Hybrid silvertop/blacktop better than silvertop ?

[yolk]

Hi all,
Quite new here and found this site by accident it's good to see the 4A spirit alive and kicking in New Zealand.

What interest me was the talk regarding silvertop vs blacktop especially regarding intake air velocity,the cams,the throttle bodies etc etc .. in fact i started my car off with the silvertop but felt the throttle response was not what I expected and plus the fact of wanting to hear the sound of the 4 throttle open induction started me on my quest to convert my enginet to a blacktop .. or in it's current stage a semi blacktop .. here's what done to my engine so far

1. started off with a late model silvertop (the one with the teardrop shaped inlet manifold) and c56 g/box
2. got hold of a complete blacktop head and throttle bodies and plenum
3. got hold of a complete 6 speed ecu and wiring
4. installed the head together with the wiring and ecu
5. engine was eating black oil like mad
6. stripped the engine and changed piston rings and at the same time overhaul the head ie change valve seals etc etc
7. fix everything back and so far the engine is running fine with visits to 8krpm on a daily basis
8. because my ambient temperature is around 34-35C degree installed an oil cooler as well
9. full set apexi N1 exhaust with the stock 20v extractor




The car that is being compared to is a silvertop with has been freshly rebuilt as well with hks/fgk 4-2-1 extractor along with apexi n1 exhaust system as well as a tom's carbon fiber induction box. The only difference is he is running the stock airbox with K&N drop in filter where else I'm running HKS open pod filter with no heat shield. We are also quite suprised with the results and has left us stumped. Both the engines are in the same body ae101 sedan (ae102 in US i think). Forgot to mention that my car is the one in orange and my friends silvertop is the one in blue. We thought my car would do badly because I'm still running silvertop pistons and now since I'm running open combustion chamber the power should be even worst not forgetting with the larger throttle bodies and also larger plenum.

Now pls do go and start asking why would I want to change to blacktop wiring instead of just installing a full management and get much better power gains. There are not many people who are playing around with the 20v around here and most of them are into V-TEC's and that leaves us poor 20v owners with empty promises by tuners and some even dared to take on their offer and install a haltech on their 20v and the results are not that promising so some us had resorted to making the full use of OEM ecu's but I will be installing a full management setup in the near future and hopefully will learn to start tuning the car myself. Anyway let's get back to the matter at hand which is the blacktop vs the silvertop vs my hybrid 20v

[Blkwinter]

It looks like your hybrid engine performs the same as the silvertop?

[NZ_AE86]

So, if I am reading it right then you car with a bigger intake and exhaust yet lower comp ratio make more power up top and less down low? If I am reading it right then this is what you would expect! Or am I missing the point??

But good to see someone trying to get more out of a 20V, they are not a well designed head, good swirl is very hard to achieve. You may also find that your friends car is suffering from shit fuel and as yours has a lower comp ratio it is much happier on NZ's crap fuel.

[vvega]

only need swirl for midrange
top end its era;avant

v

[yolk]

Blkwinter,
almost the same but my setup is giving me slightly more power especially after 2.4-2.6k but the point is with my mismatched setup and my silvertop piston which was not designed/meant for the open combustion chamber plus the fact now i've much lesser squish area as well

NZ_AE86,
actually my dyno is the orange/red one and his is the blue one if you notice my car is making better power/torque from 2.4-2.6k onwards compared to his and we're both running RON 97 which is what we can get locally.

[NZ_AE86]

Blkwinter,

NZ_AE86,
actually my dyno is the orange/red one and his is the blue one if you notice my car is making better power/torque from 2.4-2.6k onwards compared to his and we're both running RON 93 which is what we can get locally.

Yeah, thats what I said! Yours will make more power up high. You have more air due to your intake and bigger valve lift as well! This is what I would expect to see.

[NZ_AE86]

only need swirl for midrange
top end its era;avant

v

True, that part was not in ref. to the dyno just a random comment!!

[yolk]

actually my question really is that we all know the plenum is way to big for a 1.6 litter NA, so is the throttle bodies, not forgetting the intake/exhaust ports as well if this is the case then how and why is my engine making more power compared to the silvertop ? since i'm running lower compression as well as loosing the squish area which is available on the silvertop

[NZ_AE86]

I hear what your saying but, you will have lower comp, but this and your big ports/throttle bodies will have a low air velocity but high flow so you should expect to lose low end torque but due to your slightly higher lift cams combined with you large intake system will give you a little more up high. As your dynosheet proves.

[Silvertop]

yolk - Nice post. Good read.

Where were those power figures taken from? Hub / wheels etc...

[yolk]

Hi Silvertop,
Just trying stuff out on the 20v with whatever resources available locally. The dyno is at the wheels figures. Though the difference of peak hp between my hybrid and the silvertop is not much about 4hp only but what's interesting is what happens down below on the hp/torque curve. Another friend of mine with an almost stock blacktop will be heading to the same dyno shop soon and we'll compare the reading to see what he gets. The dyno's were done with RON 97 fuel

[RedMist]

I don't think you will be running lower than 10.5:1 compression. If you CC the combustion chamber I'm sure you'll find the blacktop and silvertop very close in size.
My bet for mid end increase is still exhaust. The stock 20 valve exhaust is very good and don't forget that you have dramatically larger exhaust ports.
It's a minor increase that's hard to judge on a dyno. It could be down to engine temp or slight changes in atmospheric conditions. I'd rate the fact that your car is faster, much more than I'd rate the dyno readouts.

The suprise in your dyno readouts is how closly the silvertop and your blacktop hybrid follow each other. I would have expected quite a difference considering the flow and design changes between the two heads.

[yolk]

RedMist,
I was thinking the same as well since like you mentioned the flow and design changes in the head is different the results should reflect the difference as well.

BTW here is the dyno of his car and my car with AFR.