Gen 3 Vs Gen 4, 3S-GTE Options

[fran]

Hello!!! i read about the diferences, upgrades ++ about 2gen vs 3gen 3S-GTE`s but i didnt read anything about the 4Gen 3S-GTE. Anyones knows the diferences betwen those engines? what parts are the same, what performance parts cant be use on the 4gen?

[pitcelica]

The alternator on the 4th gen is larger with a higher amp output (not sure of the number right now). I'm running individual coils on my gen3 I bought a gen4 alternator (yes it bolts right on), so at higher RPM i expect there to be more of an amp draw than the distributor with 1 coil. I'm not sure if this is the reason that toyota put the larger alt in though.

Why COP should require more amps than distributor? It shouldn't. Each setup requires the same number of coil charge/discharge for a given RPM. The only difference is that the coil charge duty is splitted to 4 different coils. This mean that each coil has more time to cool down between each charge/discharge event and this lead to less wear/coil change. The total energy drawn (power/amps) is the same between distributor and COP.

I'm not sure the gen4 alt is bigger because of the COP, who know, maybe the Caldina has more body electrical features than a Celica.

Sam

This post has been edited by pitcelica: Dec 15, 2013 - 10:27 AM

[match220]

The alternator on the 4th gen is larger with a higher amp output (not sure of the number right now). I'm running individual coils on my gen3 I bought a gen4 alternator (yes it bolts right on), so at higher RPM i expect there to be more of an amp draw than the distributor with 1 coil. I'm not sure if this is the reason that toyota put the larger alt in though.

Why COP should require more amps than distributor? It shouldn't. Each setup requires the same number of coil charge/discharge for a given RPM. The only difference is that the coil charge duty is splitted to 4 different coils. This mean that each coil has more time to cool down between each charge/discharge event and this lead to less wear/coil change. The total energy drawn (power/amps) is the same between distributor and COP.

I'm not sure the gen4 alt is bigger because of the COP, who know, maybe the Caldina has more body electrical features than a Celica.

Sam

What you are saying sounds like it would be true logically, but only for CDI style coils. TCI coils are different (what is in most Toyotas that I know of). There are two main ignition coil types that are in use in production vehicles, CDI and TCI or Capacitive and Transistor style. CDI coils build up a charge and fire only when they receive a high-voltage signal and have no charge unless it is given a signal. TCI coils (what Toyota uses) build up a charge when they aren't in use, and the coil fires when it receives the signal. Comparing a CDI to a TCI coil on a distributed system doesn't change much. But in a TCI 4-coil system, 3 of the coils have a charge built up when 1 is firing. This is why I installed individual TCI coils in my car and you definitely notice a difference at higher RPMs since the coils have more time to build up a hot spark. Individual CDI coils with a CDI controller will draw about the same amount of amperage as a single coil on a distributed system, so what you say would be true in CDI systems.

With that said, I have not been able to find out online whether or not the 4th gen coils are TCI or CDI. If you want I can ask another tuner friend and whenever he gets back to me I can post an update in here. I never looked into it since I used Audi coils. You can sometimes tell by the pinout on the coils, if they only have 2 pins then I would guess they are CDI, and TCI coils will have 3 pins (unless it uses the coil body as the ground, like our stock 3sgte did, then expect one less pin). But this isn't an accurate way to tell, just what I have noticed on cars/motorcycles that have CDI vs TCI setups. There are other features built into coils like ion sensing and built in individual igniters (some VW/Audi TCI coils) that would change the number of pins, making the pin-count method unreliable.

Considering Toyota uses TCI style coils with their distributed systems and also considering the size of the alternator, I would guess that the individual coils on the newer engines are also TCI. Because of this, I believe the 4th gen is TCI, but that is just a guess. I don't see any electrical systems in the 4th gen that would require such a large alternator, unless it is running TCI coils. The larger alt will keep the 4 coils from draining the battery when driving long distances.

This post has been edited by match220: Jan 7, 2014 - 7:44 AM