Turbo Conversion

[Roger UK]

Just been reading the FAQ notes about swapping a 7M-GE with a 7M-GTE

However . . has anyone just bolted the turbo bits on a 7M-GE?

I know the main difference is the higher compression on the N/A engine - would this cause premature failure?

Is there really any need to change the Ignition system? Surely you could just keep the distributor setup . . .

The cheapest way would be buy a scrap car with a BHG or Big Ends gone and swap the pipes etc over (you can buy them in the UK for as little as ?200)

If it IS feasible, what kind of power would you expect without increasing the boost? (presumably more than a standard turbo, due to the higher compression and better profile cams)

[suprra_girl]

this has been done and is known as the NA-T

i believe that if they are intending on higher boost they usually rip the head off and put either thicker hg or deep dish pistons to take up the compression

but then again i ran 9psi and 280whp safely on 9.4:1 so i guess an na engine should take it ok
just run that high octane hehe

[jfunez]

I just bought a 87 turbo for $500 . with presummably bad main bearings...
I will be picking the supra this weekend....anyways...this is the exact same question that I have been asking my self...


since u can easily find N/A engines,why not use a A/N long block....
I still have to check it and do my homework as to which will be the most economical way.... who knows, maybe I'll do the bottom end...

any comments ,let me know..

[zby67]

hmmm... couldnt you just bore over by .20 or .40 to take up the compreshion with a thicker HG? and what is the down side of putting a turbo on a GE?

[Grandavi]

I think you can build a 7mGE to take a turbo without much effort if your actually rebuilding the motor.. but if you arent .. its still more economical to just replace it. Although.. having said that.. I have no idea what kind of ECU/harness/alternator, etc.. issues that would spring up..

[zby67]

Originally Posted by Grandavi

I think you can build a 7mGE to take a turbo without much effort if your actually rebuilding the motor.. but if you arent .. its still more economical to just replace it. Although.. having said that.. I have no idea what kind of ECU/harness/alternator, etc.. issues that would spring up..

well i have 2 7m-GE and plan on rebuilding one or both along with the trans. but from what im getting everyone on here hates the GE's and said even with boring over .20 with .20 valves, 3" exhause cold air intake and 550cc injectors i would be lucking to see mid 230hp witch if thats truly the case ill just do a stock rebuild. my goal is to get up to 300hp but hay the r154 is hard as hell to find and every supra i find only has the GE unless i go out of state.

[Grandavi]

The R154 is pretty easy to find.. in fact I think BIC is clearing out one for 300.00 (if its still for sale during thier move sale).

Lost of JDM ones floating around out there.. and they are fairly rocksolid.

I dont know about the US, but I can pick up a R154 for about 300.00 (delivered) in my city and a 7MGTE (with everything except the electronics) for about 749.00 (delivered) here. They are JDM.. but come with a leakdown test and compression test as well as a 90 day guarantee. For me.. its cheaper to buy the engine and drop it in than it is for me to replace the headgasket.

Other than the gamble on how good the JDM 7M is going to be... its a good deal really.

I am not THAT good of a mechanic to say if a 7MGE can be converted to turbo easily or not.. because I would assume there is more involved than simply bolting on the turbo or dealing with the compression issue. I just dont recall seeing any that were done successfully.. so I cant really be much of a help here.

[zby67]

Originally Posted by Grandavi

The R154 is pretty easy to find.. in fact I think BIC is clearing out one for 300.00 (if its still for sale during thier move sale).

Lost of JDM ones floating around out there.. and they are fairly rocksolid.

I dont know about the US, but I can pick up a R154 for about 300.00 (delivered) in my city and a 7MGTE (with everything except the electronics) for about 749.00 (delivered) here. They are JDM.. but come with a leakdown test and compression test as well as a 90 day guarantee. For me.. its cheaper to buy the engine and drop it in than it is for me to replace the headgasket.

Other than the gamble on how good the JDM 7M is going to be... its a good deal really.

