mattxx

Just wanted to pick the local guys' brains for opinions/knowledge on Comptech Supercharger (w/ Aftercooler) pulley upgrades.

Basically I'm possibly in the market for a boost upgrade but do not want to cross the threshold where I would need EMS, injectors, etc.
According to my research, it is safe to upgrade from 5 to 7 PSI without needing bigger injectors and without changing timing.
On a CT kit, a 4.0" pulley will net 7 psi. Does anyone know where I can get one fast? I'm changing out my belt because its sqeaking (I think) and want to go ahead and change the pulley out.

Also, what is the preferred belt brand here in the UK? In the states, performance enthusiasts prefer Michelin Gatorback belts because of its strength and grippy surface.
I picked up a Gates belt that is 2mm over what I need at a local Central Auto Supplies. Thoughts?

I have a wideband an understand I will need to mechanically adjust fuel upon raising boost.

Cheers!

MB

Hi Matt, Dixon at DMS is a comptech dealer I think. Or join up and post a wtb.

s2konroids

If you bear with me i will explain, i don't post so much nowadays as people a) some people on here talk shite/don't believe me, b) I cannot be bothered arguing with people when i've proved people wrong in the past, so i more or less gave up but i will give you some good info which is not made up and is based on sound knowledge/my findings.

You can get away with a 7psi pulley on stock injectors, and one bolt on, maybe two - but that's subjective, no two cars are the same.

The problem you have when in boost is you need to run at an acceptable AFR, typically in the low 12's (e.g 12.1 ~12.3). Now am i correct in thinking you are just using the comptech box (ie map clamp box) and you are 'aftercooled'?, if so all this CT box does is clamp the voltage that the Map sensor see's. If the map sensor see's above a particular voltage (psi/kpa correlating with boost) the ECU will literally freak out, so in essence this device hides boost. Unfortunately you have a couple of problems...

1. By clamping the map sensor voltage you are effectively significantly reducing the threshold for the stock ecu to do adjustments in weather and altitudes etc.

2. This device does no tuning what so ever, so you are relying on the FPR to get the AFR in line.

3. You will be using the CT FPR, folk have said this alters the injector duty cycle - no it doesn't, it simply forces more fuel through thus enrich the mixture based on when the injectors are opening. Now at the bottom of the rev range you will run pig rich due to the differences in the stock honda fpr idling rate vs the CT fpr, you will typically run in mid 10's which is awful for making power, then run lean at vtec and beyond - you enrich the mixture by turning up the FPR at idle - typically in the 60-70psi range, unfortunately right at the top end you will be running near 100psi - not ideal TBH but not completely dangerous, still i wouldn't personally like this range.

By design when you get to @8200rpm the map will run pig rich again (~11 AFR), again not good for power.

4. You can get away somewhat with 5psi with no retarding of ignition timing, but still the car may pull a little timing - not ideal. With 5psi you would be roughly be -3 deg at the topend maybe a little less, you might/might not notice no knock/retarding.

So essence you really need a tuning device to make, safe reliably power.

My suggestions...

Invest in a greddy emanage or a standalone ecu, i would say even a vafc2 and synapse missing link (vafc2 would work but not the best). The synapse missing link is better than the CT box as it doesn't clamp the map voltage and thus allows the full range of adjustment for temp, altitude etc.

The missing link is a mechanical way to hide boost based on an internal valve which limits the pressure the map sensor see's (the vafc2 and missing link worked well on my car - i dont run any map clamp deice any more nor do i rely on it in boost). I would use the VAFC2 to only lean out the bottom of rev range but leave it unadjusted everywhere else in the revrange, possibly lower vtec as well which will be beneficial for power. Unfortunately the vafc2 cannot enrichen the mixture properly and when leaning out advances timing inadvertently (wont be a problem lower down when not making much boost, but would be higher up if leaning out). The VAFC2 will not be learnt over in WOT, because the fuel trims are not adjusted in WOT (even hondata changed their webpage when me and another guy pointed this out ).

With the above issues, a standalone ECU or greddy EMU will allow you to then lower the idling FPR psi to a more acceptable safe level, alter the timing, fuelling and vtec engagement properly leading to a better tuned and safer car. You can even fit bigger injectors and get a smaller FPR.

Good see you have a wideband for peice of mind, i use gatorback though the belts are hard to get hold of over here. Gates are good and are a little easier to get hold of, you will be able to cross reference some on the yank side for order numbers in the UK. TBH i think you will be able to get away with the belt being 2mm longer, as long as its the right ribbed design and its tight, thus doesn't slip.

Unfortunately getting hold of a pulley is nigh impossible in the UK, you will either have to source a 2nd hand one from the US marketplace on s2ki or buy one new and import it from (SOS - science of speed who will also sell you the correct belt), most AP1 owners fit these AP2 7psi pulleys.

BTW i am running 7psi, greddy emanage, 5zigen singlepipe exhaust, berks HFC, tracysport manifold, and a catchcan. I have installed the SC and tuned the car myself, it made 370BHP and ~240 lb/ft.

good luck.

