fuel mods needed to support 220whp on ka?

[brainfood]

I am thinking about building a high compression ka motor either 10.5:1 or 11:1 and am just working out a price sheet for parts and am wondering what kind of fuel mods I would need will I need bigger injectors and a fuel computer or can I get away with an fpr and safc for fine tuning? maybe a hacked 300z mas? any help would be great! thanks

[Var]

people say,and this is just what i've heard, that you can get away with a bone stock fuel system with 11:1 KA.

On the other hand..according to the magsquirt website..with 240 FLYWHEEL horsepower, you should be running 370cc injectors. Doesnt hurt to have the extra fuel i guess. And stock sr injectors will work on a DOHC KA. SAFC wouldnt hurt either but only if you had access to a wideband or a dyno with a wideband . Z32 MAF wont be needed.

Also from what i recall reading, you can just upgrade your fuel pump to a 255, and it should increase the injector output, but they will have a higher chance of failling.

[Maeda]

Can't go wrong with cheap SR 370 injectors...... for the piece of mind.

[orion::S14]

270cc/10.5 = 27.5lbs/hr

(27.5 X 4 X .90) / .50 = ~185rwhp for the max of 270cc injectors, assuming stock fuel pressure.

And even with a high comp motor, you WILL NOT break the ~185rwhp barrier, unless you have +$5,000 to WASTE on it.

And 11:1 KA with all the bolt-ons and tuning will get you close, but not over 180 IMO.

Stock fuel system will be fine.

- Brian

[brainfood]

I have seen close to 160whp dyno sheets from bolt ons on a stock long block, ie pulleys, flywheel, intake exhaust, header, grounding kit. I figure with a custom intake with slightly longer runners and a head built to rev higher with valve springs and new valves, also lightened rotating assembly plus the higher comrpession 200whp is more doable. Also the 370cc injectors arent too much bigger that they would still be able to be controlled with just an safc, plus the added timming advance from running bigger injectors would probably yield a little more power. Also if cams were implemented. Just wondering if it is possible to go 200-220 whp on an na ka. because if so for smog reasons plus the fact that it would most likely have a nice fat torque curve it would be a great motor for street driving.

[Jeff240sx]

I ran 4.35psi from a t4b s-trim.. non-intercooled.. auto tranny - for 2 years. It only blew when I replaced the wastegate gasket and a friend removed the vacuum line, and I neglected to double check it. And I'm sure I made over 185whp.
-Jeff

[orion::S14]

Originally Posted by brainfood

I have seen close to 160whp dyno sheets from bolt ons on a stock long block, ie pulleys, flywheel, intake exhaust, header, grounding kit. I figure with a custom intake with slightly longer runners and a head built to rev higher with valve springs and new valves, also lightened rotating assembly plus the higher comrpession 200whp is more doable. Also the 370cc injectors arent too much bigger that they would still be able to be controlled with just an safc, plus the added timming advance from running bigger injectors would probably yield a little more power. Also if cams were implemented. Just wondering if it is possible to go 200-220 whp on an na ka. because if so for smog reasons plus the fact that it would most likely have a nice fat torque curve it would be a great motor for street driving.

Problem isn't the valvetrain for high revs (stock is fine), but eh stroke is too long, and the crank isn;t fully counterbalanced. Basically, without a custom crank, you're limited to ~7500rpm and below.

And without those extra RPMs, you're not going much over ~170-175rwhp.

Do a little research, lots of guys have begun the same build as you, and gave up when the #s just weren't adding up as expected.

Hell, I did 161rwhp with my S14 (I/H/E, JWT ECU, S13 cams, ASP pulley, removed emmsions equip, no cat, base timign advanced, etc...) and it was great...but high comp was maybe ~5% more RWHP, and flywheel another 4-5rwhp...and then "wild" cams wold be the next wise choice, but with limited revs, you can't too wild...

Anyway, read up...you'll see that the math isn't there to support the possibility (only 2.4 liters, limited to less than ~12:1 compression to still make it streetable, and lower-than-average revs for a modern 4-banger DOES NOT equal big N/A power)...and other that have tried didn't get even close to succeeding.

My .02 - Brian

[s14 blacktop]

just in case you didnt know, you could also hack your maf to run the bigger injectors, since the 370 injectors are 37.037% bigger you might want to make your maf 37% bigger, this doesnt always work. some of the guys that did this found out that making the maf 37% bigger isnt always the solution and had to go back down to almost stock maf size to get the correct air to fuel ratio...
oh and you dont have to have the ecu reprogrammed for the 370's if you hack it...

but back to the subject anythings possible it just depends on your wallet....

you dont need the 300zx maf.

