[LotusElise]

Full K20A Type R swap stock block
RSP Manifold opened up to 70mm
S90 70mm throttle body
Custom chopped up Iceman plastic cold air intake with vibrant 3.5" velocity stack and filter. 3-3.5"
K-tuned fuel rail, intake manifold gasket
PLM 4-1 reverse megaphone 2.5" v-band header
Custom 3" piping with vibrant resonator and muffler
RDX injectors
Hondata KPRO

Tuned at churches
250whp
184ftlbs torque

The lower number is the smaller upper part of the intake I was using 2.5-3" tapered with Greddy filter.

I just read this some day old lines above...

Did I get you right...swapping from a tapered 2.5-3" Air Intake to a 3-3.5" one with a velocity stack creats up to 10 ftlb's? Both setup's are fine tuned? Unbelievable...maybe I have to change my church to find my churches-believing :wink:

But seriously, would be interesting to know what was happend there...thanks

 

[LotusElise]

Previous K20 motor - http://www.k20a.org/forum/showpost.php?p=1782999&postcount=736

to K24/K20 stock bottom


Details at http://www.k20a.org/forum/showpost.php?p=2153369&postcount=510

Wow...that torque line looks very different for a 600 cm³/cylinder-block on full load: a lack of torque between 4750/min and 5600/min, after that back to business with a +40 ftlb step in between 600 rpm? Did you already take it's temperature :wink:...sorry, but for me it seems to be the engine is pretty restricted doing it's work, like it caughes or sneezes.

May I ask, what (VTC, VTEC, Load, Measurement technique, temp., ...) happened there? It (the engine) need medicine, my lord...

 

[LotusElise]

Stock K20A
Kpro with an e-tune (94 octane pump with 10% ethanol)
Filter directly on the TB
RBC intake manifold with hondata gasket
RDX injectors
ASP header, 2.5" high flow cat and an old school 2.25" DC Sports exhaust

I'd really like to fix the huge power dip at 5k, it's very apparent in street driving too. All in the tune? Tuner seems to think it's all from the quiet/restrictive exhaust, but I'm not sure I want something loud....
VTEC set to 3100rpm high load.

Interessting torque curve. Could you show the following full load graphs for a help:

1. AFR over rpm
2. CAM and CAMCMD over rpm
3. Ignition over rpm
4. K.Count over rpm

It seems to be an oscillating induced dip, but to figure it out the analyse of the above is necessary...it may not a problem of the exhaust...but we will see.

Could you provide these graphs?

 

[LotusElise]

Hey man!
Here's what I know how to do with K Manger, not sure if there's a better way to show it....

Thanks for the data...

I just checked the picture (KManager analyze today evening) and as prspyder already mentioned, the AFR, the ignition, the CAM/CAMCMD and the K.Count looks in a the first approximation unobtrusive in the dip area from 4200 to 5800 rpm.

What says the analyze by now:

• As AFR seems to be in a good bandwidth, the fuel amount should be checked next
• big valve overlap in the dip area -> influence of both, intake and exhaust, extracting which one is the next step of analyze
• A flow oscillating problem, causing the dip and the low gain upper 5000 rpm, seems to be likely
• The typical gain (> 5000 rpm) from the header and the better exhaust is completely missed in the torque graph
• It is, by now, not clear which role is played by the used shortest short ram (filter directly mounted on the tb), but this is very fishy

Only guessing for the moment or betting ...I see two problems,

• the distance between filter and the runners of the intake manifold is to short,
• and something strange: untypical high low end torque (restriction helps) and also untypical low high end torque (restriction helps causing it)...the engine will say, it is pretty restricted concerning flow through it...but I would guess first CAT or MUFFLER ar not in order, then secondly it may to have a small diameter
  

 

[LotusElise]

Stock K20A...
...I'd really like to fix the huge power dip at 5k, it's very apparent in street driving too. All in the tune? Tuner seems to think it's all from the quiet/restrictive exhaust, but I'm not sure I want something loud....
VTEC set to 3100rpm high load.

Hi Run Away,

your calibration is pretty pretty interessting...thanks for the chance to analyze it!

Summarize calibration and datalog:

• K.Controls reduces the ignition advance from 5000 rpm to redline by around 3°...but retarding will not solve the problem, as it is not the cause for sure
• OEM fuel injectors would perfect working at this power load...the RDX are pretty bored (60 % at redline)
• High speed fuel table for 50° advance shows clearly the indication of the power dip -> decrease of fueling by up to 20 %. In conjunction with the convenient AFR of around 12.5-12.8 we can conclude the volumetric efficiency decreases significantly in the rpm range from 3200 up to 6200 with a minimum at 5000 (s. also power graph)

Ok, nothing new, but now it is for sure: the engine has a really breathing problem in the rpm range from 3200 up to 6200 with a minimum at 5000 rpm.

