the 1/4 mile with the stock efi and a fmu for more fuel. Have you considered installing a turbo on your 240? It is much cheaper and much easier to do. There are a few crazy guys making over 500hp at the wheels with their in-line 6's over at hybridZ. 350-400 rwhp is common with bigger turbos and after market efi. Even the stock turbo and efi system is good for 275hp at the wheels.

It is possible to turbo charge your current 240 engine. Don't even need to pull it out. But the clutch will need to be upgraded to a 240mm. Check out the Z site. good luck.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #17 (permalink)  
Old 07-12-2007, 03:38 PM
DHMag's Avatar
Registered User
 
Last photo:
Join Date: Jun 2005
Location: InCahoots, Texas
Posts: 302
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
for once the tables are turned, junk the 350 and drop in a 305 !
Reply With Quote Quick reply to this message
  #18 (permalink)  
Old 07-12-2007, 04:09 PM
Registered User
 
Join Date: Jul 2007
Location: phoenix
Posts: 9
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Couple reasons i choose the v8 over turbo:
- Stock for stock the v8 makes more power (I really dont want to do much upgrades after the engine swap)
- I like the fact that with the crate v8 engines its new and hasnt been molested yet
- i like the sound of the v8 engine over a spool of a turbo
- the engine is a little more simplistic. and i friends that could help me with any problems regarding the chevy engines.

Ive read articles on getting high hp out of smaller displacement chevys (302 and 305), so im leaning more toward that route now.
Reply With Quote Quick reply to this message
  #19 (permalink)  
Old 07-13-2007, 07:13 AM
Member
 
Last photo:
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 50
Posts: 4,021
Wiki Edits: 0

Thanks: 0
Thanked 23 Times in 23 Posts
Sure, V8's are nice.

But, it is a lot tougher it get one into a Z than it looks. And it will cost twice as much as you budget for in both time and money.

I just got done helping a friend with a V8 conversion in a Z. Took a few months to get it back on the road and it still has a few issues that need to be fixed. Not an easy swap, I don't care what some people say.

A turbo 280 engine with 14 psi of boost will beat a moderately built 350 any day. FYI, 14.7 psi of boost doubles the output of an engine. This make a 2.8 liter into a 5.6 liter, or a 170hp L28 into a 340hp. Then add a little more boost and a little more cam for 400HP+.

In the JTR V8 conversion manual, a 240Z with a T5 5 speed trans with a stock 1978 350 (190hp) only ran 14.5 @ 96mph in the 1/4 mile. It took a 350hp alum head vette engine to get to a 107mph trap speed, my almost stock turbo engine does that. And with a better efi system and a little more boost, it can easily run 118mph in the 1/4 mile and idle like stock. Plus it is all simple bolt-on's.
Reply With Quote Quick reply to this message
  #20 (permalink)  
Old 07-13-2007, 07:20 AM
302 Z28's Avatar  
Last photo:
Join Date: May 2003
Location: North Texas
Posts: 10,837
Wiki Edits: 0

Thanks: 1
Thanked 86 Times in 73 Posts
Quote:
Originally Posted by 454C10
A turbo 280 engine with 14 psi of boost will beat a moderately built 350 any day. FYI, 14.7 psi of boost doubles the output of an engine. This make a 2.8 liter into a 5.6 liter, or a 170hp L28 into a 340hp. Then add a little more boost and a little more cam for 400HP+.
But, I'll wager my carbureted V8 will far outlive a turbo'd 280 engine. That turbo takes a toll on the engine after a time.

Vince
Reply With Quote Quick reply to this message
  #21 (permalink)  
Old 07-13-2007, 07:45 AM
Member
 
Last photo:
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 50
Posts: 4,021
Wiki Edits: 0

Thanks: 0
Thanked 23 Times in 23 Posts
In line 280z engines are very tough. Seven main bearings and forged cranks are the stock setup. The engine are so tough that nissan not only made factory turbo engines out of them, but they also made them into diesels. So the longs block can take a serious beating. I have seen pistons, cranks, and blocks reused with no machine work after 100K miles!

Plus it is very easy to add a turbo. The exhaust manifold, turbo, wastegate, downpipe, and J-pipe can be had easily at your local pick-n-pull junk yard. I bought a complete turbo engine for 150.00! Turbos with wastegates go for 40.00 and turbo exhaust manifolds go for 20.00.
Reply With Quote Quick reply to this message
  #22 (permalink)  
Old 07-13-2007, 11:52 AM
Registered User
 
Last wiki edit: How to title a hot rod Last photo:
Join Date: Feb 2007
Location: West Virginia
Age: 24
Posts: 3,389
Wiki Edits: 8

Thanks: 14
Thanked 1 Time in 1 Post
Quote:
Originally Posted by DHMag
for once the tables are turned, junk the 350 and drop in a 305 !
Not so sure about that one ............80 chevy 4x4 shortbed(2.76 gears?) with th350 and 350 -18mpg when new........1985 4x4 shortbed 3:08 gears with camaro 305 ho ported heads performer eps intake performer 1406 carb full length headers true dauls 700r4 trans........14ish
Reply With Quote Quick reply to this message
  #23 (permalink)  
Old 07-13-2007, 12:07 PM
Member
 
Last photo:
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 50
Posts: 4,021
Wiki Edits: 0

Thanks: 0
Thanked 23 Times in 23 Posts
My 454 gets 1 or 2 mpg more than my 396. And that is in the same truck using the same exhaust, trans, converter, rear end, carb, intake, ignition, cam, ect.

