Has anyone boosted a 735i?

laughac · laughac's Garage

I'm a Porsche guy thinking of swapping my Infiniti daily driver for the right Bimmer.

Tomorrow I'm to test drive an '88 735i that I could pick up for around $3k. If I sell my '02 I35 for over $10k that would give me (guilt-free) funds for performance goodies and maintenance for several years. My questions are:

1. Is '88 735i a strong platform for a turbocharged daily driver that I can take to the track occasionally?
2. Are there plenty of suspension upgrades available for this car?
3. What other models should I consider instead/also?

Unfortunately I need an auto trans for my daily commute rather than dropping my cellphone every time I get a call like I do in my 911.

Thanks in advance.

kdanie · kdanie's Garage

BMW turbocharged the m30 3.5L engine in the earlier 7 series and called it the 745 so the parts are available to boost that engine. The m30 engine is very stout and takes boost easily. Can't say how the automatic trans will react to high hp.

I can't tell you about the suspension side but the 7 series seems pretty large for a track car.

ken

EuroShark · 02-01-2008, 06:37 PM

I'm thinking of using twin turbos on my 750. I have a spare motor so i'm really thinking about it.

actone · 03-31-2008, 04:46 PM

Hi,
Did you ever buy the 735i? Just curious. What happened?

onboost · 04-08-2008, 02:41 PM

Yeah, I'm curious too..

As stated, it's pretty easy to build-up a boosted car on the existing platform but the M30 motor responds well to head-work, cam, headers and a remapped ECU.

I'm a Porsche guy as well. However I've always used Bimmers for the daily knock-around and I have an 90 735i with mods.

Almost sold mine a couple of times as it's now sitting becuase I over heated it in traffic with a bad waterpump & thermostat.. smack me cause I knew better!

I'm about to put it back together as soon as assembly of the fresh head is completed. Luckily I was able to save everything except the head. So I picked-up a good used one, had it ported and polished, 5 angle valve job, along with any other need machine work and it should be ready to go within the next week or so.

Engine is a Racing Dynamics modified unit with thier valves (1mm larger), cam, stainless steel headers and larger diameter exhaust. Having injectors matched, and will add a larger throttle body along with some ignition upgrades.

Car is a 5 spd and the only driveline mod I've made was a new driveshaft, center support and guibo. Oh and I did swap the standard diff for a 3.91 LSD out of an M5 and added a short shift kit. I like both.

Suspension work for these car is tough. H&R, Dinan, and Ebach all have springs for these cars and Bilstien offers a choice of HD or Sport.

The catch for all of this on an 88 is production date as it splits.. some 88 were produced in late 87 and have struts that fit ?/87> and another number fits ?/88> Then I think they split again. This affects what spring or shock for what year strut. The easy fix is to move to the 90-93 struts and upper strut bushings etc.. find used.

If anyone is interested, I have a spare set of used Racing Dynamics springs for the E32 735.
I'll let them go for $150 + shipping

Gus540i · 04-08-2008, 08:46 PM

For about the same money you can pick up a V8 Bimmer, don't know what kind of gas mileage your looking for but if you are mechanically inclined Schrick makes some cams for this particular application so that on 6 pounds of supercharged boost you can achieve around 400 ponies on a reasonable budget, if gas mileage is a consideration then please do not contemplate this mod for your mpg will drop considerably

onboost · 04-09-2008, 03:29 AM

Its quite obvious that the "V8 Bimmer" is available for not much more. However, for a V8 in the 735 price range, fixing neglected maintenance items and high mileage are a big factor.

Then gas mileage, coupled with some of the other known maintenance issues, the lack of 5spd availability, and the fact that the RD car was relatively rare were my reasons for not using a 740 as a platform.