Boost!?

[adrian1]

WOW !! that is some great work your doing to that N/a. I can't wait till its done keep us posted.

[bholmes]

Hopefully I'll get to see it through to completion. I haven't had time lately even to do even the basic maintanace on the car and it is getting quite frustrating. Thanks for the encouragement though! I will keep you posted!

[blown 944]

Sickwidit,

I feel your pain as to not be able to get back up.

I did get up to Bandimere for some base line runs last week and the results were definately not what I was looking for.

I didn't post them on renns as I was wanting to get a really good time first. It ended up raining after 2 runs and I couln't get it off the line right yet.

The best I could muster was a 13.82 @ 104 out of the 2 runs
the other run was a 14.40 something at 104

I had the boost set pretty low to get a feel for the car.

At least the MPH is OK

I didn't realize how much harder it was to launch the turbo car in comparison to the s/c car.

I am going to try to get back up either friday or wedsnday of next week and crank up the boost.

I can't wait until my lil mule is totally ready to get back up it will rock no doubt.

[bholmes]

Sid, What fpr and rrfpr did you use? What gauge and adaptors did you use? I know Lindsey racing offers a kit, but it's a little steep to me. I like the machined face gauge summit has.... Also how did you calculate the apropriate PSI for your injectors at idle or for me while not under boost?

[bholmes]

Oh yeah, how do I know what ratio of rrfpr I need? I know the vortec units from Jegs come in a variety of ratios.

[88BlueTSiQuest]

I'm not sure what boost level the 1G DSMs ran, but if you are going to keep it conservative, see if you can get a wastegate actuator from a Conquest or Starion, 88-89. They were a dual port(actually 3 port, but 2 ports were tied together) actuator, 1 port set to open at 7.5psi the other port set to ~10.5psi. Go to www.starquestclub.com for a good classifieds section.

As to the issue of boost creep, I was running 16psi on my Conquest(2.6l SOHC), and never saw any issues from the TD05-12a. However, there are larger wastegate flappers generally available on ebay, which would probably be a good mod to help controller boost spike and get a tighter hold on lower boost levels. I know my 12a could still hit 8psi with the wastegate wide open(flapper broke, and fell out of wastegate).

[bholmes]

I'm only looking to boost around 9psi I'd guess. Can you explain the dual port actuator to me? Does it start to open the waste gate at 7.5 psi and then open it further at 10.5 psi? If so I may be able to swing that. It all depends I think on how I do my ignition set up. If I have an ignition retard set up some how I think I can pull 10.5 or so PSI, with out it I think i'll be doing good to get 9psi. I've thought about mega squirt and I've thought about an after market retard set up that wires into the ignition and is actuated by boost. and I've thought about no retard at all....we'll see. Thanks for the info!

[blown 944]

Brian on the s/c car I have the stock FPR modified (crushed, pulled back many times )

I also have the Vortech RRFPR. If I were you (and I will be doing the same shortly) I would buy the kit for the vortech that has the different ratio springs. When I do my next change to the s/c car (lil mule) I will be installing larger injectors again and running either a 1:1 or 2:1 spring in it.

the turbo car has an adjustable FPR with a 1:1 built into it. Not sure of the brand. I just used a bike pump to see what the rate was.

If I were you I wouldn't worry so much about the overboost of the mitsu turbo as these heads flow pretty well and I bet it doesn't creep too much on you. For now I would even use the internal wastegate to simplify things a bit. You can always port the flapper opening to relieve the exaust to slow it down some.

[blown 944]

As for the gauge it is just some plumbing (brass) fittings with a viton oring and a std test gauge on the end of the rail.

[blown 944]

As for calculating the injector rate I used some info off of the rc injector site. Pretty much it was trial and error though. I just figured if I lowered the pressure in a relative amount to the size of injector that it would be good at idle and from there it is jsut fine tuning the mix off idle and as long as I didn't get carried away with the injector size it would be feasable.


Icey and Dally D can let you know how it is using larger injectors, even N/A, they have had them on for some time now. They both have the ford 36 # injectors on their cars at this oint w/o the superchargers on yet.

My next step is to go with some 55# injectors and a 1:1 and try to get about 18-20 psi out of the mule with my next round of mods should be fun.

