NA Build?

[Ajax]

Boost Heads. That's my new insult of the day.Vin, what's your take on the Xcessive intake manifold? Obviously its designed with boost in mind- what kind of changes would you make?Asking because I'm planning on getting one, then trying some custom plenum designs for a dyno-comparo.

[Bigvinnie]

Boost Heads. That's my new insult of the day.Vin, what's your take on the Xcessive intake manifold? Obviously its designed with boost in mind- what kind of changes would you make?Asking because I'm planning on getting one, then trying some custom plenum designs for a dyno-comparo.

I wouldn't use it at all, the design of that manifold is for manifold pressure.Runners are also to short which would effect high end power and disrupt intake manifold flow.

Personally when the manifold first came out I thought it would be great for an NA application. After further review and insight on reading some books on fluid dynamics my whole reasoning changed from liking it to not liking it..

If the KA had larger displacement and was less rev happy from Bore X stroke, then maybe I would think or consider, it could possibly work better with something like a brian crower 2.6liter stroker kit, but I don't see it working well with stock displacement or higher compression.

I think because the TB and plenum are so large on that excessive manifold you would probably spend months trying to retune your cas and K values, it just seems as if it would actually slow down velocity as it passes through the MAF. Now if you were to use a MAP, I think you could run into problems with calculating manifold pressure if there would even be any, using such a large plenum to it's displacement.


Modified by Bigvinnie at 8:49 PM 9/10/2008

[Ajax]

Well, now that you mention it, I do have a stroked engine. I had AMS build a BCstroked KA with 10.5:1 compression, AMS race head with BC V3 cams, JWT ECU with AFC NEO piggied.I've got plenty of torque, and the hp is there for the meat of the powerband, but it still falls flat above 6k. The fuel had to be leaned out as it simply wasn't getting enough air up top- leading to the theory that the intake manifold is severely limiting airflow. Hence, experimentation with intake manifolds is expected to make huge impressive gains. Since there is no complete custom manifold design out there, we are left with fabbing up our own or modifying the stock. To me it looks like the Xcessive runners are about the same length as most ITB setups (ITBs just too expensive at this point), so it seems plenum size and shape would be the first place that we should try modifying (also the easiest since we can make a template with the runners and make several copies, and dyno several different versions in relatively little time).

[480sx]

Never said that dyno tuning itself was abstract, just the number that you were left with was.

Its a well known fact that dyno hp is not a true reading of HP, and is not set in stone. Each dyno measures HP differently. Sure, comparing one car on a dyno jet to another car on a dyno jet is a good comparison. However, these numbers are not written in stone true hp. A dynos primary purpose is to be a tuning device to let you dial in more power from your engine. The real standard of HP is measured at a track by figuring out what your trap times are compared to the weight of your vehicle. That is the universal standard for measuring hp.

You guys are making it sound like 200 hp is an easy feat with a Ka, when its not at all. Out of EVERYONE who has done a N/A Ka build you'v got one guy whos broken 200 hp, on a dynojet. Dyno jets give you those feel good numbers, put the same car on a mustang dyno and you probably wont be over 200. Seriously, a dyno jet reads way to high for everything. Once again, dyno measured hps are nearly meaningless without a trap time/weight measurement to back them up.

Boost pwns you... 1500 dollar turbo setup for 250 hp or '3000'(id love to see a 3000 dollar 200 n/a build) for 200 hp.

[Ajax]

Okay, I can see where you're coming from, but its really a moot point. Its much easier to strap a car to a dyno and tweak things between runs than it is to run a car throught the traps, make adjustments, and do it again. That's why dynos exist.Breaking 200whp is not easy, but getting close isn't too hard, especially if you do all the work (competently) yourself. (200 isn't too bad if you run race gas)I don't know why you feel the need to continue arguing on this subject; this topic is about naturally aspirated KAs, not turboed KAs. I have a lot of respect for modern FI engines, but its not the point here.Good day.

[480sx]

You just said 'boost heads' was an insult and i thought id poke at you a bit for saying so. I realize that this topic is about N/A kas.. Thats why my posts are pretty much completely talking about the N/A ka besides what i said to you.

You got a link to your build thread? Id love to read about your FCW crank build. How about a dyno sheet? The only N/A fcw crank build i read about was in a mag, i bet its a blast to drive. Whats your redline?

[Ajax]

Gotcha.I don't have a thread for this particular build as my previous build turned out so horribly (I have a lawyer friend helping me to see if I can recover some of my losses from the first go round).I have paper dynos and no scanner, so I can't show you the graph. Its not just an FCW crank though, it is a stroked crank- now 2.6 liters. As I said previously, hoping for insight from Vin, it feels like its running out of air up top, so I really haven't bothered running it past 6500 or so. Throttle response is quite nice though, and should be even better once we figure out a decent intake option.

