rx7learner

OK I have a blow through turbo setup that works good. I bought MSII and some bike ITBs because even though I'm close with the fueling aspects... it's not where it should be and was thinking of going FI.

Non the less I have a choice. I have an 87 BMW 325is in mint condition and Im thinking about pulling the wideband controller my i/c, my i/c piping, bov, boost guages, oil pressure guage and using MS on it with upgraded injectors and a few other goodies... It's a 4 seater and much more comfortable for the family.

Then selling my oil pedistal for the oil feed along with connectors, my ported TII turbo with widdened wastegate NO SMOKE AND NO SHAFT PLAY, my modded TII turbo exhaust mani made to fit a 12a, and my carb hat from Robert and custom 3" RB downpipe with WBO bung. The down pipe is custom made to bolt onto the turbo and onto an RB street strip exhaust no welding needed if you have a RB street strip exhaust.

I'm thinking at least 700$ for the stuff above.

Then Convert my 7 back to N/A with my sidedraft mikuni and the street strip pressure plate, new clutch and GSL SE fuel pump and oil cooler along with RB Street strip exhaust and cutom low profile tires and reinforced drive shaft.

I'm thinking at least 1500$ for the car with an extra street ported 12a with a cracked end plate and many extra's.

OR!!!!

Try to get the GSXR 1000 throttle bodies mounted to my side draft intake, get big injectors to feed it (1000cc) make a custom conector for my turbo charge pipe, Get GM temp and IAT sensors and retrofit them wire up the MSII fuel only and see whats up (locked dizzy as it currently is)

To much to consider... maybe i am missing some options... please dont respond with useless comments like just give it to me... I just hate to go through all of the stuff I need to for this BMW and find out I miss my 7 anyway but right now I have tooooo many cars acording to my wife and the value of the 7's just dont seem to be getting much better... I can still get em for dirt cheap down here... thats why selling the whole package as is would force me to loose some big bucks.

81WideMariah

iTrader: (8)

Getting 1000 cc injectors to behave well under part-throttle and idle conditions will be a huge PITA, that's why most FI 7's use staged injection. That's your best bet. Personally I'd rebuild the 7, there's really nothing that can compare to a turbo'd FB. Even if you sell it as you're intending, you're still going to be taking a bath.

How exactly did you crack the rear iron?

rx7learner

Leaning out. Hence the ms.

81WideMariah

iTrader: (8)

You have bigger issues if you're leaning out.... either your jetting is wrong or your pump isn't keeping up.

rx7learner

Using a GSL-SE pump and I even went so far as to drill out the largest mikuni jets sold... Might be easier (more tunable) with a weber but I rather go FI if I was going that route.

81WideMariah

iTrader: (8)

Weber or OER would definitely be able to offer more tune-ability ... FI is not the end all/be all mind you. I tune EFI systems all day long... trust me on this.

rx71king

iTrader: (6)

how is your fuel pump wire ....... like are you using a relay and running a nice size power wire.

coldy13

The -SE pump is barely enough for a stockport 12a with a nikki, it WILL run lean at full throttle in 5th gear. If it's a street car and you don't go over 100mph you won't notice it, but WOT in 5th gear it will not keep up. When I switched to a weber it got even worse and I saw the fuel pressure dropping at the top of 4th instead of 5th like it did with the nikki.

My opinion, keep the BMW stock for a daily driver/family car and keep working on the 7. It's what I'm doing, except I had to do a few "custom" things to the beamer after my sister T-boned someone with it

Directfreak

iTrader: (2)

Weber carbs will run lean on blow through applications. The Fuel bowls are two small. They are good for only one or two gears at WOT before going dry.

Holley carbs can get bowl extenders and have sufficient fuel, especially double pumpers.

You might improve your situation with a bigger fuel pump, but not much.
IF you have the opportunity to go Fuel Injection - then do it.

rx7learner

thanks directfreak.

I have an itb off of a suzuki bike that i plan on using. The bores are 2mm smaller than my mikunis but with no venturis i'm hoping for adequate flow.

