jmoretti13
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hahaha, i get 10-12...but I do have 35" tires and 4" sus lift. can't keep my foot out of it
Fuel efficiency improvements
- Thread starter rdhenderson
- Start date
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hahaha, i get 10-12...but I do have 35" tires and 4" sus lift. can't keep my foot out of it
billiam7787
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ok, nothing too impressive, upgrades/mods are as follows: spider, real cold air intake (completely enclosed section with air funnel), high flow cats with megan racing exhaust, copper plugs, 18" fan, local tune, and light syn oil. as an added bonus, my driving tires are 235/95/16.5, which were the tallest, skinniest tires i liked. stock gearing. trans cooler. and last but not least, i used about 2 and a half liters of acetone, one cup every full tank. i can guarantee that helped me a ton. it helps with all FI gasoline engines, just make sure u dont spill any on the paint, it WILL eat it.
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My '97 without any mods gets 15-18 all around. It has 139,000 miles on it. I knew that when I bought it used and it has been right in that range. I may go to electric fans and water pump if the cost isn't too high. On this old Tahoe, I don't see the need for much in the way of mods. After 2 years, I'll probably just donate it to Purple Heart.
I'm not sure if this pertains to you but there is an updated crank position sensor to fix that, had to do it on my dad's truck, damn thing barely wanted to crank some mornings.
atis
Full Access Member
Wally, I will look into the new crank sensor. I figure with 180,000 miles its getting near its life expectancy. The hard start was the fuel pump...had the dealership replace it. I now have a life time warranty on the FP, 3 yr 100,000 mile on the motor, and 3 yr 100,000 on the tranny...dang its like a new truck.
Ok, I managed my best mpg ever.... 19.1 mpg!!!! Disclaimer is that I drove 190miles of freeway and only stopped once so my daughter could get a soccer ball at Dicks Sporting goods. We live in a small town so wally world is the normal shopping location.
Ok, I managed my best mpg ever.... 19.1 mpg!!!! Disclaimer is that I drove 190miles of freeway and only stopped once so my daughter could get a soccer ball at Dicks Sporting goods. We live in a small town so wally world is the normal shopping location.
SunlitComet
OBS Jedi-Do Good
Still good mileage.
Firstoneman
Member
ok, nothing too impressive, upgrades/mods are as follows: spider, real cold air intake (completely enclosed section with air funnel), high flow cats with megan racing exhaust, copper plugs, 18" fan, local tune, and light syn oil. as an added bonus, my driving tires are 235/95/16.5, ...
Can someone give examples of manufacturers (perhaps links too) of these "spiders"? Also, good suppliers for electric fans for a '99 5.7l Tahoe? Any brand/size fan better than another? Are they complicated to install (i.e. wiring)? Am attempting to improve mpg on a new-to-me Tahoe.
Thanks. D
hahaha, i get 10-12...but I do have 35" tires and 4" sus lift. can't keep my foot out of it
With 35's and a life 10-12 is great mileage for these trucks!
SunlitComet
OBS Jedi-Do Good
for the fuel spider go with this unit. It is from an OEM supplier and comes with the bracket as well. There are different fan setups you can use but a complete ready to install kit would be the flexalite 280 it comes with everything you need and is pricey at $549.Firstoneman
Member
Thanks for the
Lots of great info here - though I'm finding it a bit difficult to decipher what will make the most impact on fuel efficiency up front. Seems like offloading the fan is immediate impact on engine efficiency - but $549 is steep. The spider may or may not - I haven't even driven this Tahoe - picking it up in Texas next week. I figured with a 1400 mile drive I could start the savings right away by doing a couple mods before I got on the road. But really, it seems like I might need to know how the Hoe performs currently before trying anything. Am told it gets around 13-14mpg - combination mileage. I'll pick up some acetone per Billiam's thoughts. It does have 3.73 rear, an L31 5.7liter, and 4 speed tranny.
Any other options on the fan? Or, on the spider for that matter? What brand copper plugs are preferred/used by some?
I am a bit perplexed by these vehicles lack of fuel efficiency - generally. I see some get "okay" mileage. My 1991 Chevy ext.cab, 4x4 1/2 ton p/u (210,000+) gets better mileage (16mpg-5.7l 350) than the Tahoe I'm picking up - and about 13-14 when I'm hauling 3 tons of stone plus tools - I do have a 5-speed manual tranny. Just wondering how this all really works. I have a 96 Explorer and a guy on a forum with a similar vehicle built his 6cyl Explorer up to 34mpg - better than my Acura Integra. A buddy of mine with a stock 4x4 1999 V8 Explorer (kept tuned) gets 19 mpg - no mods. So it is possible to create significant efficiency gains in some vehicles like these Tahoes.
Cheers and Thanks!
Dave
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SunlitComet
OBS Jedi-Do Good
Some people here use the Lincoln Mmark VIII fan in there trucks and easy to get from a junk yard probably. Don't use a different spider as you may not find a better and cheaper. Delphi has it OEM hands on almost every car out there. The delphi/acdelco brand will run you $450 at most local stores so that is a $200 savings already. If using stock ignition the ac-delco platinum 41-993. if full msd ignition setup the autolite 605 gap at .060. WHen it comes to parts or upgrades get your part numbers together and shop amazon or rock auto first then branch off into jegs or summit before going local.