[Var]

orion s14: my friend dynoed his car on a dynapak. He has a DOHC with header, open exhaust, intake and SAFC with no dyno tuning. He made 166whp with full advance timing i think. Now you up the compression from 9.5 to 11. You port the head. Extrude hone the intake mani. Bore the block out 1mm. You get a pair of cams. Between all this stuff..i strongly believe there is 200hp at minimum to be found with this engine.

[orion::S14]

That may be true...but again, Dynapack reads a little higher.

And even factor in the port+polish, then cams...how much can that help if your revs are limited to ~7000-7500???

Then add high compression...good est for gains is ~4% for a 1 point bump.

Say he could do ~155rwhp (typical dynojet #s for those mods - We'll use a dynojet so we can compare accurately)...

155rwhp + P&P + Cams = ~170rwhp if he's lucky (the head and intake manifold are NOT that bad, there are minimal gains to be found there IMO).

Then lets add ~6% for higher compresison...

170 X 1.06 = ~181rwhp.

As I said...I tried it, and basically hit a wall @ 160rwhp with the bolt-ons. Sure, there is more to do than what I did, but they are NOT gonna gives big gains for a street car, when you're imited in size (2.5liter MAX) and limited revs (~7500 MAX safely).

We can "agree to disagree"...I just don't see the potential unless you can squeeze another ~1000-1500 revs out of it (read: $2500 custom crank).

- Brian

EDITED: spelling...

[phrozen]

my stock ka did 156 with just intake and gehtto exhaust

[brainfood]

sio the problem is with the lower end not the valvetrain as far as revs go? I thought a tuned length intake mani and some more revs there could def. be 20 more hp up there but if the shortblock wont support it even with a balanced/knife edge stock crank than I would have to agree that I wont see much power without more rev's. and if I cant achieve more revs than the ka just isnt going to make the power.

[Var]

orion...I guess we can agree to disagree but let's just talk some more about this

So let's say with header and full exhaust and a less restrictive air filter you can achieve 155whp, which people claim they have seen from the DOHC.

155

Then you get some pistons with a bigger bore and up the compression to 11:1

With your numbers, which seems like and underestimation, we should see about 10 horses just from the compression jump.

165

then we can add some more from boring it out

170

now we add some nice cams that like breathing all the way to redline

180

then we port and polish the head for all it has to offer and extrude hone the manifold and port match it to the head
let's include bigger valves and a 3 angle valve job

190

then we dyno tune it with SAFC with all the timing we can give it

200

maybe i'm oversimplifying it

[orion::S14]

I agree...in theory, it sounds that easy.

But in practice, the only high-comp KA with TONS of bolt-ons did ~171rwhp (now belongs to "RONIN", but used to be the 240SX.org guys car - 11.1:1, .020 overbore, S13 cams, ECU, pulley, I/H/E, S-AFC, etc...all the BS)

As for the underestimation for higher compression...V8 guys see larger results, but the 4-cyl BMW guys use 4-5% increas for 1 point bump in compression, and it proves to be pretty accurate.

And as I said...the stock head lfows FINE...there's just not that much power form P&P, or Extrude Honing, or even bigger valves. These tricks work great on old 2-valve heads with SH!TTY intake manifolds...but the KA is pretty good in stock form. I bet you see better gains from a properly desinged intake mani alone than all the P&P and big valves with a stock intake manifold.

And don't get me wrong, I'd love to see it done...but on "fair" or accurate dynos, it hard to break the 160rwhp mark. I can count on one hand the guys I've read about with charts from a dynojet that show +160.

- Brian

[Var]

i wonder how much of a difference aftermarket cams could make..

i get your point though. Seems un-japanese of Nissan to build this motor with no n/a potential. But they repsond amazingly well to turbos!

[orion::S14]

Best cams we got right now is the JWT set (similar, if not identical to Nissan Motorsports Stage 2, advertised 275 degree duration...really ~256/256 if measured to be compared with stock cams (232/232, 240/248)...)

...and the JWT cams move the peak HP out to ~6200-6300rpm, as compared to stock ~5700-5800rpm.

- Brian

[Var]

i think Gude racing sells a cam that pushes it even further up in the power band. I called and asked Bill Gude about it one day in the past. He said that cam would require you to remove power steering and a/c so it would idle. He also said you can make a SOHC have about 190whp if not 200, but then of course he's trying to run a business.

