E9 "Restomod" Ideas

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NMD22

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Hi All,

This is my first post and thank you to all of you who contribute so much great information here.

My current "European road trip" car is a Datsun 240Z, which has provided me with a decade of great memories and thousands of miles around France, Scotland, Spain and Portugal etc.

It is time for a change and, to my eyes, the E9 continues to age increasingly well. Given I like to drive and use my classic, the priority is to have a car that is fun and reliable and able to cope with 3,000 mile trips in all conditions and roads. Concours leave me cold.

I am thinking of a LHD 3.0 CSi with a few subtle modifications to make it more useable. Initial thoughts are to include a 5 speed gearbox, poss BMW engine change for something around 300bhp and I imagine some brake and suspension upgrades. In terms of colours, I think the Inka Orange colour is fantastic and also love the Brick Red of Robert Downey's restomod.

There are a couple of cars currently on the market - a red one in the UK with an asking price of £62.5k and a black one that has been posted on this forum from Spain at around Euros 45,000.

I read a lot about E9 rust issues and am torn between buying the best I can afford, even if that means ruining the value by swapping engines etc, or buying a cheaper car and spending to make it just as I like (which is what I did with my 240Z). The body shop I currently use tells me to expect a good re-paint to cost in the region of £10,000, plus of course any rust repairs required.

Any thoughts would be much appreciated.

Thanks, Nick D
 
hello Nick,

if you want a very dependable road trip car, a CSi is a good option if you have a really good nearby mechanic that understands the ageing D-jet injection. the same is true if you have a carb version, but it it simpler. getting 300 hp in an e9 is probably only possible by putting the s38 in it. modifying a 3.5L - b34 / b35 engine is possible but reliability of that tweaked of an engine on the road might be a stretch. 240 to 250 hp is very doable using megasquirt injection with a good cam and a little work from a person with a good understanding of the engine. the 5 speed is a relatively easy swap - as long as you can find one ... but many e9's for sale have already done the swap. when you redo an engine, you want to change things that are easy to change such as starter, alternator, cooling, etc to increase reliability.

you are correct you need to be very careful with rust, but there are some cars that have already dealt with it and a small group that has never had any significant rust ... then there is the group that have the question of when the rust is going to present itself. i can assure you that it is far cheaper to spend more on a car and avoid major rework - it will always cost much more than you anticipate. i recommend that you read the Technical section and pay attention to the 'rust prone' section. https://e9coupe.com/forum/pages/rust-prone-areas/

oh, one last thing - make sure to have a professional pre-purchase inspection by somebody familiar with e9 coupes - best money you will ever spend
 
Good plan Nick.
LHD is a good idea, 5-speed OD transmission is a must I think, CSi or equivalent makes sense for drivability perhaps, but I hear that 300 BHP is too much power for the car.
Suspension tweaks also make sense. I installed the sport Bilsteins and I am happy. Shorter springs would also be welcome but I have no experience. I installed sway bars and measured a 3x smaller body roll. I posted results in a thread.
In short, great plan, I would start soon before ICE and human driven cars are outlawed :).
 
"£10,000,"

I would double that estimate to include the rust repairs.

Good luck! Not sure 300hp is really necessary, but if it is, perhaps an M30B35 with a turbo can do it. S38s are $$$
 
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the amount of work you would have to do to the 50 year old body to withstand 300 hp is not to be danced around lightly. the differential / mount is going to have issues. the already flexible body is going to have issues. complete agree with Rob that S38s are extremely expensive these days. probably less expensive than trying to stuff the S54 into the coupe
 
rsporsche said:
hello Nick,

if you want a very dependable road trip car, a CSi is a good option if you have a really good nearby mechanic that understands the ageing D-jet injection. the same is true if you have a carb version, but it it simpler. getting 300 hp in an e9 is probably only possible by putting the s38 in it. modifying a 3.5L - b34 / b35 engine is possible but reliability of that tweaked of an engine on the road might be a stretch. 240 to 250 hp is very doable using megasquirt injection with a good cam and a little work from a person with a good understanding of the engine. the 5 speed is a relatively easy swap - as long as you can find one ... but many e9's for sale have already done the swap. when you redo an engine, you want to change things that are easy to change such as starter, alternator, cooling, etc to increase reliability.

you are correct you need to be very careful with rust, but there are some cars that have already dealt with it and a small group that has never had any significant rust ... then there is the group that have the question of when the rust is going to present itself. i can assure you that it is far cheaper to spend more on a car and avoid major rework - it will always cost much more than you anticipate. i recommend that you read the Technical section and pay attention to the 'rust prone' section. https://e9coupe.com/forum/pages/rust-prone-areas/

oh, one last thing - make sure to have a professional pre-purchase inspection by somebody familiar with e9 coupes - best money you will ever spend
Click to expand...