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Firstoneman
Member
So, will the spider help with better mpg as a rule? Or is it just a power performance gain? I've never explored this kind of mod before. Again, keeping in mind my primary interest is better mpg, is there any validity to just doing the complete msd ignition mods? if I decide to be into this vehicle for the long haul, the sooner I put these mods on the sooner they each pay for themselves (if better mpg is to be had).
Thanks and I'll be keeping your suggestions handy.
Dave
PS. Did you mean Mark VIII (8)? Thanks.
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SunlitComet
OBS Jedi-Do Good
sometimes. It is more of problem waiting to screw up your day. It really depends on the condition of the old design. The old design had problems with working properly so much that gm extended the warranty of fuel injectors to 10yrs./200,000miles. the injector have improved fuel atomization. With a whole msd system you will get a more complete burn and of course more out of each drop of atomized fuel. Intake work would increase the flow properties of getting the mixture into the cylinders.
I meant 8. corrected.
---------- Post added at 11:29 PM ---------- Previous post was at 11:28 PM ----------
Of course you driving habits help a lot too.
I meant 8. corrected.---------- Post added at 11:29 PM ---------- Previous post was at 11:28 PM ----------
Of course you driving habits help a lot too.
Firstoneman
Member
Sorry, but I'm not following you. Is a new spider the thing that's waiting to screw up your day, or the original factory GM design?
So, how do I know if original is bad or if it's working properly? Are you saying GM's injector warranty solution has "improved fuel atomization"?
What suggestions do you have for the intake?
Thanks.
D
SunlitComet
OBS Jedi-Do Good
Sorry about that. old design is bad design and sometimes give the impression something else is wrong other then itself. newer design is better. It can be hard tell if they are causing a problem unless you can actually see the flow so if you have 100,000+ miles on them then just chuck them for the new design. some problems are leaking, clogging, bad spray patterns or pressure regulator failure/leaking. Reading spark plugs can clue you in a little on there condition.
For intake you can go K&N FIPK $230 9+ hp, vmax spacer $220 20+hp and a ported TB $100-300 gain varies. And the gains listed here are what the makers claim on dyno sheets. I have the FIPK, want to do TB soon but may have to wait till I get a taller hood for the plenum intake spacer because my intake tube is already touching hood a tad bit
For intake you can go K&N FIPK $230 9+ hp, vmax spacer $220 20+hp and a ported TB $100-300 gain varies. And the gains listed here are what the makers claim on dyno sheets. I have the FIPK, want to do TB soon but may have to wait till I get a taller hood for the plenum intake spacer because my intake tube is already touching hood a tad bit
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Firstoneman
Member
Thanks for the clarification. Will wait on that mod for a bit til I know the vehicle better. This Tahoe was good deal = free.
With all that HP gain (even if I netted a quarter of it) - will I lose mpg? Thanks for all this info. It will definitely be helpful.
Cheers!
Dave
PS. Am looking for a manual. Found a set of 4 $100+. Also finding dvds on auction site - $30+. What do you think?
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SunlitComet
OBS Jedi-Do Good
The general belief is that if those improve hp then it does not take as much gas to get the same power output and vehicle speed. I don't think there is a specific documented case or study but I am sure it does maintain or improve things on a mileage point of view to a certain extent. One day I intend to have everything from intake to exhaust done. including some new rocker arms.
As far as manual goes I use a web based system which contains the factory data for coverage from Tahoe, Blazer, Yukon, Escalalade 1992-2000 carryovers. And a 2005 ford escape for the mothers car. Printed is good but take care of them. Do you have a link for dvd type?
As far as manual goes I use a web based system which contains the factory data for coverage from Tahoe, Blazer, Yukon, Escalalade 1992-2000 carryovers. And a 2005 ford escape for the mothers car. Printed is good but take care of them. Do you have a link for dvd type?
Firstoneman
Member
I kinda figured that but thought I'd ask. I am certain that air to exhaust tip can help mpg- my mods on my integra have proved that - and it definitely helped seat-of-the-pants experience from the very lackluster auto tranny.
here's the link: http://cgi.ebay.com/ebaymotors/ws/e...item=&sspagename=STRK:MEWAX:IT#ht_8539wt_1173
Thanks again.
Dave
SunlitComet
OBS Jedi-Do Good
Would not touch it. To many selling points on a long page should caution anyone looking. It is cobbled together from different sources. BTW GM uses Alldata because the data on there is from Gm's own data. And Alldata automatically applies service updates.
Firstoneman
Member
I've always suspected that is why the Toyota Landcruisers with diesels get such great gas mileage. Hmmm...what happens if I put a diesel in the Tahoe, change the gearing, and add skinny tires?
What are you using and is it available to me for reasonable price? I suppose if I put a diesel in me Tahoe, there'd be no manual for it.
I do like the Tahoe style - both OBS and Second iteration (what are the initials for 2000+ Tahoes body style around this forum?). Not sure about third gen (is that NNBS?). So if I can find a way to justify keeping this long term I WANT to do it. But mpg is a stickin point for me. It will probably end up being the replacement for my '91 1/2 ton and '96 Explorer. Between those two I cover everything I need. I'd like to think the Tahoe will fill both duties well. So maybe I go with a diesel conversion. A friend of mine loves cummins and knows them inside out. He might be able to help me find one for a good price - the deals he scrounges up are amazing. Okay, sorry I digress.
Thanks &
Dave
