I've seen those arguments, but haven't paid them too much attention, because the piggyback approach doesn't appeal to me. If I do end up having to tune electronically I'd rather just spend a little more and get a good standalone ECU (probably AEM).

After thinking about my other question, regarding the need to reprogram after every change in boost level, I've realized that there is an aspect to all this that I don't understand at all.

All three of the kits I'm considering, Vortech, Comptech, and Lovefab, produce around 7PSI boost, but only the Lovefab requires a standalone ECU. The torque curves I've seen seem to indicate that the Lovefab produces much more boost at lower revs, but peak boost is about the same. Anyway, why does the Lovefab require a custom programmed ECU while the others don't?

Obviously, the simple answer is that there are limits to what the ECU can accommodate, but I'm looking for a more specific answer. Which of the limits of the stock ECU does the Lovefab exceed, and why?

 

well, you would put gears in because you need to get through them faster when dragging. The objective is to get through the lower gears as fast as possible so you can get to the hot spot in your powerband asap... this is why it would be ideal for 1/4 mile, or any overly technical track with little to no straight aways. This is another reason most racers (pro of course) carry around many different pumpkins, so they can use whichever gearing would be the most efficient based on the track. Day to day driving it wouldn't be nessicary, but my roommate has a SCed S with the 4.57s, and after driving it, I was amazed how quick redline came on... though whenever we ran (when our cars weren't nice paperweights as they are now... ) he would leave me at first, but I would start to catch up with him after 3rd gear...

 

reason being is that the comptech and vortech units come with a little computer you wire into the harness of the ecu. There are also more parameters that would need to be inline when running the Lovefab kit. You are running 750 injectors, which would need to be managed by something other than the ECU... It's not as plug and play, but there is alot more potential for more HP in the future with it than with a SC. It all depends if you would want that kind of flexibility, or if you'd be happy with a max of 12-13 psi (I know alot of SC guys are running 14, but I personally wouldn't want to operate at the max tolerance of anything, and that is the ceiling for the Novi1000... I think with Vortech you can run 15? Correct me please if I am wrong...) Also, there is the benefit of changing the powerband with different exhaust housings and trims, but again, that can be somewhat overwhelming as well. SCers are simple, boost comes on and rolls linear. TCers are a little more punchy in terms of when they spool... this is also why you see the drift S2ks running turbos and not sc... Either way, whatever you think you could sleep with at night and not be neurotic about...

 

gears & Nitrous. 4.57's w/ 75shot, If done properly you are looking at 1500 in Nitrous parts, 1399 in gears and enough money left over to take your woman on vacation.

If done properly and driven correctly, you should be good to go and capable of running with high 12 second cars on the freeway. Since you are not worried about launching, you should have no issues.

The beauty of Nitrous is it is not constant. I use it three or four times a month when I'm running with someone I know is faster.

 

Not quite. The Comptech uses a "ESM" which is the same as a MAP clamp. It blocks a MAP sensor input above a specific voltage level. This "hides" boost from the stock PCM. The Map clamp is not a computer.

Vortech uses a MAP clamp, and a seperate Timing controller. The Controller is supplied to Vortech by Split Second. www.splitsec.com

None of these units supply the extra fuel needed in boost. That is accomplished by the FMU's of each kit. A FMU is a rising rate fuel pressure regulator. It increases fuel pressure drastically to the injectors. The Stock PCM still "thinks" the car is NA.

The Comptech FMU has as static pressure adjustment. I don't know of any rate calibration "kit" available for the Comptech.

Vortech's FMU is a Fixed rate not adjustable unit. The Rate is 10:1 for every 1psi of boost, the FMU increases fuel pressure 10psi, over static.

Any FMU installed will increase static pressure over stock, due to the increased restriction in the return line.

 

The are several reasons behind it.

The stock PCM was never designed to see 7 psi from 3k rpm all the way to 9k. The fuel tables for a NA engine are totally different from what a turbo car needs. Lovefab is using 650cc injectors I believe. That's almost 2x larger than stock. An emanage can't compensate for over 550cc

A centifugal SC has a pretty linear boost curve. The faster the SC is spining, the more boost it's making. This allows you to get away with using a FMU for additional fuel. A turbo making 7 psi at 3K will have a delay from when boost is instantly applied to a FMU. This causes a delay additional fueling, the engine will spike lean, then go rich whe the FMU catches up.

The EMS offers full control over all engine parameters, something no piggyback controller can do.