The 396 is my spare engine while I work on the 454.
Reply With Quote Quick reply to this message
  #24 (permalink)  
Old 07-13-2007, 01:31 PM
Registered User
 
Join Date: Jul 2007
Location: phoenix
Posts: 9
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Im only doing the v8 swap b/c my uncles are knowledgeable about chevy engines and could mentor me. the L28ET swap would be easier but I dont know many people that could help me with the swap.
Reply With Quote Quick reply to this message
  #25 (permalink)  
Old 07-13-2007, 01:45 PM
Member
 
Last photo:
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 50
Posts: 4,021
Wiki Edits: 0

Thanks: 0
Thanked 23 Times in 23 Posts
The engine is the easy part. Getting the engine bolted in place along with the cooling system, exhaust system, fuel system, electrical system, tranmsission mounts, trans shifter, clutch pedal, drive shaft, instrutment panel mods (tach, temp, oil pressure, ect), and hood latch relocation is the tough part. I hope your uncles know how to fabricate and have lots of free time.

A turbo engine swap is just about a plug and play compared to a V8 swap.
Reply With Quote Quick reply to this message
  #26 (permalink)  
Old 07-13-2007, 02:21 PM
Registered User
 
Last photo:
Join Date: Apr 2007
Location: Seattle, Wa
Posts: 6,651
Wiki Edits: 0

Thanks: 3
Thanked 398 Times in 345 Posts
Quote:
Originally Posted by k3werra
Im only doing the v8 swap b/c my uncles are knowledgeable about chevy engines and could mentor me. the L28ET swap would be easier but I dont know many people that could help me with the swap.
V8 swaps into Z cars is easy and a well traveled path. Since you have an experienced uncle and one of Mike Knell's cook books you're in good hands.

I prefer the small block Ford for this swap over the Chevy, it's narrower and 70 pounds lighter which results in more header space and a bit better F/R weight distribution. But since either the Chev or the Ford set back behind the front axle weight distribution compared to the Datsun 6 isn't too much of a problem.

The biggest hassle is electrical, especially if trying to adapt a TBI/TPI engine. But I even got a 302 SBF into an Alfa Spyder Veloce (vanity plate "V8LOCE")with no problems and what a wake up call that was. That gave the car the performance it should have had.

The other big problem is Datsun rear axle strength. While the 260 and 280 is a lot stronger than the 240 axle, you've got to be careful with a V-8 up front. An automatic softens the hit on the rear gears some which helps their survival, but in the end you may find a solid rear is the only solution. A 7.5 inch from an S-10/15 is almost a drop in. With a posi, cast rear cover, and Lucas High Impact oil that should be trouble free.

So break out the cherry picker and the welder and have at it, it's a very rewarding swap.

Once finished, parts are a whole lot chaper and way more available.
Bogie

Last edited by oldbogie; 07-13-2007 at 02:30 PM. Reason: correcting Mr. Knells first name
Reply With Quote Quick reply to this message
  #27 (permalink)  
Old 07-13-2007, 02:56 PM
Member
 
Last photo:
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 50
Posts: 4,021
Wiki Edits: 0

Thanks: 0
Thanked 23 Times in 23 Posts
Well travelled path yes. easy no.

240's came with R180 diff's. A R200 from a 280zx or from 280z that came with a manual trans is an easy swap. Just need the diff and a 280z mustache bar. Common ratio's for the R200 is a 3.54, 3.70, or 3.90. Typically 3.54 in the 280z's and 3.70's and 3.90's in the 280zx.

A 200r can handle 12 second 1/4 miles all day long in a 240. Axles and diffs start to break in the 11's range. And only good for a low number of 10 second runs. So, i don't think you need to worry about axles, halshafts, of diff gears until your engine starts making over 450hp. Stay away from slicks.
Reply With Quote Quick reply to this message
  #28 (permalink)  
Old 07-14-2007, 02:10 AM
DHMag's Avatar
Registered User
 
Last photo:
Join Date: Jun 2005
Location: InCahoots, Texas
Posts: 302
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Chevrolet4x4s
Not so sure about that one ............80 chevy 4x4 shortbed(2.76 gears?) with th350 and 350 -18mpg when new........1985 4x4 shortbed 3:08 gears with camaro 305 ho ported heads performer eps intake performer 1406 carb full length headers true dauls 700r4 trans........14ish
my 79 Malibu 305/350 gets 14in the city and close to 25 on the highway
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 2 (0 members and 2 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Distributor Tuning and Theory - Part 1 Rick WI Engine 35 04-26-2011 12:38 AM
buick 350 - chevy 350 72buick Engine 23 10-13-2009 08:38 PM
Chevy 350 engine swap motor mount question 78transam Engine 4 06-04-2007 05:57 PM
Will this work? Chevy 305 Throttle Body w/ Chevy 350 aberg12012 Engine 9 05-07-2004 12:28 AM
Reconditioning a small block 350 chevy v8 Butchardos Engine 1 03-24-2003 10:28 PM


All times are GMT -6. The time now is 10:04 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.