I know most of you guys on here do not drive ur vettes everyday. But it seems like anyone that is pushin over 300hp that i have seen has a carb on top. I understand it is easier to make power with a carb but mpg's are not there anymore. Its better mpg to have the tpi on top. I have a 89 cherokee with a l98 stock internals, msd ign, accel dist, wires, intake, full exhaust. Um looking to make a long road goal for my jeep. I drive this jeep daily year round. Um debating between supercharger or topend build (heads, intake, cam). I figured supercharger might be a better route because it makes the engine more effecient yet it only eats more gas when u stomp on it compared to more air and fuel on a topend build. I know ill lose a little mpg's. What route do u think i should go with? 300hp to 400hp would be my goal. Enough to have fun yet not a drag only motor.

Heres my vid for more details of my jeep

http://www.youtube.com/watch?v=evQJ_ki1vb8

 

Nice Jeep Cherokee with an L-98. Cool!

 

44 dana even

 

Thanks guys



I understand this is a loaded question. I was hoping somebody would point me in the right direction and a lil info what i should do.

 

miles on the motor?

whats' dollars in your wallet?

I'm hovering around 500hp, I get 11.61 combined, it sucks, I wish it was better.

 

80 to 100,000 miles. Um unsure but within that range. Lets say 5grand.

 

My stroked 383 with 375whp and 376torque gets 17 and 24 mpg. That's with stock gears and auto transmission. And i'm not gentle.

 

build top end IMO
thats alot of miles for a boost app
Im putting well over 400tq but under 350hp
intake is a downfall on these cars but in a cherokee if you want to go mudding the tq is better

so what do you want to do with your jeep?

 

I figured supercharger might be a better route because it makes the engine more effecient yet it only eats more gas when u stomp on it compared to more air and fuel on a topend build.

It does not make the engine more efficient, it basically simulates making the engine higher displacement, by pushing more air into the cylinders than would normally be possible. A supercharger has some parasitic draw at all times, as revs increase you go into a net gain situation. Sitting at a stop light you are burning extra gas (maybe not significant though).

 

Youll lose mpg regardless..For a truck a SC would be the ticket as you need plenty of torque to get it moving, Im guessing 4-6 lbs of boost would get it moving well and shouldnt be too hard on the bottom end.

Also theres plenty of ways to make power with EFI these days. Most that dont understand it toss a carb on it.

chp or at the tire? Im skeptical that a stroker could pull off new bone stock L98 mileage

 

can you send me a bin file to look at?

 

I get 18.66 mpg with my 383 and 3.08 gear and shift kit
and thats a mix of highway and city
Im sure if it was all highway and not running a lil rich I could get 21 or so

 

My '85 has a little over 300 hp (crank) and still has an unmodified tpi on top. I've upgraded the fuel system a little but the rest is bolt ons. To be completely honest i'm not sure I can get anymore horsepower out of it using the tpi though. btw I get about 18 city/26 highway.

 

I'm around 400 at the wheels and today on a 80+ mile trip I was getting 25mpg. I have gotten over 30 on the hwy if I don't get on it....today...I was on it!

 

Sorry to hijack, I miss your avitar.

 

at the tires.
You're welcome to take it for a ride and see for yourself

 

Im saying s/c

 

I'm 338rwhp/400rwtq and on a highway trip where I was trying to get good mileage, I pulled 26mpg.

I'd rather have 400whp and 25mpg though...

 

Lots of interesting responses, but I want to make sure that you understand that due to this engine being in a different vehicle, your needs are different than if it were still in a C4 Vette.

Besides driving style, the single most important factor effecting fuel economy is weight, the second is aerodynamics. The weight also has a dramatic effect on the acceleration. A heavier vehicle requires added low speed torque to get it rolling.

For your application, however you decide to go about adding power, make sure you keep low speed torque in mind. A supercharger will indeed increase power across the entire RPM range making it something to consider for your application. A stroker will also add low speed torque making it a good choice. A supercharged stroker REALLY adds some low speed spunk.

If you are doing alot of the work yourself, I would think that a supercharged 383 would give you decent power without killing the bottom end while possibly being within your budget. It will indeed use more fuel than you are currently, but you don't get something for nothing.

If your primary goal is fuel economy, a near stock L98 is a pretty good combination. It runs out of steam at 4,500 RPM, but makes low speed torque by the gobs. Torque is what you need for your vehicle, not horsepower.

If you want fuel economy, a budget build, and some extra torque to get the heavier vehicle rolling, a 383 stroker along with some bigger runners for your TPI would be a good compromise IMHO and be within your budget. Also a set of full length, small primary headers will give you added torque and help fuel economy. I would put the headers high on the list.

I've been doing some messing around with Desktop Dyno and have learned that the two best normally aspirated mods for adding low speed torque are: full length, small tube headers and added stroke.

My $0.02,
Doc

 

My stock L98 M6 would get an indicated 28-29 MPH on the highway at ~75 MPH, even with 4.09 gears.

Now, with the stroker and mini-ram, I get 24 indicated on the highway. I haven't checked actual mileage, but that is what the indicator says.

It get's about 15 around town, and will go as low as 10 if I am out playing.

I agree with the blower idea for your application. Blower works is probably who I would use.