740 Turbo 250-280 HP

Hello everyone, I'm new to this forum so i will introduce myself first.

My name is Remie and I'm from The Netherlands. I'm recently the proud owner of a 740 (sedan) Turbo from 1986, imported from South-France. The car is in pretty good shape: recently painted, tectyl treatment, Lowered on modified diesel springs and best for last brand new Ocean MK18 rims. The full black leather interior is from a 940 or 960 (not sure).

The engine however.... needs some attention. Which i am willing to give. It's a B200ET running Motronic. The engine has run 280.000 km and still does his job, but she likes oil and runs rough idle.

The engine is tuned by the previous owner but unfortunately he didn't start at stage 0.
It has a 3 inch exhaust system, an other chip (don't know what kind of), dumpvalve and the boost is turned up a little. He claimed the car has about 225 hp, but i doubt that. It is fast though. Going sideways isn't that hard

I am looking to get about 250-280 hp out of the car. (Of course first i need to take te car to stage 0) I already did a lot of research on this forum and think I got a good view of the options. I am thinking of this:


- Turbo:
I want to change the standard 13c Turbo to a 15G or 16T. Is this plug-and-play and are these the best turbo's to go with? If not, which one is?

- Exhaust:
I already got a 3 inch exhaust system, so i think this will be fine.

- Air intake
Of course optimize it, but how?

- Chip:
I hope my chip is good enough for this power. The previous owner said it will be...
What do you guys think is the best chip?

- Camshaft
I now have the standard T cam. Couldn't really figure out on this forum which one will suits me the best. I think it's the V cam?

- Injectors
This is unknown territory for me, but i will need bigger ones. Which one will do the job?

- Intercooler
Do i need to change something? bigger one?

I also would like to keep the dumpvalve (i love the pssssh) and maybe add a boost controller.

Other questions:
- I know the <1990 B200 isn't the strongest redblock, but will it handle 250-280 hp?
- I probably also need to change the Tranmission. Which one will suit?

A lot of questions by this newbie, I hope you guys can give me some advice.

It feels like I'm forgetting things, but couldn't come up with more.

Turbo: Yes it will be good enough, but changing to a 1990 onwards manifold will benefit if it doesn't have one.
Gearbox: What is it now? if auto, accumulator mod should be able to handle it, if M46, replace with M90.
Injectors: 850/v70/s70 T5 injectors.
Air box isn't bad expect it's in the way. So if you don't mind it, cut open the front on it. If going for a different intercooler that isn't the d088 one, you will need to change to a pod filter to make the pipework fit.

Good luck, that's all I have time to advise on!

Turbo: The Mitsu's are stretched at this power level. And the T wheels suck! I would suggest a Garrett T04E 50 trim. If you're looking for good spool, something like a stg II or III wheel in a .48 ar hotside housing would be awesome.

Air Intake: 3" MAF/AMM. You can take your existing electronics and transplant them in a larger housing, but will require a little tuning. And plumb fresh air from outside of the engine bay.

Camshaft: As you are in Europe, check SAM? http://www.sambilmode.se/ Otherwise RSI Stage I/II or IPD turbo cam.

Injector: Since the car is already turbo, you'll need low-z (low impedance injectors). As for size, I would decide on a target power level then pick injectors that can support that at a 70% to 80% duty cycle. Look around on the net and you'll find calculators that can help you figure out which injector is needed for your power level.

Intercooler: A better one is a good idea. People have made some impressive numbers of the OE intercoolers, but it's not recommended.

VQ said:

Injectors: 850/v70/s70 T5 injectors.

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Are those injectors high impedance? If yes, rewire to remove the resistors.

High impedance injectors are more available and nowadays those newer Volvo ones offer much better spray patterns. Run them and delete the resistor pack

16t's have been dyno'd here at 268whp. That's at or over 300bhp. 15g has been dyno'd at over 240whp. So again, that works for your goals. Mitsu's are easier to use due to their bolt on to the manifolds. Get a 90+ manifold. Bolt on. go.

The elephant in the room is your head and rods. Can someone confirm the 86 is a 'economy' motor? Skinny rods, weak valve springs. These are an issue.

The 86 engines got skinny rods and I think smaller bearings, not sure. You can run some power through it but not sure how much till it blows. That goes for the B230, I don't know how different the B200 is other than displacement.

