View Full Version : Please school me... turbo guys....

11-20-2008, 05:29 PM
My 90 xr7 is now a "spare car" since I got my Mark viii back, loaned it to my mom after she played deer tag. The cat is about to get a fresh coat of red.
In the meantime, while it sits idle, I want to toy with a t4 or hybrid thereof, to put on my xr. I will keep everything to go back stock at some point, since there arent too many sc xr's out there. I would like to possibly use the existing intake, and fab up everything else. Any pointers from those who use hairdryers would be appreciated. Also, I would like to know if the stock electronics and injectors would hold up ok keeping it mild, and what changes could I make without getting into tuning or going with another ecm. Thanks for the knowledge iv'e already received from you guys! Eric

11-20-2008, 05:43 PM
If you want to avoid tuning, you better just leave it stock. Thats going to be the most important part when its all completed. The stock injectors really arnt up to much, I'm pretty sure you can make more power with less injector when using a turbo instead of a sc, but I highly doubt the 30's are up to the task. Thats all I have, I know squat about turbos, try a search tho, A few guys have done it, but they wernt afraid to shoot for the 400rwhp mark, and they had planned on doing extensive tuning.

11-20-2008, 05:44 PM
Going with a turbo and being safe will require a tune, even if its only a mild turbo. The air flow characteristics of your car is going to change, and measuring airflow is probably the most important function in regards to determining how much fuel to deliver. The EEC (ECU) will be fine with the existing wiring etc you have in the car.

Out of curiosity, why do you want to avoid a tune?


11-20-2008, 05:53 PM
I would use two ity bitty turboes not one

11-20-2008, 06:19 PM
Not that I would avoid a tune, it just seems that the stock computers are fairly versatile. Is it possible, or have I read wrong, to put in bigger injectors with a matched maf without tuning? I am well aware that there is power freed up by using a turbo vs sc, so I guess I'm just wondering that as long as all aspects of monitoring act, maf, o2, etc remain the same, the power adder shouldn't make a difference (to a point).

11-20-2008, 06:20 PM
I would use two ity bitty turboes not one

That's not out of the realm of possibility, either.:D

11-20-2008, 06:32 PM
Because air flow is the most important piece to determine how much fuel gets delivered, and a simple thing like changing from the stock airbox to a custom intake with a cone filter can actually alter how the air gets metered, you can start to see where changing the air intake system to fit to a turbo will drastically change how the air flows so you'll need a tune.

Especially if you decide to go with a blow through setup which I don't really recommend doing with our stock MAF's and sensor's.

Honestly, it doesn't cost much these days for a chip-n-tune. As for injectors, if you don't plan on moving any more air than what the stock setup can do, then 30's would be ok. 42's would give a comfort factor though.


11-20-2008, 06:51 PM
My car is an auto, and I wasn't planning on pushing more than 15 lbs for a while, so I was wondering about draw thru maf without a blowoff. Like I said, its not radical, and I'm not gonna be jamming a 5 speed. Larger maf, injectors and a tune?

12-05-2008, 06:55 AM
well my sugestion would be a single turbo and draw thru the oem MAF. isnt the oem boost level for a sc 12psi. if so set up the wastegate for 12 psi. Since you would be drawing thru the maf youll want to recirculate the bov which will otherwise be known as a bypass. Just make sure you have a good foot of pipe between the turbo and maf. Angle the bypass outlet as close to the compressors inlet s oyou woulnt have turbulant readings to the maf when the system purges boost back into the inlet pipe. theres a few different options for the pcv system youll have to research on that. make sure the turbocharger has a good path for the oil return (strait down to the pan no dips) . You already have an intercooler so youd be set there.

super red91
12-05-2008, 10:06 AM
If you are serious about going turbo you should really ditch the stock sc manifold. What is the reason to use it other than its already on the car? If you do use it you will still have to fab up something to use as an upper intake and attach the tb to. If you are going to go through all this you should just bolt on a regular 3.8 lower and make an upper intake, either that or throw a stock 3.8 upper on top of that. This alone could pick up 25+ hp and isnt all that much work.