What can be done to solve the problem?

FIRST Step - is it a backpressure problem?:

1. I would recommend two things for a test...the raise the VTEC point
2. in conjunction with a retarding of VTC at high and low speed cam...and dyno once again (if there is backpressure, reduce overlap and raise VTEC!)
3. check the conditions of the CAT and the Muffler concerning restrictive particles or damages
4. check for leakage, especially at the lambda probe area -> two guys, one to durn the muffler, the other one for sniffling

SECOND Step - is it a intake problem?:

1. Test different intake pipes (the pipe before tb) lengthes
2. dyno every one on street -> check the AFR change in that dip range

Answering this two questions will help you to find a solution for the power dip!

Normally if the something is restrictive in the engine, you will see it when rpm and load raises...here we see a big breathing problem in a specific rpm range far away from redline, which leads to the suggestion it is a combined problem of restriction and oscillating, both causing a decreased volumetric efficiency. I believe the oscillating problem is to solve first, the other one is a project for the future

 

[LotusElise]

Just had my car tuned on VP C85. Here's the graph showing my original pump 94 vs C85. I'm happy with the gains but curious as to why they were only made up top, any ideas?

Also with the C85 tune I switched to a 4" intake from a 3" if that matters.

View attachment 58802

As VP C85 is claimed to be up to over E85 (by VP racing of course ) it could look like this fuel comparison there...looks very similar to your graph.

BUT, as ignition tuning is one of the most diffuse tuning tasks it completely depends up to the ear of the Tuner and the boundary conditions together with the effectivness of the Anti-Knock-System...I would say, the gains shown in your tune are coming from a more focused work of the tuner in the high cam area (ignition and fuel), a bit better vaporization of VP C85 (= better cooling of charge -> take a look in your fuel table, should be increased, look at the AFR, should be more smooth because of the intensed focus) and the lower intake pressure drop due to the 4" intake.

DOUBLE BUT, The data log together with the cal.-file of the best runs of both can clearify this much better as every suspicion

 

[LotusElise]

depends on the trans if it is a 6th gears you will use 4th it if is 5thgears you will use 3th is necessary to use the closet ratio to 1.00.

That's right :up:, if it is a ASU5-tranny ([email protected]th gear), coming with the K24A2. The other 6-speed-trannies, coming with K20A/A2, are more close to a gear ratio of 1.0 in the 5th gear (0.972/0.921 compared to 1.212/1.147 (exception K20A with RBC3-Tranny)).

In addition:
Actually it depends an a lot more properties...only to name one of it, the AFR reading dead-, response- and output time together with it's accuracy of +-0.6 points...inertia dyno is a challenging thing concerning the right gear ratio due to requirement of measurement techniques and transient operation functions to get the right tune and measurement accuracy! Following that for a 6-speed-tranny, a 3rd gear pull has some disadvantages due to e.g. the AFR reading concerns vs. a 4th gear pull. A 5th gear pull would only from a stand point of measurement advisable not from a stand point of the security in the dyno room and the higher stress in engine and tranny. Concluding for Honda's 6-speed-trannies: 4th gear (or even lower if your measurement technique and engine transient functions are fast enough) :up:

 

[LotusElise]

Wow...pretty impressing torque curve. There is some...not to say huge...potential in the mid range left ;-).

Some question to your work:

• Do you use a K24 head or a K20?
• The header is a 4-1 system? Which pipe length (head to merger)?
• How long is the intake before TB?
• How long are the runners of the GATO intake manifold? Which diameter?
• Fully tuned or only beyond 5000 rpm?

I will appreciate any info about the above...maybe a photo of the enginebay, as the dip can be caused by a wrong VTC, a to short intake, inefficient header/exhaust, wrong timed cam, only 25° VTC...and some other causes...to point at the intake as a cause for that dip with that info is a risk , as torque starts good and in that dip area should be able to lifted up by advancing the VTC system...like in the range beyond 5000+ rpm, which also need some advancing (stage 2 cams need not as much as OEM ones of that) until it should be retarded, when the inlet valve closes to early for the reflected pressure wave...so, I will wait for more info to be more able to clarify that dip.

Anyway a lot of work went in that project, with a few more it should be possible to release all that potential which slumber in there...:up:

 

[LotusElise]

alexEF,

thanks for the info...

Do you use a K24 head or a K20?
It is port and polished K24 head

Ok, I understand, so you win up to of valve lift more flow to reach or overtake the K20A-cyl.-head-flow values...

