windshield wiper cowl on 91 S10 Blazer...

[overs10ded]

Hello, newb here, I have a '91 "brick" 4dr S10 Blazer 4x4 that I will have for a long time to come and want to know if anyone has experience with the effects of the Lund wiper cowl covers concerning better aerodynamics covering the wipers. I think they look cool anyway. I also have a short cowl hood-2 1/2" which rubs the driver wiper when opening the hood so I don't even know if the cowl cover would work with my brick. Any experience appreciated!

Good times!

Bruce

[NeilBlanchard]

Welcome to EM!

Covering the windshield wipers makes almost no difference to aero drag. That area on most vehicles is a pocket of high pressure air that barely moves at all. There are several things you can do to improve the aero drag, but the wipers are not one of them. I'll let folks who are driving similar vehicles post about what works best.

[overs10ded]

Thanks Neil for your response. I'll scratch that in favor of spending the money elsewhere (when it comes available!). My other vehicle is a 1986 toyota tercel fwd station wagon that exhibits similar eco-challenges to the Blazers aerodynamic design-ie; brick!

Bruce

[agent00kevin]

You would benefit a lot from a drop in suspension with that truck. Ive got a 88 S15, same brick front end, and it is lowered 2" front 3" in the back. A few other Mods that dont pertain to your truck (diff engines) and it gets 34mpg solid and consistently.

[overs10ded]

Yea, I converted my front suspension to coil-overs and deleted the old torsion setup saving some weight as well as lowering the front end about 2", and my rear is lowered 1", but both could go an inch lower but probably with a tire downsize as I'm w/17's at 31" tall!

You must have a 4cyl (diesel maybe??) w/ that mileage! GREAT!!

I'm mostly looking at aerodynamics at this point...tuning the ecm...synthetic oils all around...front air-dam, maybe side skirts? Biggest area of question is the rear of the S-10 Blazer...I'm going to go to a steel roll pan from the oem bumper. Thinking of a partial Kammback or vortex generators maybe...

Thanks for the reply!

Good times!
Bruce

[wmjinman]

I found the biggest single aerodynamic improvement was from a grill block (watch that you don't overheat, though - I ended up having to cut a 6" diameter hole in the middle of it). I think that one mod was worth about 1.4 MPG.

Of course, decreasing my speed had an even bigger impact. At 40mph, I get up to 5 MPG more than at 60. And the increase was fairly linear, all the way from 40 MPH to 80 MPH. At 35, it's worse, though. 40 is the best, where I actually get 30 MPG or better!!! No joke!!!

Other improvements: taking the roof rack off was good for just under 1/2 MPG improvement. Folding the mirrors back flush with the sides was only worth 0.1 MPG, and adding cardboard "fender skirts" to the back wheel openings was negligible. - I tested it 3 times, once with a miniscule improvement (less than 0.1 MPG), once with a miniscule DECREASE (still less than 0.1 MPG), and once with virtually no change. Pumping up all the tires to 60 PSI (from 45) was worth about one MPG if I remember right...

But my car is a 2000 Jimmy, which is, I think, a different body style and engine than yours. I had an '85 Jimmy before this one, which was the "square" one. Didn't experiment with aero mods on it, though.

[overs10ded]

I have an intercooler in front of my radiator, and a trans cooler, also the a/c evaporator so I'm concerned with stopping too much air from coming through the grill, however I think I could probably block "neutral" areas and help things.

Surprised about the mirrors, thought they might be worth more. I have deleted the luggage rack. I have a body kit to install and an airdam-stock, that I haven't run for a very long time so I hope these might help some...also wanting to delete the rear bumper in favor of a roll-pan. That would save weight as well. With this body and the second generations too, I think something along the lines of a partial camback might work.

Thanks for your mods and help. Very good info.

Good times!

Bruce

[wmjinman]

Hey Bruce,

An intercooler!?!?!?! Are you turbocharged?!?!?! I just went to your vehicle info and it doesn't say much. No "fuel logs" either. ???

I have an a/c evaporator in front of my radiator too, but since the a/c hasn't worked for a few years and I don't seem to be worried about it, I just went ahead and did the grille block. You definitely want to keep an eye on your engine temps if you do the grille block, though.