12-05-2008, 10:47 AM
Why not just keep the SC and put a turbo in front of it :eek:

super red91
12-05-2008, 11:48 AM
Why complicate things and put that restriction in the way? MM&FF have already done testing on this with a cobra, in the end it was better to just run the turbo by itself.

12-05-2008, 12:05 PM
any forced induction requires a tune period. and not to mention the timing changes because you have to run atleast 91 octane with boost. and turbos require alot more tuning then a supercharger because it works off of load rather then just stuffing air in. as well i think someone also said this, a turbo is MUCH easier on internals then a s/c, they create no extra load like a s/c on the crank. yes 42lbs would be a safe factor as well as getting a bigger maf since your going to have to tne the turbo anyways. and a larger TB never hurts. your going to need a custom exhaust sytem to. talk to v6sprout, hes doing a turbo fab up right now. i think for the header he just flipped it over and cut from there lol. and as to a turbo and a s/c that would be sweet! but thats ALOT of fabbing and that would require even more tuning....benefits would be interesting to see. ive alwas wondered what a mpx on a 4.3 with a 72mm turbo would be like...lol a FMIC would be a must there. oh and for a IC on the turbo system you could weld 2 stock ones together and mount that on the front, but might be easier to just by a FMIC (not the kit) and then fab up the rest. for an intake manifold you could strip out the rotors and remove the belt on the m90 and use that as the intake.

12-05-2008, 02:00 PM

You can't go wrong....
I'd drop the Maf system/SC for that thing in a heartbeat...
The gains you will get running 15PSI with a turbo will be excellent with a bigger IC. end .02.
Good Luck!

super red91
12-05-2008, 02:16 PM
I don't understand all this talk about "a turbo is so hard to tune", forget the megasquirt (or any other aftermarket computer) and stick with the stock ford eec and chip (unless your trying to make some rediculous amount of hp).

Mine literally fired right up on the first start after switching it to turbo. I drove the car to the dyno. Dave tuned it with little to no drama, and the car drives the same if not better than it did before. All this will a C&L draw thru, stock ford eec, and a chip.

Those of you who are getting to involved into this need to step back and think of what is really needed to make it work, and then realize its not as hard as your making it out to be.

12-05-2008, 02:29 PM
little to no tuning involved? how much did it cost you for dave to tune your car. turbos DO require more refined tuning. sure you can do a tune and make it work, but are you getting its full poential? are you sure? ive seen someone with a 347, 60mm single, went to a shop that a great rep, he made 498rwhp, he went to another shop and it costs a about 200 bucks more for him to do a tune and he gave him a shot (someone promised him he could get more power) the guy increased mpg and was running 543rwhp. this is not a simple s/c. how many instruments does your tuner guy use to gather info? that plays a factor to, especially the exhaust reader

super red91
12-05-2008, 02:56 PM
Maybe Dave will chime in...

440rwhp @ 15psi with stock bottom end, mild cam, and gasket matched heads (stock valves)...I would say I'm getting the most potential out of it.

As far as time on the dyno, it was almost comparable to the time my car spent on the dyno when it was supercharged.

All I'm saying is that there is no reason to get overly involed and concerned about the tuning. My setup is simple and can be easily duplicated with minimal tuning required.

Maybe Dave is just the man:D

12-05-2008, 02:59 PM
MS enables a person to do much of the tuning himself, why pay somebody else to do it?
If you have the bucks and are going to squeeze every tenth out of your car at the track, I can understand it, but most people are not going to be able to "drive to the dyno". That's a best case scenario...
I have seen free software and DIY cabling with the MS device and a cheap wideband do all the needed tuning for both foreign and domestic vehicles.
I'm not trying to hurt anybody here, but I also know that most people can't afford a lot of things and still want to learn and build their vehicles for many reasons...