The header is a 4-1 system? Which pipe length (head to merger)?
Yes it is ASP 4-1 budget header. I dont have much info. like the pipe length but i can measure it tonight. Here is the thread where the discussion on the budget header group buy http://www.k20a.org/forum/showthread.php?t=124554

Is it this one?

How long is the intake before TB?
based in the Vibrant website;
Tube OD: 3.5"
CLR: 4.5"
Leg Length: 2.5"

Sorry, I don't know the acronym CLR. Could you please write it out?

How long are the runners of the GATO intake manifold? Which diameter?
i need to measure it. it is 90mm

Woooohuuuuu...that's stark, man! You meant lenght, didn't you? So you only want to drag race? Or want to do any other high reving performance?

We used 50deg vtc. This engine will see a step-by-step upgrade since it is a budget build and that is the reason i bought the 90mm IM. My next plan is 14:1 piston or higher and stage 4.5 cams but that will happen after 3-4 months.

A CR of 14:1 or higher means you will run some high octane (100+), highly oxygenated fuel...will be a must to prevent knock if you want to it for more power as now. I am really interessted in your goal for that engine.
As a thumb value: for any NA K20 premium fuel using race engine, revving in the range between 4-9 krpm, I wouldn't go higher as 13:1, as beyond that, due necessary ignition retard (to prevent from knock), power decreases. So there is a must for higher octane fuel to stick on the MBT (max. or mean best torque at a certain load and rpm) driven ignition advance.

So, my impression is (the planed CR of 14:1, Stage 4 cams, 90 mm Runner length, and so on), if you are going to build a drag racer, the dip below 5 krpm doesn't really matter, so we should focus on the rpm range for shifting...approx. from 5-8(+) krpm.

My question to you: what is your goal with that development? I only want to understand to be able to help you further.

Thanks for reading...

 

[LotusElise]

alexEF,

...i will put back the original engine in the rsx and will participate in local road racing (restricted to 2.0)

Pretty interesting...which character of road does it mean? Strong hillclimbing, roughly flat track or a mix of it? I am asking, because in case of hillclimbing I would choose a intake supporting a Md,max at around 0,8 x rpm @ redline and in the case of a flat peaking at 90 % of redline rpm...

...while the 2.4 will be in drag. once the 2.4 is in the ef, 14:1, 3" exhaust and etc. will follow.

If you go with stage for cams, I don't believe a VTC of 50° is necessary, as the valve overlap is so big that a max. advance of 40° or lower will be sufficient enough. A wise man once said: "...the engine is like an air pump...", therefore also here tuned lenghtes and diameters of intake and exhaust (manifolds first) will have a big influence in the alternation of load, consequently in the power curve (shape and height). McCarthy did a great job concerning the exhaust investigation, one of his results was:

• if it powers a 2.0 liter, it powers also a 2.something
• the shorter the primaries and secondaries, the more the engine get happy (there is of course a limit )
• he recommended 4-2-1 systems, as it is a bit lighter and gives roughly the same power as a 4-1 system
• ...ööööhhhhaaa

maybe it is better to swap to a new build thread, as this no more of result presentation? What do you think?

 

[LotusElise]

does anyone have a tune to share for my mods or something close?

RSX type s/ k20a2

RRC
skunk2 alpha header
thermal 3" catback
SRI with velocity stack

Hondata KPro emulator?
If yes, what about the RSX tune with the Toda header from the list of tuned maps of the KManager? It wood be a good map to start the lambda tuning...VTEC and VTC also could be done for a first approximation on street. If you need help, let me know it...

 

[LotusElise]

K20A2
3.5" 2 piece intake to BPI Velocity Stack
3" Exhaust
PRB IM
Hondata IMG
No Name Header

Was wondering shouldn't my torque numbers be a lot lower?

KuBurd, for a PRB IM and that setup pretty good torque . Is this measured at wheel base or calculated for flywheel base?

Not having seen the VTC and ignition timing map, but peak power, as Mozz already did comment, is pretty early, even for a PRB IM.

• Have you a picture of the header?
• If you don't mind please post the VTC and ignition timing map
• Could you please share the measurements of the intake (TB, CAI, Filterdesign and a pic of position of it)?
• could you please share more details about muffler and CAT?

I would appreciate to learn more about your setup and engine, as this dyno graph is very interesting.

Thanks

 

[LotusElise]

Thanks for the pictures :up:...I see there a steering servo pump. Is this a pump system with a pressure contolled bypass for oil pressure control? I appreciate any info to that...

This is whp. Has stock TB, no cat, thermal 3" exhaust, and car has power steering. Header is welded on 3" piping all the way back to the only flange I have by the exhaust.