Using 2 of these injectors
http://www.diyautotune.com/catalog/d...owz-p-280.html

What I'm scared about is the comments about needing staged injection. I dont get it because I see the tweakit kits and they only use a pair of injectors. This shouldnt be that far off than that. From what I understand there is now a blended ability with my version of MS to use MAP and TPS that helps any idling issues out.

Directfreak

iTrader: (2)

As per your link - two injectors would only support 170 CRANK HP. Not even WHEEL HP.

I really recommend you just go with a TWM throttle body with 4 injectors.
That way most of your setup stays the same - just swap the carb for the throttlebody.

rx7learner

I think 170 is for E85. it says 248 at the crank on gasoline which I'm guessing is where I would be.

It's charted at 43.5 psi but max is 72.5 psi giving a flow rating of 123 lb/hr

If I go TWM the cost would drive me to rather get a holset turbo and boost my e30.

Do you think 248 at the crank will do it?

This setup would be for my stock port 12a

Directfreak

iTrader: (2)

248 HP at the crank - for a Piston Engine. You can easily reduce that by 30% for a Rotary.
That's also at the (kind of high) limit of running 85% duty cycle.

With only two injectors - only takes one hiccup under boost to toast the whole setup.

For all the trouble of running boost - you're going to want at least 300 wheel HP. That's the point the car will go from 'Nice and swift' to 'Quick as F**K".

If you rather do the BMW - then do it. You're not going to get the results you want by saving money on a rotary, lol.

j9fd3s

iTrader: (3)

since a turbo needs to run richer than an NA, 248 is a high number. on a ROTARY you'd be lucky to do 225-230hp with only 2 injectors.

bumping the pressure, IF the pump supports it, would give you about 25 more hp.

i suggest 4 injectors.

i'd also skip turboing the E30, 15psi on that will be like 10psi on the rotary, PLUS its going to cost WAY more to do.

that ballast they call and engine takes lots of abuse, but a 2.5L engine just will never make a ton of power without tons of money.

81WideMariah

iTrader: (8)

The big issue that I run into all the time at work is the guys wanting to run 80's on there blown, street driven Mustangs....

It doesn't matter how you slice, big injectors have big min pulse-width values, and big min PW's equal lot's of fuel at idle and cruise. Not to mention if you increase the rail pressure, it get's even worse. Plus you just won;t have that kind of fuel delivery control on a mechanically regulated return style fuel system. Even with a rising rate regulator you're only going to see a 1:1 increase in fuel pressure per pound of boost. So, with a base pressure of 40 (average) and increasing 1:1 to 15 psi... you're still only going to have about 55 pounds of fuel pressure, and that's considering your pump(s) can keep up.

The numbers posted in the link aren't too far.. they were figure using a Brake Specific Fuel Consumption of .65, which is a common BSFC for turbo'd piston engines, Rotaries are closer to .60. So you could plug in that BSFC and figure out the numbers.

Long story short, DF is giving sound advice (as always), but I'm going to pretend not to hear him about the Weber float bowl, since I'm in the middle of putting one on my build, but rest assure I have a plan B, in case it doesn't live up to my expectations. 300 HP is where you want to be, and it's certainly achievable, but pinching a penny now will end up costing 2 or 3 pennies later.

And for God's sake PORT THAT THING! You're gonna have to tear it down anyways... might as well. Hell, bring it to me and I'll port it for cheap..

Directfreak

iTrader: (2)

81WideMariah

iTrader: (8)

^^^^^ thanks buddy..

rx7learner

Its the money that is the issue.

I've been pricing stuff though... I just swicthed my BMW from auto to manual and have a new clutch in it. I can patch in the MS into the BMW wiring harness pull my wide band, IC, piping, and bov, leaving me with the cost of 6 injectors, an HX35 or H1c turbo off a dodge truck (perfect fit) and a mani, downpipe and exhaust.... your right the bmw is going to cost me more than the TWM and injectors....

OK... was thinking... what about getting 2 bungs put into my intake mani and using the 2 on the TB.... or maybe 4 on the mani and still using the mikuni with a jury rigged tps....

Someone has to have alternatives to the $$$$$ for the TWM after alll this is the rx7club.