[480sx]

If your not going to fab one yourself check out Gato's IM. IMO excessive's is kinda a joke(very expensive one).. Pretty much every dyno sheet i have seen from them takes away all of the low/mid range a ka is great for and you get mild gains up top. From what i have seen a stock Ka's manifold is great(IMO the best) for anything less than 500 hp, however this is in turbocharged form. Im not really sure about N/A. The long runners creates a high velocity charge air which is going to be great for Tq.

I know what kit you have. IMO you need to rev that thing out to at least 8500 to get your moneys worth. Most people assume that because its a 'stroker' kit that it will lower the rev limit, however this isnt exactly true. With the beefy rods and only slight increase in stroke, the FCW crank almost demands that you rev it out. N/A power is all about revs.

[Bigvinnie]

Never said that dyno tuning itself was abstract, just the number that you were left with was.

Depends on the dyno.....I like to use the mustang dyno with the newest eddy program. Personally I find it to be pretty accurate and when you look at the cross over, it will try to calculate and more accurately detail where the true engine cross over should be at boreX stroke of an engine, (all engines rotate at different rates of speed so there is no way an engine truely has a cross over at 5200/5200 RPM).

Like I said 5200/5200 is a mathmatical formula but no engine do to engine displacement, BORE X STROKE will always fall at 5200/5200 cross over, all engines are different.

Now most dynos take a torque factor and multiply by it's RPM at 5200...My Torque numbers seem pretty realistic for how pig rich my engine was at it's given RPM, which ius less than a stock KA, changing K value with a 12:6.1 A/F ratio put my KA at peek power at a higher RPM, it's really a simple calculation. Changing K value using an N60 for an N62 MAF plug in showed my relative torque numbers....A KA can make peek power past 6000RPM, and I'm proof of it.

Theoretically dyno jets are over rated and inflate HP numbers, so do dyno paks. I like mustang dyno's because those systems inflate a larger degredation loss which would make it more realistic for real time driving conditions. Mustangs also use braking resistance to calculate those degredation losses.I find any other dyno on the market to be over rated, and for years the people that sell the hype that dyno jets and dynopaks are accurate are selling the use of this equipment themselves.

Sure there could be an over inflation of dyno numbers from dynop to dyno like at about 3% but how much does that really matter to call it abstract. BTW these A/Fr's are pretty accurate, I used an LM-1..

[Ajax]

I know what kit you have. IMO you need to rev that thing out to at least 8500 to get your moneys worth. Most people assume that because its a 'stroker' kit that it will lower the rev limit, however this isnt exactly true. With the beefy rods and only slight increase in stroke, the FCW crank almost demands that you rev it out. N/A power is all about revs.

I will once I get everything squared away. First it still needs to be tuned to Minnesota's 92 octane (currently tuned on Chicago 93 and using octane booster with every tank- its not a dd anyway now, so its not too expensive), but I figured why bother doing that before getting an intake manifold to really take advantage of the higher revs. Currently, the power still drops after 6500rpm or so- therefore not worth revving past it.

[480sx]

Sure there could be an over inflation of dyno numbers from dynop to dyno like at about 3% but how much does that really matter to call it abstract.

The difference between a dynojet and a mustang dyno is usually closer to 10-15 percent.

Ajax - Man that things gona be fun when you get it tuned. You'll walk some turbo hondas if you tune it out right. I have an article from a while back about a N/A ka hitting 300 hp @ 10k with a FCW crank.

[Bigvinnie]

The difference between a dynojet and a mustang dyno is usually closer to 10-15 percent.

That statement would of been true like 2 years ago....The newer eddy software is much more accurate.This one that I use actually shows HP and torque value numbers being less than what a dyno jet would show...Before tuning the SAFC and having all values at 0 my car made 153WHP on the dyno which seems pretty typical of most bolt on ka dyno charts I have looked at between mustang, dynojet, and dynapak . I was using 95 octane, most I have seen on dyno jets were typically 91 or 93 octane making the same power or close too it..... By far dyno jet inflates it's calculations by taking any remainder number and applying it to HP peak number.... A mustang dyno leaves remainder numbers constant. It just seems more realistic for a real world calculation.

[480sx]

Idk what your talking about really. Every time people compare dyno sheets(recently, this year) from mustang dynos to dynojets its a difference of about 10-15 percent. So maybe the software isnt as widely used or accepted as you think?

Its a widely known fact that dynojets give you feel good numbers, while the mustang dyno is the heart breaker. The later usually being closer to real world numbers.

Most dyno op's are not going to shell out big money for a later software version when their version works fine.

[Bigvinnie]

Its a widely known fact that dynojets give you feel good numbers, while the mustang dyno is the heart breaker. The later usually being closer to real world numbers.