12-05-2008, 03:06 PM
lol maybe dave is the man! but wow 440rwhp on stock internals? i thought the s/c was only good for 400rwhp

XR7 Dave
12-05-2008, 03:14 PM
Ryan, some people are just thick headed. :p

It has been long said around here that anything non OE is going to be hell to tune. I got the same run-around with the AR's with all sorts of insinuations that the twin screw caused tuning issues. Another tuner on SCCOA even made a big deal that "he could tune AR's too" some time ago. Let's get real folks. If you can't tune a turbo you need to put the laptop down and slowly back away from the car.

By the time you buy, install, and map an aftermarket EMS system you are going to be waayyyyyyy beyond the stock system in terms of money, time, and frustration invested. Perhaps some people would like everyone else to believe that tuning the OE system is difficult to do so that they can continue to bolster their business, I just don't know.

Regardless, the Ford EMS system is the easiest system in the world to tune. It has a few things and quirks that take some getting used to but compared to 80 cell fuel and spark tables, an MAF curve is eleventy billion times easier and faster to dial in.

Tuning a turbo system is in no way more difficult that tuning a supercharger setup. If "your" tuner is having issues then I suggest you find someone else or learn to do it yourself. There are inexpensive hardware and software solutions for tuning the SC and the best part is that you don't have to change any parts or re-wire anything.


The Mustang will require some tuning due to it's N/A program.

XR7 Dave
12-05-2008, 03:16 PM
lol maybe dave is the man! but wow 440rwhp on stock internals? i thought the s/c was only good for 400rwhp

Define what you mean by "s/c". We've made 475rwhp with a twin screw on the stock bottom end. Clearly a turbo would have made another 50rwhp under the same conditions. Gotta be careful though at that power level due to detonation. The stock connecting rods do not like detonation.

12-05-2008, 03:52 PM
wow well that makes me feel better then. i was worried if i take my motor to 400rwhp it (stock bottom end) was gonna break eventually. but now i just need a good tune

12-05-2008, 06:48 PM
A couple of guys here already turbocharged a SC using the oem fuel/engine managment and it ran fine. Get a wideband 02 liek the AEM Uego they can be ahd for 200-250$ so you cna keep your eye on the AF. if you have issue from there then you can get into tuing the ecu. turbochargers are load based which make them a little harder to tune but the issue will be in boost. igf you get into boost and it pings lift your foot and dont get into it again until you can figure out why its pinging. The SC has a managment system setup for forced induction so you cna creep by with no tuning just keep it draw thru with a bypass and set the wastegate for the oem pressure. LB for LB of boost you will still see more power fro mthe turbo since its not draging on the crank and fuel economy will go up when cruising around town since the turbo will just free spin there and is not a pumping loss/or parasitic drag.

XR7 Dave
12-05-2008, 06:54 PM
fuel economy will go up when cruising around town since the turbo will just free spin there and is not a pumping loss/or parasitic drag. Not really. The supercharger draws less than 1hp when not in boost.

12-06-2008, 12:52 AM
what psi is the stock bottom good up to?

super red91
12-06-2008, 11:06 AM
I dont think its a matter of psi, as you can run alot of boost and no timing or vice versa. Its a matter of detonation as stock pistons and rods wont take much abuse.

I know it will handle 30+psi for a split second...

12-06-2008, 12:52 PM
Glad to see you guys jump back in on this. I enjoy seeing the different sides and I'm certainly itching to tinker after my xr gets makeup on. Wish me luck, getting married at 5 this evening. I'll check in when I can!


super red91
12-06-2008, 01:25 PM
Glad to see you guys jump back in on this. I enjoy seeing the different sides and I'm certainly itching to tinker after my xr gets makeup on. Wish me luck, getting married at 5 this evening. I'll check in when I can!


Congratulations...only a true sc guy would take time on his wedding day to check the car forums haha

12-12-2008, 12:13 AM
I have a fairly extensive write-up on mine so maybe grab a snack if you want to read what all went into mine...far from stock set-up...most recent updates are towards the last few pages. hopefully give you an idea of what it all entails. with dyno numbers etc...