7m Na-t vs 7mgte ?

[JAYspec]

So i recently bought a 89 5spd n/a, running. The previous owner blew the HG and installed a HKS 1.2MHG with ARP head studs.
I currently have ALL the parts i need to NA-t my 7mge....

I'm wondering if it would be a smart move to go na-t, if so, would my risks be the same as going 7mgte?


Thanks, Jay

 

[shaeff]

Higher risk of detonation, simply due to the higher static compression ratio. However, if you take the time to do it properly you won't have any issues. You need to tune it, or have it tuned well.

Best way, in my opinion, is to run all GTE wiring and electronics. (including the ECU) If I ever find a decent GE block for sale, that same setup will be going into my truck.

 

[Jimbo]

is there a way to avoid detonation while keeping the NA pistons?

 

[RockPaperSwoRD]

n/a 7m runs on a karman vortex airmetering system, basically there is a flap that opens and closes to determine how much airflow is going into the engine meaning its hard to get a good tune on, hence the switch to 7mgte electronics which uses a standard maf signal.

to avoid detonation get a meth injection kit.

the hg you have should have already lowered the compression ratio abit, i think theres a chart somewhere on the forum that will tell you what your CR is with different thicknesses of HGs

 

[whitemike]

the hg you have should have already lowered the compression ratio abit, i think theres a chart somewhere on the forum that will tell you what your CR is with different thicknesses of HGs

That's solely dependent on the amount of metal taken off of the block/head, which should be measured before assuming anything like this.

 

[shaeff]

n/a 7m runs on a karman vortex airmetering system, basically there is a flap that opens and closes to determine how much airflow is going into the engine meaning its hard to get a good tune on, hence the switch to 7mgte electronics which uses a standard maf signal.

to avoid detonation get a meth injection kit.

the hg you have should have already lowered the compression ratio abit, i think theres a chart somewhere on the forum that will tell you what your CR is with different thicknesses of HGs

No it doesn't. The 7MGTE uses a Karman Vortex metering system. The N/A's use a vane type system which is less accurate, and it's NOT like a MAF/HFM (hot wire type sensor).

Swapping to GTE electronics opens more doors for easy tuning BECAUSE of the AFM (karman type), but if you want to get rid of that all together look into one of the MAFT systems.

RockPaperSworRD- you have lots of reading to do.


As for keeping detonation away, a good tune goes a LONG way. There are many ways to combat it, including higher octane fuel, and meth injection. The best thing though, is a good tune by someone who knows what they're doing.

 

[1986.5supra_kid]

while where talking about na-t. i am on the same road (1986.5 supra 130xxxmiles) i want to get a turbo form gte and bolt it on and run low boost. i have done some research but i want to keep my ge electronics. everyone says gte swap. but i have heard na have less boost lag due to higher compression ratio. so my thoughts where ( get 440cc injectors, boost controller and one for controlling fuel, larger fuel pump, better plugs, and all the hard pipes,turbo,manifold) bolt it together and have a dyno tech or someone in the racing business tune it (someone very educated) i would appeciate it if i have some links of previous successes with the na-t converson

 

[7Matt-GE]

mmm na/t talk im throwin GTE pistons in my block. so i can do more boost without having to worry about detonation.

 

[mecevans]

i broke down my NA-T into different points of concern. Im keeping the high compression so preventing detonation is my main concern.

Fuel- walbro,fuel filter, flow tested and clean injectors
Electronics- GTE recondition wiring harness. check for cracks broken wires and use coax for knock sensors. rebuilt cps, new plugs and wires, extra grounds
Cooling- ebay silicone rad hoses and will be buying on of the cheaper rads from here, gte fan
Seals- ebay gasket kit with toyota for the important ones, stock HG
Head-shim valves, bbc springs, arp studs
Oiling system- canton 90 filter adapter, wix 51155 filter, shimmed and lowered gte pump and maybe pan kickouts. dm na-t oil lines
Intercooler- will be stock form now, once i start turning boost up ill get one.
Exhaust- ebay 3in dp stock catback
Turbo-stock ct26 with ported wastegate dm cone filter

keeping the Engine and air well cooled is probably the best thing you can do besides tuning.

 

[aznboik1mva]

running meth would also prevent detonation..if done correctly and u had the money

 

[themadhatter]

The best way of going a na-t imo would be
-7mgte manifold and turbo
-intercooler and charge pipes
-bov
-stock 440's
and tune it all with megasquirt I am currently running one on my turbo mr2 and i'll be honist its not the easiest thing to learn but well worth the effert and a great bang for the buck

 

[ValgeKotkas]

Find a donor with 7mgte.