Thanks. What kind of muffler is there mounted?

20" of 3.5" 2 piece intake piping to a VS out the spare headlights I hacked up.

Pretty nice piece. No filter or only for picture you made it naked?

If I get more time tomorrow or sometime this week I'll post up the vtc and ignition map because it is freezing outside.

:up:

I would put on an RBC or better IM but I have EKK1 mounts so it gives no room. Just don't really feel like mounting the radiator elsewhere.

If clearance is of an issue in the enginebay may you take a RSP manifold (there is still one for sale in hear), it has about 26 mm more of clearance compared to a RBC or RRC (both are in a range of 275 mm against 249 mm of the RSP). The RSP has a big potential over the PRC, for most setups it powers in the range of a RRC but with a much better clearance consumption .

The way the power flattens out at ~7300rpms is an indication of the TB beginning to choke. If you go check your datalogs you will see the engine starting to pull vaccum at over 7000rpms.

:up:...I also would like to see it.

Anyway I know e.g. a 250 whp K20 engine with a stock TB, running in a ralley series car (stock RSP IM, custom short ram intake, 12.5 CR, cams with higher lift and some more duration, adapted valve train, custom 4-2-1 header). Out of that and other observations, the TB is a, but not a major bottleneck for power, the more bigger part in that game is played by the oszillating intake and outtake gas mass...because of that, I believe with KuBurd's kind of setup there could be learned alot . To open that door for KuBurd's setup will be a pretty interesting task...if there is a interest :wink:

 

[LotusElise]

Thanks daje, pretty nice examination and proving of every engine has due to it's mods and it's specific fitness to be tuned individually :up:

05 RSX Type S

MODS:
Generic 2.5 inch SRI
Hondata Reflash (RH and regular)
Stock piping with hi flow resonator, vibrant Muffler
Megan shitty short header.

...Blue Line = Non RH reflash with shorty header and test pipe
Red Line = RH reflash with Shorty Header and test pipe
Green Line = RH reflash with Invidia RH
I picked up 25whp from 5k-8k and around 20ft-lbs in the mid range. Invidia FTW...

The graph below is the best pulls from each of the 3 combinations above:

Do you have a picture of your header? I just search for "Megan shitty shorty" but didn't found something adequate (just pics of Megan Fox in shorties, don't know the situation inside of that shorties).

Anyway, 150 ftlb's at wheel up to 7 krpm with your setup (2,5" short ram intake, short header maybe like the one of the stock K20A?, individual tune) is a blast :wow:

 

[LotusElise]

Thanks CHILD for sharing, very interesting setup :up:

...246whp @7000rpm

May my calculations were wrong, from that the dyno should ends at 6.75 krpm, when I transform 98 mph into rpm . Do you have a ASU5 (stock K24A2) tranny?

Only change was open header. Same Dynojet, same mods as above. The car wasn't revved to redline on this pull since this was done as a favor to see if there was a worthwhile change in power from dropping the exhaust, and my tuner JTran, didn't want to stress my engine just to cure my curiosity. None of us expecting this large of a power gain on a stock longblock k24a2 on 93 pump gas. No porting done anywhere besides the TB opening. Stock runners, stock plenum, stock head, blah blah blah.

Don't mind at all, that's typical for K24A2, power blocks at around 5.5 krpm until the bottleneck is opened. One key is the exhaust side, the intake side you already opened...it's like to charge a open door .

But please keep in mind the following, tuning allways has to be done some rpm's beyond the setpoint redline for save driving. So lift redline for tuning and reduce it afterwords for custom operation, as wrong shift and other failures could bring the engine in a tight spot :wink:. So "stress on the engine" during the tuning is for to save customers favour! For a stock K24A2 I would suggest 7.25 krpm for tuning and 7 krpm for daily redline...as a conservative setpoint. :twocents:

 

[LotusElise]

CHILD, thanks for the background infor to your setup up and tune :up:

... "there's no way a stock K24a2 can make 250whp without head work or cams"...

You easily can disprove those guys, if any other OEM cam is allowed see this: http://www.k20a.org/forum/showpost.php?p=2706290&postcount=67. 16 whp above that magic limit and below 7.5 krpm

 

[LotusElise]

What can you all describe from this dyno chart? is that normal range power and torque of k20a cl7r engine...

Regarding the quality of the torque graph: the VTEC engagement and the post 6.5 krpm torque gradient the engine seems to be pretty restricted. Concerning the quantity of the torque graph: for 11 g/m³ water load of the dry air combinde with fuel quality of RON 97 the ignition timing is maybe a bit retarded, as the combustion velocity suffers due to water dissoziation...but 190 Nm or about 140 ftlb for the low speed area are pretty good (this area isn't that much affected by scavenging problems as the high speed area)...so I have to conclude, you have a very good basis , but your engine pretty much suffers due too breathing restrictions.