Most dyno op's are not going to shell out big money for a later software version when their version works fine.

Exactly my point... If I saw higher feel good numbers from DYNO JET such as higher peak HP numbers wouldn't I feel satisfified with these numbers since I paid top dollar for them???Case in point.Not every dyno shop that uses the eddy mustang dyno has the most recent software to date, some to say the least that the dyno hp numbers could look less and somewhat disappointing to waht you could see on a dyno jet.......

So if that is the point I should feel really happy to assume that if I show figures of 161.9 HP on a mustang dyno then I should feel extra happy to see inflated happy numbers of 165 or better on a dyno jet... Reality is I like to see those losses in HP on a mustang, it's more realistic IMO... Even if you are in a dyno room with a temprature at roughly 70* F (ambient air temp for intake), have a degredation calculation figured at for most 4 cylinder engines and breaking resistance applied to the rollers, I feel that those numbers are more accurately described to what most dyno jets have to offer.

On another topic I spoke to Brian Crower again this year at fomula drift, about his KA24de stroker kit...

Now he told me that this stroker kit revs to 9000RPM/Redline due to changes in piston pin location and adjustment to placemet of piston rings. The longer stroking crank also provides a shorter rod.... These adjustments made to this stroker are what infact allow for higher rev than stock. What increases crank revolution speed is a lighter chromolly crank shaft which would make the KA engine much more rev happy than what the stock crank has to offer.

Majority of the problem with KA napsz engines is pin and ring land position which causes frictional losses, at high RPM causing HP loss and eventually fried rings, which is apparrently the case with GT3 KA's which have a life span of about 100 HOURS, using all OEM modified internals, and only make peek rev to about 8000RPM/redline.

Brian Crower told me out of 20 of these kits he produced for the KA there are only 3 left for sale...

[liquid_cool]

i was looking at this exact kit from BC..has lots of potential for N/A now with a T build later on..the kit does change the dynamics of the crankshaft a whole bunch..and is fully balanced as a total set...at its current $3000. its unobtainable for most thou looking to build a N/A ka..$3000. can easly pay for a turbo..or even a better swap.

[Ajax]

All good info. The only problem is that in application, the engine power dropped dramatically after 6000rpm. And I think its a function of such long intake runners. Sadly, its a game of money for me, as I have no fabrication skills and limited mechanical knowledge (other than some theory stuff).Come spring, I will have the money to do some testing, and hopefully I'll be able to realize the potential that is in this stroker kit.

[Bigvinnie]

All good info. The only problem is that in application, the engine power dropped dramatically after 6000rpm. And I think its a function of such long intake runners.

Nope it's not the intake runners at all. It's the MAF you use...

Let me try to simplify in laymens terms..........

You want long runners for vacuum, and velocity. In a state of high rev longer is better, as velocity will only increase down the runner length the longer it is.

Now you can look at instances with Honda were there is a designesd skunk 2 manifold specifically for Honda B,D and H series engines. The runners are increased in length for higher rev and velocity... But it only makes the engine more top end and high rev.....

A KA24de manifold is a curved long runner manifold that is desigend for midrange and high HP numbers.....A curved runner, rather than a straight runner will only help torque and midrange HP numbers. Reason being is that if you use straight runners there is no direct choke hold on flow, flow is evenly dispersed through the diameter of the runner, and it travels at a equally travelled rate to what the engine demands which is great for high rev. A curved runner actually makes it harder to produce maximum flow since in a curved design for air is now constantly changing direction, you get some what of a dense build up along curved dimensions of runner walls rather than straight dimensions of runner walls. Anythiong that impeads on flow is restrictive which density plays a matter in this and causes a curved wall runner to have higher velocity rates of speed at lower RPM's, than what a straight runner can do which is maxing out velocity at high RPM's....

The problem is the MAF, and your CAS and K values.... Effectively the objective is to change how the ecu percives it's load value....With a larger MAF, that can use a larger spectrum or use of voltage, you shift the K value over. A larger MAF slows velocity, takes longer to cool a hot wire, so there for it will trigger theh ecu to say that the K value is under less load. This will actually advance timing in higher parts of the RPM range that you normally don't see using the stock G60 or G70 MAF...


Modified by Bigvinnie at 6:15 AM 9/16/2008

[Ajax]

What MAF would you recommend then? And what are you using to tune? I'm currently running a JWT ECU with AFC NEO assistance.

[Bigvinnie]

What MAF would you recommend then? And what are you using to tune? I'm currently running a JWT ECU with AFC NEO assistance.

For an NA/KA an N60MAF will do fine. It comes from the 89-94 nissan Maxima's and was also used on some infinti model cars.You can use the 2in, 5out value with SAFC that the N62 MAF uses which will drop A/Fr'into pig rich, (this isusing the N60 MAF with the N62 settings). But it will set the K value so far that timing will advance further than what you would normally see it.