[TibetanT]

Hello There:

I have got two (2) fuel injectors for sure from a 1986 951 Turbo and possibly a third. They were taken out of a car that had 10K miles on it.

Asking $60.00 plus $8.00 shipping.

[bholmes]

I thank ya for the offer, but the injectors from the 951 and the 944n/a are both low impedance, but they still register a difference in resistance (ohms) that is to great for the computor to be able to compensate for with out much work.

[blown 944]

It would be nice if they were the same but the 951's are around 5.5 and the na stuff uses 2.6-2.8 thankfully. That is a good deal if they are from a car that has 10k on it though. It's too bad they are not the 55# ones that's what I'm looking for now.

I can't figure out why Porsche would use such a strange resistance injector on the Turbo cars. At least you can use resistors to use the lower impedance ones.

[88BlueTSiQuest]

Originally Posted by bholmes

Can you explain the dual port actuator to me? Does it start to open the waste gate at 7.5 psi and then open it further at 10.5 psi?

The Conquest/Starion had a solenoid that was hooked up just like a standard boost controller. For a 5 speed car, boost was limited to just 7.5psi until the car hit 4krpms, then the solenoid would switch to the 10.5psi port so long as knock wasn't detected.

On an Auto, the 10.5psi port was used all the way to redline, unless there was knock then it would kick it down to the 7.5psi.

You can use the 7.5psi port, along with a bleeder style, or EBC, boost controller to achieve whatever boost levels you want. But you also have the ability to simply limit your boost to 7.5psi by supplying the port with unbled intake pressure.

I just think it would be a better wastegate actuator to use, as I do believe the 1G DSM was at 10.5-11psi, so to achieve your 9psi you want, use the 7.5psi actuator and a standard bleed style controller(like a Lindsey, or the Home Depot variety).

[bholmes]

Jack, that's exactly what I was thinking about with respect to the lower pressure and a bleed type boost controler. Thanks for the tip, it's some great knowledge and I'll probobly make use of.

[PhillysMostWntd]

this is a good thread, what are your plans as for tuning the car? fmu's are an unreliable fuel management, they raise stock fuel pressures to unsafe levels, you may have issues with leaks, etc.

why not get larger injectors, and tune on standalone program, not sure if you already have a dme chip, but you could try to get a hold of stock ignition and timing maps, burn them onto a chip, make a basemap for boost, and get onto a dyno for some fine tuning?

[bholmes]

there's a few routes to take if I make it that far. Unfortunately it looks as if my project is in jepordy. The 944 is my daily driver and it's been requiring alot of work lately so the wife is not fond of it at all. However, I have considered 1)larger injectors, adj. fuel pressure reg. to drop the pressure down when not under boost and then add an fmu to help when under boost, then either live with the stock timing or add an aftermarket retard box that works off of boost or 2)use a megasquirt stand-alone unit and tune it from scratch, again using larger injectors or 3)have a guy on the board build me a prom chip tailored to my turbo application, and then do some data logging and have the chip reburnt to hone it in better. 4) be forced to sell it and be sad.

glad you like the thread, I hope it doesn't become just another one of the "almost turboed" threads, but even if it does, it has alot of very useful information.

[PhillysMostWntd]

there is a grassroots tuning program, called "chrome" not sure if you've heard of it, its free (unless you want the pro version) but i believe you could use that program to tune the car, its got a fairly easy interface, only obstacle is finding stock timing and fuel maps to start off with. our cars use 28 pin chips correct?

and for the timing module, your talking about using like an MSD BTM or something right? although they are somewhat effective, you can only retard timing like 3 degrees for every 1 psi, im not sure if that would be enough to keep away any detonation

i really hope everything works out for you, if i wasn't in college right now i'd be spending money on bringing the 944 back up to shape so i could attempt to turbo it, but school is priority right now you know? maybe one day though

[bholmes]

Hahahah! school, yeah I know all about that. I'm taking night classes, working during the day, got two kids and am tryin to get into pharm school...and I own a 944...now where did those 24hours go? can't seem to keep track of them...

[bholmes]

is the "chrome" things a chip burner or programer or what? i don't know alot about this sorta stuff. I'm sure you could get some decent fuel and timing table from some of the mega squirt guys.