What are the differences in the two. I know the MAF sensor changed and I read somewhere that pre 87' had gen 1 heads. What are other differences?

87.5 xt turbo's got the spider intake and like 30 more hp, a little off topic but it's what i know for certian

87.5 xt turbo's got the spider intake and like 30 more hp, a little off topic but it's what i know for certian

 

Don't think they got any extra power. Definitely not 30.. Maybe 3-4 because of better flow, but otherwise everything is the same as the non spider motors (injectors, fuel pump, boost levels and such)

no real power differences (maybe like 1-2 hp), MAF is different, disty, and a few bolt on stuff. Yes, pre '87 had gen 1 heads for sure, most of them up to '88 did when they started using gen 2 heads and gen 3 heads, are mainly current NOS and replacements for cars under warranty back in the day (like '90). Cams were also different I believe and there's something else I think is different but I cannot remember. Blocks are all the same, heads are the same, cam cases and covers are the same, intakes I believe are the same and so is the exhaust and the turbo as well.

I knew the MAF sensors were different, but what makes them different? I'm assuming that most parts are interchangable between to two?

I knew the MAF sensors were different, but what makes them different? I'm assuming that most parts are interchangable between to two?

 

The MAF's are completely different (as in different theory of operation - one uses a hot wire, and the other a flapper door), as are the distributors, so the ECU, and the parts of the wireing harness used for those components are too. Most other parts probably would interchange fine.

 

GD

PRE 87 injection was gang fire, where as post 87 injection with the optical distributor is sequential injection. Better for fuel economy and emissions fo sho...

 

(pretty sure, but I'll have to recheck my wiring diagrams to make sure)

 

-Mike

PRE 87 injection was gang fire, where as post 87 injection with the optical distributor is sequential injection.

Nope. Sequential injection is impossible without a cam position sensor. No MPFI EAs have sequential injection. Its all batch fired.

I got curious about this, so I went and compared the 86 FSM to the 88 FSM.

 

The differences I noticed:

MAF - Old system is flapper, new is hot-wire

Distributor - Old system is hall effect w/ vac advance, new is optical, timing controlled by ECU

Knock Sensor - Old system has two wire, new has one

TPS - Old system TPS just has an Idle switch, and fully open switch. New has an extra potentiometer to determine throttle position

WGDS - Old system the wastegate is a direct hookup. New has a solenoid that slightly controls boost. I think its an altitude compensation thing.

Pressure Switch - Old system has one and uses it as a fuel cutoff. New one doesn't, and uses the MAF signal to determine fuel cutoff.

 

Everything else seemed to look like it worked the same. SO, theoretically one could swap those parts on to their 85-86 and the ECU, and you could gain a small amount.

I got curious about this, so I went and compared the 86 FSM to the 88 FSM.

 

The differences I noticed:

MAF - Old system is flapper, new is hot-wire

Distributor - Old system is hall effect w/ vac advance, new is optical, timing controlled by ECU

Knock Sensor - Old system has two wire, new has one

TPS - Old system TPS just has an Idle switch, and fully open switch. New has an extra potentiometer to determine throttle position

WGDS - Old system the wastegate is a direct hookup. New has a solenoid that slightly controls boost. I think its an altitude compensation thing.

Pressure Switch - Old system has one and uses it as a fuel cutoff. New one doesn't, and uses the MAF signal to determine fuel cutoff.

 

Everything else seemed to look like it worked the same. SO, theoretically one could swap those parts on to their 85-86 and the ECU, and you could gain a small amount.

 

Thats what I was looking at. The biggest thing would be cuting the connecters for the ECU off the newer wire harness and putting them on the older wire harness because they don't plug into the same places.

Might be easier to just swap engine wiring harnesses...

I actually thought about doing this to the EA81T with how rare they are and difficult to find parts. The EA81T intake has almost nearly an identical sensor system as the pre-87 EA82T.

Cams were also different I believe

 

by different do you mean better, or just different due to different dimensions and/or tolerances in the head and cam tower?

Actually, the cams are different. I had posted somewhere before the different duration.

 

The later cams are probably actually better. The early cams are the same as the carb cams. Though I think the difference is minimal.

you said the pre87 models had a direct waste gate control and 87+ had a boost solinoid? well, I have a '88 XT with spider and hotwire, but without a boost solinoid? how can this be? perhaps because it a euro? (yet another difference to add to the list)

you said the pre87 models had a direct waste gate control and 87+ had a boost solinoid? well, I have a '88 XT with spider and hotwire, but without a boost solinoid? how can this be? perhaps because it a euro? (yet another difference to add to the list)

 

Correct.. the euro model EA82 runs on a different set of rules than USDM.

 

IIRC, the EDM models came out at 136hp

...and a factory oil cooler (P/Ns 21315AA001, 21319AA001, 21317AA001, 806959010, 806923020, 45711GA021[sedan/wagon/3d], 45711GA030[XT], hmm this list is longer than I thought.. lol I should just scan the part page)....and a different crank shaft P/N 12201AA030

Can you tell any difference in power between the two? (pre 87' and after 87') Does one take power mods better then the other?