I want more power from my 308 .. what shall I tackle next?

Hey all,

I have various motors in the works right now but there might be some fundamental things I can do on my current setup to get some more power .. .appreciate any thoughts and input.

1. throttle body . . I have one I bored out and made a new blade (2.7" from memory?) etc. like Kermit did . . . I just have to bore a plenum to match I guess 'cause no power gains without the plenum match right ?????

2. I'll post a recent pic of my motor here in a few but my intake system could probably use some improvement . .. just a piece of hose making 180 deg bend to the throttle body (stock 2Vi TB & plenum etc.) from the air scoop area . . K&N style filter on the end . . am I going to see power gains you think if I put the air cleaner right at the throttle body and run a cold air feed/box to it?

3. ignition . . I'm running a MSD Dis4 which puts out 180 mj (roughly .. memory) but I'm splitting that between 2 denso coil on plugs . . I have a second Dis4 just kicking around and MSD said this would make more power 'cause of the spark split with waste spark.

4. I have a second ECU to run 2 or would consider buying another one which facilitate full sequential EFI and no waste spark.

5. Play with different plugs?

6. Move the injectors further down into the intake stream? . . .don't think this will make more power would just fix some problem if I was having one.

7. Vacum pump to evacuate the bottom end.

8. anything else? ..


my motor is around 11.5:1 compression and it's got a stand alone EFI and ignition brain and feel I've got a lot of timing already (36 full but mix in some avgas for safety) . . injector duty cycle about 75-80% @ 8000 rpm.

she made 210 hp at the rear wheels but she feels stronger with the increased plug gap already .. .

thanks,

Sean

 

boost isn't on the list .. it's too easy

 

On #1 -- a dyno test with the old Kermit stuff showed a loss in power with a bored out TB and a mismatched plenum.

see http://ferrarichat.com/forum/showthread.php?t=88743&highlight=kermit+plenum

 

I don't know if they'll fit, but I've got a pair of 4-valve heads that I'd love to get rid. Likely they'll need some freshening...as I recall they've got a couple of tweaked valves.

Let me know....

David

 

I've got a few other 2V motors in the works with bigger cams/porting/intakes . . etc. .. swapping to 4v heads will just complicate things even more

unless they're really cheap? .. I'm always a buyer then.

cheers.

 

what's the quick answer on power gains with it all matched .. . . .. . .. bueller???

 

was thinking if there was power gains here . . . I should definitely address item 2 first 'cause this is pretty easy .. . and guys were spending a bunch of time on carb air intakes weren't they? ... mine's gotta be horrible for power yes??

thanks,

Sean

 

other thing was independent throttle bodies ... I have some carb intakes but it's a lot of work and I think what I've listed is kinda simple

edit: . .. work or money depending on TWM's or motorycle units but if there's the big power gains me wants

 

a 12 cylinder would be a good start. A TR drivetrain will go without a lot of work and give you 420hp stock and 500ish with a little work.

For the V8, I don't really like the carb intakes, too many curves. If you make a simple straight intake for the motorcycle TBs with will make more hp and spend a lot less money.

After that the heads don't flow nearly enough air. With the heads proberly ported, your hot cams and the motorcyle TBs you should pick up 50rwhp without much trouble.

If you want to add torque across the board, a 360 crank and liners will gain you 20% more everywhere.....heck the heads have the same bolt pattern you could add those too and make 400 hp easy. All these parts are sitting in my basement, they aren't mine but I think they are for sale and can put you in touch with the owner if you like.

Have fun

 

Hey we lost a couple posts from DaveH and Mike996 .. .

I have a couple other motors in the works with bigger cams, etc. .. here's the dyno curve for the motor that's in my car .. just seemed like that intake hose was a real power robber the way guys seem to talk about throttle body size and cold air feeds for carb cars??? . . because I have other motors in the works want to try and not take this car off the road for any mod's/experiments.

also Mike I have an Innovoate system with accelerometers to be more scientific than just seat of the pants when the time comes.

thanks all,

Sean
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Mike you mentioned optimizing torque . . my motor has a great torque curve I think . . pulls pretty flat from 2500-6500 . . anyway just looking for more without tearing into 'er . . I have another 308 to drop one of these other motors in and the bigger cams will probably effect tq, etc. but way more power I hope.

thanks,

Sean

 

For all of us that do not have Mark or Lucky's fabriation skills, it's important to know that QV heads and 2v heads will bolt up, but have different oil passages and will require signifigant re-work amd modification to fit. Same for the 360 crank - the journals will drop in but both ends are going to require substansial modification.

Best
rt

 

There you go getting all practical again

 

If you are not planning to tear into it, then the only significant improvement available is to add boost I think.

 

You're not a believer in the bigger throttle body or re-doing the cold air intake and have the air filter pretty much straight on the back of the throttle body?

 

You must remember that Mark's idea of a significant hp boost as compared with gerneral population is somewhat skewed, as witnessed by his not giving a second thought to dropping a 5 liter 4cam V-12 in a 308.

On the other side there is me, trading in 20-30 hp bumps by polishing the existing package.

My plans are subtle, understated and easily achievable, while his are spectacular, galactic in scale requiring complete re-engineering.

 

On my list which would you try first?

 

I'd be real happy with 20-30 hp bumps .. . I think I'm looking for maybe 5-10 hp bumps on this package.

Keep in mind Russ your plans are easily achievable with a massive budget . . the only significant mod on my motor is the compression ratio, unless you consider the EFI a significant mod which I don't . . . I think you can achieve the same hp with the Kjet . . just not the same throttle response.

cheers

 

I have a sweet nitrous setup but I want to wait 'til I get a spare motor or 2 on the shelf

 

You can always save the money on these mods and put the funds towards a 512 BB...

 

I wanna go faster though

you'd be shocked how little I spend out of pocket on this stuff . . . really really really shocked

 

not to mention I just cringe when I think of the cost of rebuilding one of those motors if I really hurt it . .. 308 2v's are just darn cheap when you're a DIY'er .. especially since there's so many fire motors and not many people have their own machine shop to save 'em.

 

You absolutely could not have achieved the same hp with the CIS....it doesn't flow worth a sh*t. The quote I'm found of is "I don't care if you're Jesus Christ himself, without air you aren't going to make hp."...and with CIS you don't have air. The EFI conversion alone is good for 25-30hp on a QV. I'd guess a bit less on a 2v, but would yield the same 25-30 when combined with early carb cams.

The problem with getting more is that you are now pretty much out of flow. The heads and manifold are well matched from the factory with the manifold out flowing the heads by just a couple cfm. Radical cams will gain you a little more, but will cost you bottom end becasue the rest of the engine isn't matched to them. Playing with the exhaust, cold air intake and the like might gain you another 10rwhp, which isn't nothing but it will take a lot of playing around to get it.

$200 will get you an eaton M90 blower on ebay and that will easily give you 10psi manifold pressure....which is about a 55-60% hp bump. Prety hard to beat in hp/$ math.

 

While I agree with this conceptually and in my own wish list, every decent Boxer is now $100K north of a 308.

 

Yeah and this is the problem with the throttle body, intake and heads right? is it really that much of a restriction when you compare the flow numbers to all these components? . .. yeah I know it's the case with big flow numbers but with everything flowing like crap . .. ??? . .. series orifices have much less of an effect than when you have one big flowing pipe and one orifice . . . meaning series orifices of the same size do not cut the flow down proportionally like one orifice does.