I'm going FREAK OUT. ---MR2T Issues Options

[root]

Okay, so I've this mr2t, and it has this pretty big turbo on it. Spools somewhere around 4500rpm. I personally hate that fact. Its an sc61 56trim t3/t4

So heres the thing. I was talking to the mechanic who did most of the work on it before I owned, and he thought I was off my rocker for mentioning that I could find a gt28 or a td06-20g for pretty cheap wholesale. The cars runs pretty rich right now and it doesnt have much of an exhaust. It was open down pipe, but I had to put on some old n/a duce piping some I could just drive it and not attract cop attention. So he's like "well that tiny arse piping is causing ur problems", but I tell him, "it was ODP last week. It still ran like ****". It was converted from afm to map the cheap way with a HKS VPC, GCC. Kinda old school, and it was never dialed in. He's tellin me that the HKS is better than AFM, and that I'd be crazy to pull it off and convert back to AFM. Uuuggghh. I thought the afm would adjust better to air differences than the HKS. Its not like the TOYOTA AFM was engineered for the engine or anything .

So my question to all ye here is: Am I really crazy for wanting a gt28 ball-bearing turbo? Would this sc61 really spool that much faster if it was tuned? Yes, I know tuning can help, and I am not saying that its not important. But how much could it REALLY help with this huge freaking turbo? Its not gonna spool near what a BB turbo would, and a gt28 should put all the boost I would ever want, even when its forged and built, right? He's like "well that turbo will give you pressure when you need it later". I've seen folks with ct20b's do 17+ psi easy. Why do I need a turbo that was made a a single turbo supra? My friend's 2jz has a smaller single turbo than mine, and that car is insanely fast.


Sorry for the rant. I'm just a little on edge with that guy right now. You people have always been helpful to me and my Toyota cars. I just need some real advice and a place to vent.

Thanks

[lagos]

depending on how the vpc is setup, it could be hurting your spool.
your mechanic is right, a map based system is better, but in your case, you are probably better off trying to go back to an afm.
you should also make sure that the last owner wasnt trying to run 550cc injectors with that vpc. that could be whats causing your issues.

as far as turbos go, the one you have is way too big for what your trying to do. the gt28rs would be awesome on an mr2. it spools very quick and makes good power, but is limited to about 300hp.

bottom line... fix the vpc issues first. then decided what you want to do with the turbo.

[root]

As far as injectors, he didnt touch em as far as I know. I'm 99% sure they are stock, but the vpc could have the 550 chip in it. I've never tore it apart. If I gonna go with MAP, I'm gonna do it the right way with a standalone, or atleast somthing more up-to-date than the vpc. MAP-ECU2 looks kinda cool, but I'm still in the middle of researching it some more. Anyways, for now I'm gonna pick up the AFM.

I can only get 300ish from a gt28rs w/ supporting mods? Hmmm......I guess that is my power goal, but I know how these things work. You get alittle bit, and then you want alittle bit more. Power is like potato chips. Basicly, I'm looking for a turbo with awsome spool that will get me to my power goal, and I want it to have a little room for more, if I go all out and build the motor. I can foresee headwork and some forged pistons in my future.

Would a td06 20g be good for what I want, or would I be sacrificing too much spool. I've never heard bad things about it, but then again, I havnt really looked to far into it either.

[x_itchy_b_x]

get it mechanically sound first. then go standalone, and have it tuned right.
then theres no reason why it shouldn't run great. i'd keep the turbo you have on there and tune the engine for that turbo. playing with the cams/timing can make a turbo spool alot quicker. also increasing VE will help that turbo spool quicker, like an intake manifold or aftermarket cams.

[Akimbo]

i hate you!

[root]

get it mechanically sound first. then go standalone, and have it tuned right.
then theres no reason why it shouldn't run great. i'd keep the turbo you have on there and tune the engine for that turbo. playing with the cams/timing can make a turbo spool alot quicker. also increasing VE will help that turbo spool quicker, like an intake manifold or aftermarket cams.

The reason it runs like crap is because of the fact that the crack-smoker who owned it last converted it to map, but never tuned the thing. And, to make matters worse, there is no o2 sensor on it at all. So the ecu has no clue what the mixture looks like, so it riches the heck out of it. So, yeah, I do need to get it running good. An actual o2 sensor would be a start. AFM would next. Unfortunately, the decision to pull the turbo has already been made. Somebody on mr2oc threw enough cash to convince me that it was a good idea. My manifold has a crack anyways. Small, but its there. For now, until I get enough money to properly get this car into the numbers the right way, a ct26 is lookin like the way to go. Just for now. I really need a quick fix so I can drive it to school and work.

Dont get me wrong. I'm sure that turbo would be sweet on a properly setup motor, but is it not way too much for my car? I just dont think a turbo should be this much further ahead of the rest of the setup.

But, then again, smarter than me have worked on these engines.

I hate you!

........lol. When I get it running right, I let you drive it sometime Ryan.

This post has been edited by root: Aug 18, 2007 - 6:26 PM

[jgreening]

Here is my advice:

You need to decide what turbo you are going to go with first. Go do some searching on MR2OC for some argumentative threads about "lag" to get a feel for the trade-offs.

The larger one will have more lag but could be VERY fun if you get it running right.

After you select your turbo, ditch the VPC. Do not use a ROM tune. Do not use a AFC.

If you keep the bigger turbo, get a standalone. Period.

If you go with the GT28RS, you can use the stock ECU and AFM even on stock 440's. If you get a standalone with the 440's, you will have better performance and probably get another 20-30 whp (assuming a proper tune). If you get bigger injectors, get a standalone. Period.

This post has been edited by jgreening: Aug 18, 2007 - 8:30 PM

[lagos]

if you driving around with no o2 sensor, then your spool is going to be terrible, regardless of what turbo is on there. fix the o2 sensor 1st, before you decided to do anything else. trust me on this.

[root]

if you driving around with no o2 sensor, then your spool is going to be terrible, regardless of what turbo is on there. fix the o2 sensor 1st, before you decided to do anything else. trust me on this.

Indeed, the o2 sensor is my first thing.


Just our of curiosity, with a good tune, where would a turbo like this (the sc61)spool at? 4k even 3k?

This post has been edited by root: Aug 19, 2007 - 5:35 PM