Hope this is of some help.

mattxx

Quote:

Now am i correct in thinking you are just using the comptech box (ie map clamp box) and you are 'aftercooled'?

Yes, that is correct.

When you say "bolt ons" do you mean like intake, exhaust bolt ons? If so, then yes, I do have HKS hi-power exhaust w/ decat and the intake that comes with the CT kit if that counts.

I just want to thank you immensely, Irvatron. Thank you so much for all of this VALUABLE firsthand information! I feel much more knowledgeable and comfortable now.
The way you wrote this makes it so simple to follow and understand. I get it all and will use it too.

Since my first post I have reconsidered and will get either a Greddy EMU or AEM EMS 2. I am not in a rush anymore to get a pulley quickly and will just change the belt.
I'll do the upgrades the proper way. I hear that Greddy EMU works but is more difficult and complicated. Also that it is a good deal if the buyer knows what he is doing and is
willing to work with it. I do not know what I'm doing when it comes to tuning. So to make it simple with less visits to a professional tuner, I'm under the understanding that
it is best to pay more for the AEM EMS. Would you agree?

mikey k

I'm with Irvaton on too many aspects of that post
I managed to get a poor AFR with a stock install and Amus exhaust
Do it properly!
I always bought my pulleys and belts from the US
Get a AEM EMS 1052U with the the inbuilt wide band O2

s2konroids

Yes by bolt on's I mean an after-market exhaust, manifold etc. You 'might' get away with the CT box and your exhaust on 7psi but its likely you'll have to jack the fpr up to around 65-70psi at idle.

When i had my vafc2, missing link, tracysports manifold and decat it was on the brisk of not being able to get the AFR in line. I did manage to get it inline with the FPR hiked up-to around 70psi, but i wasn't too happy and knew it would be temporary in my mind even though the AFR was inline but i was always worried about knock.

This reminds me, initially whatever i did to the FPR it would not respond on the dyno ie not enrich the mixture, turned out i had some voltage drop at the walbro pump connection, thicker wires direct from the battery sorted it (pump can not deliver due to lack of juice). I take it you have an after-market fuel pump?.

When you get an ECU, you then remove the CT box/missing link in the ECU's setup, Mase etc including me will use a boost clamp function, this only allows the voltage to get to ~0.5psi which is ideal as the car see this amount normally aspirated.

I don't agree its worth it to pay more for an AEM on your setup, but that's me having tuned my car myself. However finding someone who will map the GEMU correctly could be difficult and thus possibly end up more expensive in the long run, Mase will have a generic map that he will tailor to your car probably a couple of hours tops also Mase is supposed to be good, thats not to say other people are as good if not better. If you want to spend the money, get an ECU, ditch the FPR and get bigger injectors - this will a cost a lot more but then theres potential for more power and safer. For me 7psi is enough and the car should take 7psi all day long, i just feel when you get to 10psi+ on a stock engine your pushing it.

The greddy EMU isn't that difficult (its a little difficult to work with), i took a punt on one for £350 with a greddy pressure sensor and managed to get it working superbly, there were problems with the internal dip switches being set incorrectly and harness so i modified it slightly to do proper vtec engagement control. The thing with retaining the stock ECU is your have all the functions and OBD error codes etc, its based on adjustments to the stock ECU but does it directly (via injectors etc) so its much better than another piggyback which tunes via the map sensor voltage.

It does everything i need and everything an AEM would do, however its not quite as good as an AEM when i looked at the software (but that's to be expected), you will also get a slightly smoother, quicker result with an AEM and you have a little more resolution to play with IMHO i think i would only gain a couple of bhp/torque with an AEM overall.

I have brought the AFR in line, lowered the FPR to around 59psi now, sorted the ignition timing which needed retarded even on 7psi, lowered vtec to 4k, upped the rev limit to 9100 (true limit 9000k) plus i can monitor injector duty cycles rates etc which are max 82% - so you can see from that its working fine but no room for any other modifications.

So an after-market tuning device is essential, of course prices for stuff will rocket.

I'm happy with my setup, i have wanted a little more power at times but i dont really want to spend more money/time on the car plus I'm turning my attention to mapping diesel cars now (my yaris d4d).

Cheers

mattxx

I understand 70 PSI of fuel pressure at idle if I go ahead and do this mechanically. I'm now debating if I should due to the sound of the possible complications. Can't be good for gas mileage.

Yes, I have the fuel pump that came with the CT SC kit.

It's impressive what you did with just 7 psi.

s2konroids

I ran it for a while and had no problems, the problem is people used to come into the shop and have an FPR jacked up too much. When jacked up too much you force too much pressure through an injector it actually fails to open/or blow its open and thus not deliver enough fuel - i didn't witness this.

I think if you went for 7psi and keep your exhaust and that's it, you may need to adjust to the 65-70psi range i cant say for sure.

Your LTFT/STFT trims will be out of sync too, yes it will be a little worse for mpg - again i more-or-less sorted this with the GEMU, the thing is in partial throttle you cant go outside the check sum (what the stock ecu is prepared to work with).