You can also use the 4 in/5out settings designated for the N60MAF using the N60. If you are using a JWT tune already you will just want to set the SAFC across the board of it's RPM range at +10, since if you left settings at 0 correction for fuel it would run a tad lean since the diameter of the MAF is larger and there is decreased velocity passing by the hot wire. You will want to start your NE points at 2800 RPM and set the points as far as 7000RPM. This will allow for more correction to your theoretical pulse width making your tuning of the SAFC more accurate through out that RPM range. With an SAFC your objective is to cram NE points as close together to each other which would improve correction of (TP) theoretical pulse width.K value would already be detrmined by intake velocioty to hot wire so typically your just making adjustment to injector duty cycle...

[Ajax]

Thanks! Probably won't get around to everything before storing for winter, but this will all help for next driving season.

[Truck]

I have a question. BigVinnie, what is up with that huge torque dive from 2700-3800? Is that a factory tune for economy?How can you get that power back? Could you use some tuning device, like perhaps a fuel and ignition computer? or maybe a wideband? I suppose JWT ecu will get you that horsepower back.I don't know much about tuning, except maybe some names and devices.

[Bigvinnie]

I have a question. BigVinnie, what is up with that huge torque dive from 2700-3800? Is that a factory tune for economy?How can you get that power back? Could you use some tuning device, like perhaps a fuel and ignition computer? or maybe a wideband? I suppose JWT ecu will get you that horsepower back.I don't know much about tuning, except maybe some names and devices.

The torque dive was obviously something that couldn't be tuned with the settings that I used on the SAFC.

The setting I used changed the K value, but ultimately an safc doesn't change or adjust ignition, only fuel through (theoretical pulsewidth).No matter what adjustments were made to fuel, it was too rich for the timing that was selected by the K value. It's not really that much of a bumber, the HP is so much more of a linear feeling the torque band doesn't matter that much.

[sav180]

now with an excessive intake mani with bigger inj like sr370 you would still increase the fuel out put or no??

[sav180]

...

[Ajax]

You'd probably want to hook up a wideband to see if you actually need bigger injectors. Stock KA injectors, from what I've heard, should be good up to @200-220 hp- but don't quote me on that...

[Bigvinnie]

You'd probably want to hook up a wideband to see if you actually need bigger injectors. Stock KA injectors, from what I've heard, should be good up to @200-220 hp- but don't quote me on that...

I actually maxed out my stock 270cc injectors at 162 WHP. That would be 98% of the injector duty cycle. So that would be about 205 Crank HP or relative to it.

I've already blown injector 2 and injector 4, it's obviously time to upgrade to 370cc sr20det injectors. Then fuel pressure will need to increase by 10PSI. Then looking to achieve 190 + whp with a PDM cam upgrade and stock 9.5:1 compression ratio.

I wanted to get some custom RC injectors for a better spray pattern, but I simply can't afford it.

[Ajax]

That would seem to make sense- 162whp would be somewhere in the 200bhp range.Strange though, as AMS dialed back my fuel when tuning, and I'm still on stock injectors. I'll have to look into bigger injectors once I'm done setting up the chassis this winter.

[Gabes13]

this thread is full of win

[Bigvinnie]

That would seem to make sense- 162whp would be somewhere in the 200bhp range.Strange though, as AMS dialed back my fuel when tuning, and I'm still on stock injectors. I'll have to look into bigger injectors once I'm done setting up the chassis this winter.

It's crazy how much fuel the KA demands after 6300RPM. I literally had my safc NE points set within that range 6200~6600RPM, and correction was at +50%. I maxed the injectors just to get that extra rev range without getting the HP/RPM drop off.Truth is base timing was at stock 20btdc, and A/Fr's were at 12.6:1 which is perfect for scavaging and making big numbers at high RPM. I could of actually advanced the distributor a few degrees possibly maxed out at 166~167 WHP, but right now we will never know because I'm moving on to bigger upgrades as of right now.

Don't know why AMS would back off on the fuel for your engine unless ignition timing was retarded. Or your K value and fuel richness was just adjusted from the JWT tune, JWT tunes sometimes run a little to rich and hinder power.


Modified by Bigvinnie at 12:22 AM 11/20/2008

[Truck]

Ajax, I keep getting the impression that your stroked KA put down 175whp, but couldn't find the post that showed the dyno chart. Could you maybe link to that post?

If that is the case 40whp is impressive I think. Thats easily a 30% increase in HP. But maybe this was in conjunction with High comp and a built head+cams. Torque at idle probly went up 20 ft lbs, leaving you room to take some low end away for those high end cams. I know you are interested in a new manifold, and if your gut instinct tells you "ITB's" GO FOR IT!! I would keep building that 240 for a long time. However long it takes to get it done right.