EA82T (L) Bypassing TB hot water ?

[discopotato03]

Hi all , I was thinking of doing this and would like to know if it makes any difference .

 

Also are the std hoses 7mm ID and do most just run one longer one around the front of the throttlebody .

 

Cheers and thanks , Adrian in Aust .

[ausubaru92]

Are you talking about the water passage that goes though the MPFI throttle body, if so, leave it as is. It is there to make the fast idle, pcv and purge features work propperly

 

There is not enough water flow to make a preformance difference, it only warms one part of the throttle body, remember its only a 7mm hose.

[discopotato03]

I'm not really sure how its possible to come to that conclusion .

 

The Fast Idle (I assume you mean that FICD valve) is an idle up for when the air con is running and my A/C's gone over the shoulder . The PCV valve is not connected to the throttle body and the purge function is controlled by a separate solenoid valve .

 

From looking at the Factory manuals and one in the flesh all I can think is that the water heating is there to prevent icing in cool humid climates .

I find that with the coolant log close to the garden variety (non Spider) inlet manifold everything's pretty much at coolant temperature anyway .

I have one of those digital thermometers (Protek through Jaycar) and it reads virtually same temps in the inlet manifold everywhere .

 

The Spider is very different with the top section bolting to the coolant log and short injector adapter stubs . From what I've seen the turbo spiders run coolant to the TB but I don't think the NA ones did .

 

Anyway for a short reasonably cheap section of 7mm bore EFI hose its easy to try and revert if it creates problems .

 

Cheers A .

[SmashedGlass]

i did the same when i swapped a KA24DE throttle body from a 240SX onto the CA20E engine currently squatting in my '87 Nissan 200SX. i simply ran the inlet and outlet hoses together, bypassing the TB altogether (had no choice; though i live where it gets cold and wintery, the damn outlet elbow on the KA TB faced to the rear and couldn't be turned....). has caused no problems through a year and half.

[subyrally]

ive byppassed the coolant lines around hte throttle body in both my cars that were fuel injected. driven my impreza like that in negative temps and lots of snow, noever had any issues with that. never had any issues with my rx either, but it rarely saw temps below 10*f, so im not sure how it would have dealt with sub zero temps, but im sure it would have been just fine. it never had any problems playing in the snow here though.

[Gloyale]

The Spider is very different with the top section bolting to the coolant log and short injector adapter stubs . From what I've seen the turbo spiders run coolant to the TB but I don't think the NA ones did .

 

 

Non spider EA82, MPFI also had warmed TB. 2 hoses, one in, one out. hose come out of and go back into the coolant passage section of the intake.

 

On spiders though, the tube comes out of the intake, but the return is to the heater core to water pump tube. That tube runs under the intake, from heater core back to Waterpump.

 

My question is, do you have the coolant return tube from the Spider intake engine? If not, then where are you going to bypass the hose to? Non spider engines don't have the extra nipple on that tube. I think you could just cap off the outlet line on the coolant crossover.

[discopotato03]

Yes I've got that covered . My 2nd Arachnid manifold came from a rally person who bought a Vortex engine but couldn't use the inlet because RX's were never homologated with them , has that heater pipe as well .

After that I found out about a rare for Australia late 87 Vortex AWD turbo and bought that engine and box plus all the engine control electrics - so it should have that pipe as well . Thing is I reckon the N/A one would have been the pipe to have though the turbo ones no prob to bypass .

The thing I'll only have one of is the spiders unique EGR pipe though Im sure getting the rally persons unused one would not be too difficult . Just on that did someone here once say that the N/A Spider engines didn't use and EGR system ?

 

Cheers and thanks , Adrian .

[Gloyale]

The thing I'll only have one of is the spiders unique EGR pipe though Im sure getting the rally persons unused one would not be too difficult . Just on that did someone here once say that the N/A Spider engines didn't use and EGR system

 

I don't think it's a Turbo/NA difference. It's about the Year. My Spider is from a 90 or 91, and it does not have an EGR valve. Of course it is not from a turbo either.

[calebz]

I don't think it's a Turbo/NA difference. It's about the Year. My Spider is from a 90 or 91, and it does not have an EGR valve. Of course it is not from a turbo either.

 

 

Actually, I think it is a turbo/NA difference.

 

I have 2 NA spiders. One is an 87.5 for sure, the other is of an unknown year. Neither have EGRs.

 

However, I have a friend with an 87.5 that does have the EGR

 

 

Just to make it more confusing, I had an 88 non spider turbo with no EGR:-p

[Gloyale]

Actually, I think it is a turbo/NA difference.

 

I have 2 NA spiders. One is an 87.5 for sure, the other is of an unknown year. Neither have EGRs.

 

However, I have a friend with an 87.5 that does have the EGR

 

 

Just to make it more confusing, I had an 88 non spider turbo with no EGR:-p

 

Well in the USA. The only year with a Turbo Spider intake IS 87.5. FSM for 87.5 XT Shows only turbo have EGR. So for that year, it is a turbo/NA difference

 

I don't have an 88 XT FSM. But the L-series FSM for 88 shows that the EA82T has EGR, EXCEPT for the Cali models. Of course 4 cyl. XTs in USA in 88 where all N/A. But The EA82T in the L series is the only other MPFI version to compare to for that year. Perhaps 49 state XTs had no EGR, and Cali models did. Like the other MPFI EA82 of that year. So for 88 it would have to be a Cali/49 state difference

 

 

By 89, EGR valves where eliminated from all MPFI engines. 89 XT, and L-series FSMs show that no MPFI cars had EGR. 89 and after, no MPFI ea82, turbo or NA, had EGR.

[discopotato03]

Very interesting , I've never seen a real late Spider Vortex of either kind here in Australia so don't know the EGR story here .

 

I know this has nothing to do with TB water bypassing but I really really need to know about Spider Turbo cam profiles . Mine have an 8 , no second ring , 1third ring and I'd really like to know what the valve timing numbers are .

Here in Aus our late L MPFI turbo cams are shown in the FSM as 14 56 56 14. Your "Cali" EPA regs would have been more stringent than ours in that era and I suspect Subaru speced "clean cams" with more overlap to give an internal EGR effect .

 

The 20 60 60 20 cams from your N/A Spider Vortex look interesting and I wonder if I could get away with running those with 9 CR pistons and a much better header/turbo/higher flow cat . My 87 WSM also shows turbo cams for countries that didn't use cat converters and the timing specs are 12 58 60 20 . Thats basically your N/A Vortex exhaust lobes with our late L turbo inlet lobes but advanced 2 degrees ie 12 58 instead of 14 56 . I like the idea of the extended exhaust duration compared to inlet with turbo engines and with a better flowing header/turbo/cat etc it should pull up the bottom end torque - probably everywhere I reckon . Its not insignificant that those N/A cams have 40 degrees overlap where the non cat turbo ones have 32 .

Also those non cat cams were run with the typical 7.7 static CR and I want to use the 9.0 ones , thermal barrier coated to hack the extra heat .

 

To me cam profiles and CR are tied together and if I cam optomise both around performance then this EA82T may get me basic early EJ20T performance without looking out of place or adding any extra kilos . Our early Impreza WRX's didn't exactly set the world on fire with about 147/153 Kw to I think 1260 Kg .

 

Thoughts ? Thanks Adrian .