I think a kamm-back or full boattail would be beneficial, but as big of a rear "wall" as our cars have, it would probably have to be one helluva boat tail!!! I'm kinda thinking about some sort of "boat tail trailer" like I've been reading about on here. Actually buying a cheap(ish) trailer & then using that as the base (extra tail-lights and all) might make the most sense in this application.

From what I've read on this site (and I admit I haven't read it all), it sounds like the so called "low hanging fruit" are:

1) Slow down. Drive as slow as you can get away with, and that will have the biggest impact.

2) Air up your tires. I'm sure liability prevents anyone from suggesting going OVER the max. pressure written on the sidewall, but I'm crazy and do it regularly. I find that 60 psi in the tires yields really good results (fuel mileage-wise)

3) Grille block. Do as much of it as you can, while keeping one eye glued to the temp. gauge so you don't over do it.

4) Kamm-back/boat tail. Boat tail would probably be the top overall improvement of all, but obviously, not a quick or simple one - therefore, probably doesn't qualify as "low hanging fruit", but if you want to do one thing that makes the biggest mpg difference - in the aerodynamics realm - that's probably it.

5) And, of course, driving style. While not an aerodynamic mod in itself, if you drive like the pedals are not your friends (touch them as little and as lightly as possible), and learn how to "coast forever" when approaching a stop sign or light - - - or parking spot, that will help a lot. Your car is probably too old for a ScanGauge, but those things are worth their wieght in gold when it comes to showing you what's happening. I just love turning my engine off while rolling up to a stop and watching my average MPG for the trip click up and up and up. Of course, when the light turns "green" and you gotta start it up and accelerate, you get to see the other side of that coin, too!!! But it really shows you what's happening, and as always, the more you know, the better off you are.

Oh, and your air dam: From what I'm getting here, you don't want to increase your frontal area with one. So as long as it doesn't hang down any lower than the other un-streamlined stuff on your car hangs down, then you should see gains. But better yet would be a "belly pan" that actually streamlines the underside. If I ever get super-ambitious, that's what I plan to do. At the speeds I drive this thing at, I'm not worried about "front end lift" or getting any "downforce" - just a smooth surface for the air to flow by...

Hope this helps. I don't mean to "preach", even though it might sound that way.

edit: Oh yeah, the mirrors. Yes, I was dissappointed, too. I was really hoping for a bigger result from that.

[overs10ded]

Yes, great info!! Thanks!!

I am using a '96 4.3 vortec with a 2001 '411 pcm and I am running a Procharger centrifugal supercharger and that is the reason for the intercooloer. I use EFILive for tuning and have a lot of work to do in that department.

Also converted to all 2000 s10 Blazer brakes and suspension, disc brakes ft and rear and sway bars ft and rear, big upgrade from the original '91 stuff. Also replace the torsion bar front suspension with coil overs that works really well so far!

The boat-tail trailer idea is one I really like, as I am a camper and like to take extras along with me. I'll have to look into that more carefully.

No fuel logs posted, I have best mileage of 24.1mpg with current running 21-22mpg but I have a lot of room in the tuning that I haven't tapped into yet. Later on in 2013. This is my stateside vehicle that I have owned since 1999 and logged 125k miles on the Blazer but I live in Costa Rica...here I have a 1988 Jeep Cherokee with a 2.5 Hyundai turbo diesel, and a 1986 Toyota Tercel stationwagon...just got a new record of 33.5mpg this last tank, fuel logs since new with every fill up at the same pump in the same station to the same just barely overflowing point of the gas filler neck.

I drive the Blazer when I'm in the states.

Thanks for your info! Not anything new for me but worth pointing out!

Good times!

Bruce

[wmjinman]

Ah, thanks Bruce. Interesting stuff. Wow, sounds like you've done a lot of work!!

Yeah, the boattail trailer is an intriguing idea - especially if you're doing primarily highway driving. I'll bet it would get really old really fast if you had to negotiate tight spaces & back up a lot!!

I've been thinking about a way to boattail my Jimmy, but to follow the "template", as aerohead has supplied, it would have to be either really long or else only a partial. The trouble with the trailer, other than the manuevering, is the extra drag from the extra two tires, and trying to make it so it can turn but not have a big gap when going straight.

There was a pretty long thread on here I read the other day, and wow - lots of designing!!!! Can't remember who it was doing it & who it was helping with the design - - - I want to say MetroMPG was involved, but couldn't swear to it.