[brainfood]

And as I said...the stock head lfows FINE...there's just not that much power form P&P, or Extrude Honing, or even bigger valves. These tricks work great on old 2-valve heads with SH!TTY intake manifolds...but the KA is pretty good in stock form. I bet you see better gains from a properly desinged intake mani alone than all the P&P and big valves with a stock intake manifold

My whole idea was redline at 6500rpm with a intake manifold designed for a higher horsepower powerband not the short runner stock intake designed for torque. also with aftermarket cams not s13 cams but jwt's or the new billet cuts that I saw somewhere else.

[90RS13]

My whole idea was redline at 6500rpm with a intake manifold designed for a higher horsepower powerband not the short runner stock intake designed for torque.

I don't see the stock runners as being short, but just FYI, long runners are for being torqey (or low rpm power) short runners are for high rpm power. And the estimation Orion S14 is giving for compression gains are very good. Most people don't realize how little power you gain from compression bump. You do however get a lot higher thermal effeciency.
-matt

[brainfood]

sorry my fault I had them backwards but you get the idea. tune it more for high hp with "shorter runners" maybe even individual throttle bodies or heaven forbid dual webers or mikuni's 2 barrels

[orion::S14]

^^^ And that takes it out of the realm of "street cars"...

There have been KA24E (SOHC) motors with ~300HP...carb'd, race gas only, 8000rpm rev limit, etc...

Lookup Sunbelt Performance, or NASPORT...you'll find info.

- - - - - -

Anyway, every time there is one of these threads, I like to look at it from the perspective of a "regular joe", with a reasonable budget, trying to make his STREET car (most times his DAILY DRIVER) faster...and a N/A KA will not do 200rwhp and still be reasonable, it won't cost what the average guy can spend, and it will be close to not streetable.

The Bill Gude comment above is a good example...to use that cam, you have to remove A/C and PS...sounds normal to some of us, but it's pretty extreme.

- Brian

[citizen]

so the solution here to release the n/a beast is to get a custom crank, or build el frankenstein z block, l crank and ka head motor, to get past the 7800~rpm ka crank barrier

[Var]

nope...LS1

[brainfood]

yeah what about an l20b crank, or fuck it a z22 or z24 crank? even if you loose displacment you could make that up with the high comrpession and you could destroke that way. Anyone sonic tested the block to see how much you can safely overbore? there are a lot of questions no one is asking. also what about the VH45DE I think it could be made to fit doesnt weight too much more than a ka-t or sr20 with fmic and all the piping. only thing is I am not sure what manual trans bolts up to it or if a custom bellhousing would have to be made. I thought maybe the vq trans would bolt up if not an adapter or custom bellhousing could be made but the VH45DE is only $1700 used plus another $500 for harness ecu and find a used trans its not a bad option. Custom motor mounts arent that hard to fab and the wiring could be done pretty easily. Might be another option sinec i heard a chevy small block wont fit. plus it would still be nissan and all alum.

[Var]

Originally Posted by brainfood

Might be another option sinec i heard a chevy small block wont fit. plus it would still be nissan and all alum.

1- you heard wrong..it fits. there are finished projects out there

2-"still being nissan" doesnt mean shit when that engine is a big pile of poo that's expensive to fix and/or mod.

[s14 blacktop]

I think he needs to do some searching before he makes anymore replies...
just a couple of weeks ago a guy posted about putting a ls2 in his engine bay and he took pics of it..

[brainfood]

I think he needs to do some searching before he makes anymore replies...

Im looking for a discussion on going n/a in a 240sx not looking for someone to give me all the answers to all my questions right here right now just looking for everyones opinions. I have my own ideas and I am just trying to get some feedback.

2-"still being nissan" doesnt mean shit when that engine is a big pile of poo that's expensive to fix and/or mod

Its cheap though used ones are only $1700, I dont know anything about it so I was just seeing what people thought it is all alum. 4.5l v8, what about the qr25de or the vg35?

[sideviewcivic]

hey brian i used your formula to calculate the amount of power 370cc injectors could handle. I used 9.1 compression with 370cc injectors, etc....i came to roughly 292HP but thas at 40.6lbs/hr IIRC. what is the optimal fuel pressure on a KA rail so i don't have it fail on me.

-Aaron

[North240]

A KA is not a honda motor, ie not high HP NA 4-banger. If you have money to blow then go for it, and in that case upgrade the fuel pump, injectors and get a ecu re-tune. Good luck remember to post back with results.

[brainfood]

what is the formula to figure out how much hp per liter at a certain v.e. and rpm? Also anyone have any links to a running v8 conversion I heared that a small block with alum. heads only wieghs less than 100lbs more than the ka. Just curious. this car with a v8 would be the ultimate pony car. Might not want to do it for a comp. car but it would be fun as hell on the street.