As I stated in the introduction thread, your setup has a big potential...intake manifold, compression ratio, head (ported by an expert?) and injectors could do more work, but maybe the intake piping form, the valve timing (camshaft's) and the exhaust are damp that will.

So your plans to open that bottleneck by other cams would help, but the problem would be there anyway...biiiig potential to better the scavenging phase

 

[LotusElise]

Re: love 24

...Love24 is a prefect ayurvedic supplement contains capsules and a dietary medicine for all the physical problems within human body....

Should I feed my engine with it?! LOL

 

[LotusElise]

05 k24a2 stock bottom end
02 k20a2 head (stock ports)
k20a2 oil pump
prayoonto 4 cams with 25* vtc
supertech valve springs
ASP hood exit header
RRC intake manifold
Hybrid Racing 70mm throttle body
4" intake with 7-4" velocity stack
C85
272whp and 184ft/lbs torque

Was really hoping to make over 280 but I'll settle for 272. Tuner said if I kept the 50* that would've been enough to make around 280 but I wanted to play it safe and went with the 25*.

Next upgrade I think is to go for a center feed intake manifold with bigger throttle body. Any suggestions?

View attachment 69506

Just some thoughts.

Small steps forward to test...

• intake with 3" and one with 3.5" (length > 250 mm, if possible)
• ENDYNE or ...ported RRC
• balance the tuning by 4 individual temperature or lambda probes in the header, sometimes more advancing is possible
• 9.0 McCarthy intake manifold

bigger steps forward...

• higher static compression to utilize the cams potential, as the loss of dynamic compression with that long duration is significant!
• those higher CR pistons should have deep valve pokets to gain more midrange and to better the VTEC transition...the pistions should have a combustion velocity enhancing machining
• try to realize a more farer position of the injectors to get better vaporiziation of the fuel and more cooling for more advance of ignition timing and a higher density...a 2nd line makes it easier to build up a two fuel system (E85 and pump gas)

Anyway, I think the use of Prayoonto 4 over 2 with that low CR isn't worth to use for a daily driver or even a circuit racer, as the torque lost in the midrange through the VTC lost of 25°! costs you about 10 lbft somewhere around 5-6.5 krpm...the win of stage 4 is in engine speed range (> 7.5 krmp), where the stock K24 shouldn't be for too long time.

I don't understand how your tuner can squeeze out more high end torque (net power beyond 7 krpm) with a 50 VTC cam gear?! In that area VTC > 25° aren't in use with a stage 4...the benefit of higher VTC's is in the area from VTEC till somewhere around 6.5-7 krpm...may he uses other techniques :boxing: to tune, like the VTEC transition dip ?! Sorry, but I don't think that tune is worked out as it could be.

 

[LotusElise]

...I remember him saying that I won't feel it though.

...because the tuned VTEC transition isn't there . Of course you can feel it if you have both, before and after. In the 6th gear it will be nearly a second of a 11 ftlb dip. You will miss it, if you know it .

The problem of these Honda iVTEC technique is the rotation of the cam phase (VTC) needs about 100 ms/10°. In between a cam lobe this is fast enough. The problem awake when VTEC transition is needed because:

• high speed lobe mostly needs a more advanced cam when it chime in compared to the last VTC angle of the low speed lobe
• high speed torque line is very sensitive to the VTC angle, so if not the right angle is already reached, you get a torque dip as long the cam turns to the right angle

Consequently, tuners turn in the high speed cam [email protected] before VTEC is activated. E.g. last low speed cam VTC angle before VTEC is 20°, first high speed cam VTC angle after VTEC point is 50°...this means 300 ms to turn in, but VTEC is immediately activated. The solution is to turn in the 50° VTC angle before VTEC, where the torque sensitivity isn't that high as in the high speed cam. So the tuner advance in the low speed phase the VTC angle to 50° in that way, that after VTEC point the cam is already at 50°.

If the tuner is lazy, he just finished his work...the customer gets a engine back with a dip. Why? VE gets low because of the not ideal VTC angle there, consequently air-fuel gets rich before VTEC point, directly after VTEC the VE is significantly higher, fuel and ignition timing are already tuned. But the runner walls are still fuel wet from the area before VTEC point, if not right tuned, this 50° area will also get temporaly (some 100 rpm's) rich...


...that 10-13 ftlb dip in your graph just need some more tuning, that's all.