Chesh made 230whp (~260 crank?) on a Motronic B230ET:



His mod list:

B230ET block with 13mm rods, 1st overbore ET pistons
531 head, ported/polished with oversize 38mm exhaust and 46mm inlet valves (stock is 35/44)
Enem V16 Turbo Cam
Ported out -90 manifold with a standard 42/48 Garrett T3 turbo at 14 psi
BSR chip
3" exhaust

Your B200ET should have the 531 already so that's good. You sure it's a mitsu 13c on there?

If you upgrade the injectors remember that you will need to use a bigger AFM. I imagine the 'upscaling' ratio is similar to LH2.4, so a 3" AFM (available on some BMW's) would require 30% bigger injectors to get the fueling somewhat correct during cruise.

A better intercooler would be a wise move, as Motronic relies heavily on intake temperatures to dictate ignition timing.

atrokz said:

16t's have been dyno'd here at 268whp. That's at or over 300bhp. 15g has been dyno'd at over 240whp. So again, that works for your goals. Mitsu's are easier to use due to their bolt on to the manifolds. Get a 90+ manifold. Bolt on. go.

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Not trying to sound confrontational here. Just want to chat on this a bit.

If you give him 35hp from drive line loss, that's barely over 300hp. On top of that, it prolly had to be run right out to the edge of it's efficiency (if not over). The T wheels don't flow for crap compared to the G wheels. According to maps over at Stealth 316, a 16t is barely cranking out 7 CFM more then 15g. To put a point on the disparity between the two designs, a small 16g will outflow the 16t by better then 90 CFM! At that rate, and if one should insist on staying with Mitsu, find a T3 flanged TDO5 with an internal gate (they're out there) should there be a need to use the OE manifold. Then a whole world of well flowing wheels are available.

The 15g and 16t -> 19t wheels are enough to get there, but with a better turbo (TD05 or Garrett) , once can hit their goals using less boost, staying in a better part of the efficiency island (cooler charge) and less risk of surge. There will also be more room for updating the existing unit in the future.

If OTOH, something that's easy to find and bolt on is paramount, then by all means get a Mitsu 16t, 18t, or 19t. They're fun turbos and it's easy as crap to get 'em onto an existing setup.

Lastly, having a manifold machined flat should cost little. It's also prolly not difficult to find someone to do it as well. But if that's too difficult, why not just buy one of these?




BTDT with Mitsu's. Had great fun! An M cam with a TD04 hotside from a 13c and 15g cold side is a torque monster! Big fun!!!! But once you start to getting into the high 200 range, the TDO4's stop being that good of a choice. Just an easy choice.

Yup. Just saying his goals are within reach with what he listed. The 'easiest' way to 250 imo. Didn't know you could mate up 15 and 13gs. interesting. I've got a T25 on my car now, which needs to go.

Found this chart online: http://www.greddy.com/products/turbochargers/turbochargers-misc./filter:model:T517Z/

I think the 19t or 16g will be a good and safe choice. So to be sure: with a +90 manifold this wil fit?

About the head, the b200et came with a 530 (i believe). I thought the 530 was a solid head and is able to handle this power.

I dont know what gearbox i got but it is 4 gears and electronic 5 (overdrive). Changing it to the stronger m90 might be a problem?

atrokz said:

Didn't know you could mate up 15 and 13gs. interesting.

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Nah mang! It was a 13c. At the time, I had a complete flat flange TD04HL-15G, but I just didn't have the means to make it worth with my down pipe at the time. So I got the bright idea of pulling the shafts out of both and putting the 13c wheel and shaft through the 15g CHRA. Just bolted the 15g wheel back on, re-clocked it, the put it back into the 13c hotside housing. Viola! Definitely didn't help the top end but it had enough torque for some accidental hoonage from time to time.

atrokz said:

I've got a T25 on my car now, which needs to go.

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I hear ya! My wagon had a Turbonetics Super 60 on it until last night. Wasn't an entirely bad snail, but not better then what I had laying around that's going on now.

How different is the build that remiasaus is looking at to a similar one on a 96 B200FT? Correct me if I'm wrong but the FT should have thicker rods and possiably be a squirter block.