 

[MK3er]

Less head ache with the gte swap and alot safer ge block doesn't have the oil squirters that the gte block nor do they have oil return of feed locations. And if you do go ge-t and do decide to swap electronics have fun theres a few slight changes that cause a big head ache. I will personally be going gte swap because im looking for bigger numbers and a blow engine will ruin your day fast!

 

[Nick M]

9.2:1 isn't exactly high compression. I would think it easier to just swap the whole engine, but I guess sometimes if the GE engine is ready to go, then I understand adding the blower. Here is one for you from back in the day.

http://www.supramania.com/images/hosted/nickm/Cartech 7MGE1.jpg

http://www.supramania.com/images/hosted/nickm/Cartech 7MGE2.jpg

And a did you know....HKS back in the day sold a piggyback computer, the PFC-FCon for their 12 psi T04B turbo kit for the 7MGE.

 

[7Matt-GE]

i don't see what the big fear is about detonation. just run low boost that'll help big time. plus in reality you really don't need to run much more than 7lbs on an NA piston because of the higher than turbo compression you'd be making some decen't power. shit my friends 240 has the KA-T motor in it and he boosted it with 10lbs and now makes close to 300whp on stock EVERYTHING!


my N/A-T build will consist of:
turbo OEM quality (NPR) pistons
stock turbo (possibly ported depending on how much money)
GTE electronics
GTE ecu
SAFC
Turbo cams
NDC bearings
stock rods

im also doing a full block refreshment at the machineshop (Never skimp out on that)


i wanna see what the GE block can do. i have a feeling you can actually make some good numbers on it without actually needing oil squirters.

somewhere on this forum (can't remember which thread) someone had mentioned that oil squirters on a GE block wouldn't really be needed unless you are makin 500+ whp but here's my question, how well does oil squirters KEEP the block cool? im not familliar with squirters at all.

 

[Nick M]

They cool the piston, not the block. Unless you want to count minimal splash.

 

[7Matt-GE]

is that supposed to keep it out of detonation and if thats the cause wouldn't coating the head lower the temp to prevent the detonation? sorry for all the questions. there's gotta be a way around that.

 

[shaeff]

Less head ache with the gte swap and alot safer ge block doesn't have the oil squirters that the gte block nor do they have oil return of feed locations. And if you do go ge-t and do decide to swap electronics have fun theres a few slight changes that cause a big head ache. I will personally be going gte swap because im looking for bigger numbers and a blow engine will ruin your day fast!

Early GTE motors didn't have oil squirters either in Japan, but were always in the USDM GTE blocks. My '89 block (jdm tyte) block doesn't have them. Oil feed/return locations are easy enough to be a non-issue. There are no "big headache" wiring changes, so long as you run electronics that match the year of your car. I'm not entirely sure what you're getting at, unless you tried using the wrong year wiring/electronics.

i don't see what the big fear is about detonation. just run low boost that'll help big time. plus in reality you really don't need to run much more than 7lbs on an NA piston because of the higher than turbo compression you'd be making some decen't power. shit my friends 240 has the KA-T motor in it and he boosted it with 10lbs and now makes close to 300whp on stock EVERYTHING!

With a 7mge and 10psi, you should be making close to 300rwhp, in my opinion.

my N/A-T build will consist of:
turbo OEM quality (NPR) pistons
stock turbo (possibly ported depending on how much money)
GTE electronics
GTE ecu
SAFC
Turbo cams
NDC bearings
stock rods

im also doing a full block refreshment at the machineshop (Never skimp out on that)


i wanna see what the GE block can do. i have a feeling you can actually make some good numbers on it without actually needing oil squirters.

somewhere on this forum (can't remember which thread) someone had mentioned that oil squirters on a GE block wouldn't really be needed unless you are makin 500+ whp but here's my question, how well does oil squirters KEEP the block cool? im not familliar with squirters at all.

If you're putting turbo pistons in your GE block, then you essentially have a 7MGTE. The blocks are identical (save for structure changes later on). You're not pushing any limits of the GE block, you're simply turning a GE into a GTE, which isn't N/A->T. N/A->T implies that you're on a GE block with stock compression.

The GE block can do exactly what the GTE block can do, because it's the same casting. Oil squirters aren't a necessity by any means, but they do help.

 

[7Matt-GE]

thank you shaeff!

 

[shaeff]

Welcome. Sky is the limit, dude. Build it well, and to exacting tolerances. Tune it very well, leaving a margin for error (bad gas, etc...) and you'll have no problem making serious power.