I am not THAT good of a mechanic to say if a 7MGE can be converted to turbo easily or not.. because I would assume there is more involved than simply bolting on the turbo or dealing with the compression issue. I just dont recall seeing any that were done successfully.. so I cant really be much of a help here.

yeah you need a oilcooler run oil line and so on. i just want to know why everyone here is saying its inposible to hit 300 hp with the GE i thought higher compression helped increase hp... i dunno. im not looking to make this car a racing car im after a bad ass sports car witch it is now but more so and alittle faster. and ass for going balls out on the car it wont happen till i get a 1990 supra its the year i want.

[Grandavi]

I dont think it has anything to do with the compression really..

The engine is only capable of doing so much by itself.. if you understand how a turbo works (I will use the way I 'splained it to my kids) the turbo is like taking your girlfriend and giving her a straw... then putting a milkshake in front of her. Time how long it takes her to suck up one strawful of milkshake (no.. not sexual thoughts here..)

Then.. fill the straw with milkshake and blow it into her mouth as hard as you can. Thats.. boost.

A NA engine is sucking air.. while a turbo has the benefit of a pump pushing the air. Makes one helluva difference. You aren't going to defy physics by wishing it was different.

Remember.. I am not a mechanic.. but a NA (naturally aspirated engine) is forced to suck its air/fuel mixture. A turbo is beautiful because the exhaust will spin a tubine which pushes it in. Superchargers use the crank (unless they changed it) so they actually cost HP to run.. (if I remember correctly a 350 HP supercharger can use 50HP just to push the air)

Its probably far more complex.. but the engine does have its limitations.. and 300 HP is far past that if I understand its engineering. It just simply cant be done "normally" without possibly pumping 1000's and 1000's of dollars into it. So... its better that you take the NA and sell it for whatever you can get for it and put a 7MGTE into it (or a 1JZ) Your farther ahead and will save yourself a massive amount of headache..


of course.. this is an opinion from a guy sitting behind a computer.. not over top of an engine bay.

[zby67]

Originally Posted by Grandavi

I dont think it has anything to do with the compression really..

The engine is only capable of doing so much by itself.. if you understand how a turbo works (I will use the way I 'splained it to my kids) the turbo is like taking your girlfriend and giving her a straw... then putting a milkshake in front of her. Time how long it takes her to suck up one strawful of milkshake (no.. not sexual thoughts here..)

Then.. fill the straw with milkshake and blow it into her mouth as hard as you can. Thats.. boost.

A NA engine is sucking air.. while a turbo has the benefit of a pump pushing the air. Makes one helluva difference. You aren't going to defy physics by wishing it was different.

Remember.. I am not a mechanic.. but a NA (naturally aspirated engine) is forced to suck its air/fuel mixture. A turbo is beautiful because the exhaust will spin a tubine which pushes it in. Superchargers use the crank (unless they changed it) so they actually cost HP to run.. (if I remember correctly a 350 HP supercharger can use 50HP just to push the air)

Its probably far more complex.. but the engine does have its limitations.. and 300 HP is far past that if I understand its engineering. It just simply cant be done "normally" without possibly pumping 1000's and 1000's of dollars into it. So... its better that you take the NA and sell it for whatever you can get for it and put a 7MGTE into it (or a 1JZ) Your farther ahead and will save yourself a massive amount of headache..


of course.. this is an opinion from a guy sitting behind a computer.. not over top of an engine bay.

i understand how a turbo works. i just dont see why you wont see more hp with boring over and a 3" exhaust it still lets out more air. but i see your point just cause your sucking in a shit tone of air dosnt mean anything unless you can get ride of i quickly. so just do a stock rebuild new exhaust and cold air intake then start saving up for a GTE swap? and how much would boring over the GE actually help or will it hinder>? then once i get the GTE take everything i added to the GE and put it on the GTE cause im getting most of this from suprastore and there kits ment mostly for the GTE's anyway