[Jumpsteady]

i've been reading up on links i found in this forum about upgrading to 5mgte and understand the basics of what need to be done. im wondering what kind of power the bottom end of the 5mge can handle. i know having forged pistons would help me run higher boost but would the bottom end keep up? whats the highest boost anyone has got with the
CT-26 without problems with or without forged pistons?

also i'd like an idea about what it has cost other people on the turbo upgrade alone? i would be doing all work including pipe welding and fabricating.

thanks for any advice.

 

[WadeT]

You won't need any internal work for a CT26. Just make sure you get plenty of fuel to the cylinders and of course use a intercooler.

 

[pdupler]

Sounds like you're weighing the risks and cost vs. benefits. The stock headgasket is the weakest link, followed by the pistons. Both however would be reliable to 10 psi provided the fuel mixture and ignition timing were always absolutely correct. Therein lies the rub. Face it, if you are proposing nothing more than jury-rigging an otherwise stock fuel and ignition system as has been popular, then you have to accept that there is going to be some risk involved as these contraptions become much more difficult to tune than a stock motor and the consequences of being off by just a little bit are grave. When tuning, most err on the side of richness and retard, but of course you sacrifice power. Its all a matter of how much risk you are comfortable with. I'd budget some dyno time with gas analyzer if you want to maximize the boost. The bottom end I've always heard is good to 400hp so you probably don't have to worry too much there unless you suspect previous overheating or oil starvation. As far as cost, I believe that to do a decent job, and figuring typical salvage yard prices, its going to cost you in the range of $1500 to $1800US in parts and fabrication. Others have scrounged some real steals on used turbos and done it for much less, but most of us don't have that kind of luck. Remember too that with used parts, there is risk. A great many have had to rebuild what they at first thought was a good turbo after only a few hundred miles. I'd say if its your only car and you don't have at least twice as much $ in the bank just in case something goes wrong, you probably ought to postpone the project. Of course if the sup is a second car just for hobby, then you should go for it ASAP. Keep us posted on what you decide.

Phil D.

 

[Jumpsteady]

thanks for your input.

i am going to go ahead and put a CT26 on my 5mge. i am buying a manifold off a 7mgte off EBay right now.

Currently there are two CT26 turbos on Ebay both are a little over $100 dollars at the moment but i dont know enough about turbos themselves to place any bids right now. Any suggestions on them? item numbers 2409668155 and 2409656025.

also there is a farely large intercooler (2409613694) but the openings are on opposite ends which im sure will make routing the plumbing a bit more difficult. Does anyone know if it will fit? 28" x 14.5" x 2.25" end tank to end tank. its in houston too so i could go pick it up and save on shipping or would i be better off with a stock 7mgte intercooler?

do any of you recommend a fuel pump upgrade or will a rrfpr work just fine for the CT26?

how about the ignition system? what type of aftermarket components are any of you running?

i dont plan on "jerry rigging" anything. this car is drivin daily but i could get by with stealing my other car from my girl for a little while. i dont have hundreds of dollars to spend so im looking to buy a used turbo. when shopping for a used turbo, what should i look for? what is a good price for a CT26 in good shape?

i work in a CNC machine shop so i can make custom peices i might need. also i have a friend that owns a metal fab shop where i can fabricate my intercooler piping and oil return line.

hopefully i wont have 1500 to 1800 dollars wrapped up in this project like you mentioned. but i will do what needs to be done to prevent my engine from grenading on me.

what kind of rates am i looking at to have this tuned on a dyno with a gas analyzer?

thanks for all your help,
Nate

 

[pdupler]

Anytime you add a rrfpr and boost retard device, that to me is "A-team" engineering. After all, you're trying to "fool" the stock systems so you can make boost, right? Car manufacturers spend millions of dollars on engineering and testing engine systems. Compared to that, slapping on a turbo and a bunch of gizmos for under $1500 is jerry riggin. Not that theres anything particularly wrong with that, the A-team always got the bad guys in the end.

Good used turbos I've seen go for $300 - $400 while rebuildable ones go for $150 -$200. The stock fuel pump is good to about 75-80psi, above that the flow drops below what you need to support the hp you're making, i.e. its probably safe for 6-8psi of boost. Most people get a walbro or similar anyway because stock pump is usually already close to the end of its useful life. Jacobs and MSD make ignition that will retard under boost. If you try any other brands, let us know because both of these have their pitfalls. If you have the ability to do much of the fabrication yourself, then you can definately do this conversion cheaper than most. Good luck and keep us posted on your progress.

Phil

thanks for your input.

i dont plan on "jerry rigging" anything. this car is drivin daily
Nate

 

[Supra Bob]

Anytime you add a rrfpr and boost retard device, that to me is "A-team" engineering. After all, you're trying to "fool" the stock systems so you can make boost, right? Car manufacturers spend millions of dollars on engineering and testing engine systems. Compared to that, slapping on a turbo and a bunch of gizmos for under $1500 is jerry riggin. Not that theres anything particularly wrong with that, the A-team always got the bad guys in the end.

Phil...

The thing I think your not looking at tho, is that cars that come from the factory with a turbo are designed so that these things are not needed. Any retard under boost that is needed is put into the timing control reather than an auxilary unit and the added fuel requirements are handled via the fuel map rather than an S-AFC or RRFPR.

I really don't think calling a 5M or 6M with a turbo a"jerry rigged" contraption is accurate. While the Car makers may have spent millions on research and design, I would say a similar amount of developement has gone into those aftermarket add-on parts. RRFPR's (or FMU's as Cartech is now calling them) have been designed and refined over the last 25 years, with constant study and refinement still going on with them... MSD, I can almost garentee spent similar time and money on the same things...

I dunno.... just my $.02.

 

[pdupler]

Thats exactly what I'm looking at. Sure significant development went into each individual aftermarket component, but what we are trying to do is build a "system" Even toyota buys some components "off-the-rack" but we backyard mechanics can't even begin to match toyota for total system r&d. Thats not to say it can't work - I've done it. I'm just trying to drive home the point about reliability. Just as an example, I thought I had everything perfect after about a year of tinkering. I took off on a trip and my Airtex (also sold labeled as MSD, Holley, etc) hi-performance fuel pump cavitated as I got into the rocky mountains about 900 miles from home and eventually burned up. I had no way to predict the problem since I live at 600 feet elevation and it worked great here. Pump mfg exchanged it twice under warranty but ultimately I had to change to Bosche pump in order to get home. Trip was 4 days longer than planned. I was never quite sure if the three Airtex pumps in a row were faulty or if that particular model just didn't have enough suction head to overcome the supras tank conditions and pickup tube length at altitude. A toyota team of engineers would have been able to do some bench testing on the pumps, do some calculations and specify a different pump in the first place. I had find out the hard way. Thats why I call any kind of car modifications done by the owner "jury-rigging".

Phil

 

[Supra Bob]

Well, I agree with you on that aspect of it, but really, anytime you do anything to a car, even if its as simple as replacing a bulb with a non-OEM bulb, your taking that risk, possibly comprimising stock reliability, and I think every backyard "shadetree" mechanic realizes this from the get go. Of course, there are also cases where this tinkering can lead to a stronger more reliable system on the whole too as generally, we are not worried about overall profitability of a product (case in point.. the HG problem of the 7M's) I think thats even some of the draw for some people... how far they can "one-off" their car before it finally is too far or if they can improve overall quality....

Side note: I know the 7M HG issue was just a lack of long term durability testing on the part of Toyota and not a financial choice to use an inferior part...but it was just a readily available refernce that everyone would understand..