Hi,

Thank you for your detailed reply - much appreciated. The 300bhp need isn't fixed in stone, it is more about being able to keep up with the other reprobates on said trips. I personally prefer carbs to injection and had also thought about a 3.0 CS but given your comments about 240 bhp being doable by tweaking a CSi engine, that sounds like it could be a good plan.

All the best, Nick D
 
Arde said:
Good plan Nick.
LHD is a good idea, 5-speed OD transmission is a must I think, CSi or equivalent makes sense for drivability perhaps, but I hear that 300 BHP is too much power for the car.
Suspension tweaks also make sense. I installed the sport Bilsteins and I am happy. Shorter springs would also be welcome but I have no experience. I installed sway bars and measured a 3x smaller body roll. I posted results in a thread.
In short, great plan, I would start soon before ICE and human driven cars are outlawed :).
Click to expand...

Thanks Arde for your comments and suggestions. And yes, this needs to be done before our London Mayor has his way and bans all private cars!
 
teahead said:
"£10,000,"

I would double that estimate to include the rust repairs.

Good luck! Not sure 300hp is really unnecessary, but if it is, perhaps an M30B35 with a turbo can do it. S38s are $$$
Click to expand...

Thanks Rob,

My 240Z journey taught me to usually double an estimate so I suspect you are right!

It is sounding like enhancing a stock CSi engine and then fitting a 5 speed box may be the way to go.
 
NMD22 said:
Hi,

Thank you for your detailed reply - much appreciated. The 300bhp need isn't fixed in stone, it is more about being able to keep up with the other reprobates on said trips. I personally prefer carbs to injection and had also thought about a 3.0 CS but given your comments about 240 bhp being doable by tweaking a CSi engine, that sounds like it could be a good plan.

All the best, Nick D
Click to expand...
don't think i said that you could get 240 from tweaking a CSi engine, as i have no experience with that engine ... i said by using a 3.5L b34, b35 or m90 engine (the b34 has 10:1 compression, b35 i think has 9.3 but a better head), but that is dependent on the fuel injection. what we have learned from our friend @sfdon is that you can get 245 hp with megasquirt, a schrick 284 cam and some smart engine work such as porting the head. with the stock motronic injection on a b34 / b35 / m90 ... which all had somewhere between 205 / 215 hp originally - a better cam helps, as does some other head work, but that might only get you to 225 to 230. 240 was an approx. avg. for a 3.5L between megasquirt and motronic depending on what else was done.

what i did say about the stock CSi is that you have to have a good service option that is really good with D-jetronic injection. our friend @adawil2002 travels all over the USA in his beautiful CSi, but he has great nearby service.
 
Mortals can’t get 240hp out of a CSI motor, certainly not with d-jet. Even Alpina during the period continued to use carbs for their 230-250hp motors.

If you want any power over 200hp, your best bet is to find a 3.0CS and swap the motor. Although dyno sheets are sparse, It is regularly stated that you can get a B35 up to 240hp. Keep in mind that most e9 owners also have some type of 300hp+ modern euro, and those with a modded B35 all seem to be publicly elated with the power and road manners.

Disclaimer, this is all just bar napkin stuff for me. Not of it is applied experience. Maybe @wkohler can chime in with some real world experience.

If it truly is a restomod and you want 300+ hp, a custom turbo is probably the path of least resistance. You see very few turbo e9’s, but there is a boat load of room in the bay to fit all the plumbing you need. In the US, low compression B34 is an obvious choice. In Europe, I believe that the B35 is the same compression as the US at about 9:1. I’m not sure if you can get a thicker gasket to bring that down without getting custom pistons. The euro B34 has 10:1 compression with piano top pistons so not the best out-of-box choice. The lowest non-custom compression you could achieve would be US B34 pistons in a B35 long block, or US B34 pistons in a euro B34 with a B35 head. I’m *guessing that would bring you down to 7:1 but would love for someone who knows that they are talking about (hint hint) to confirm. The B35 head is the superior M30 head from an airflow perspective.

I would say that 80% of e9 owners and fans feel negatively about turbo e9’s for one reason (too much power) or another (period correctness).

Alternatively, an M88/3 motor fits without drivetrain/suspension modifications, and even in factory form you are looking at 280hp. If you can find an s38b36 or s38b38, you are now over 300hp. From a market standpoint, an m88/s38 e9 will sell with far less negative banter than say, a turbo b34/b35. Also, I think any M88/S38 variant would be a nice option for long distance highway driving.
 
rsporsche said:
don't think i said that you could get 240 from tweaking a CSi engine, as i have no experience with that engine ... i said by using a 3.5L b34, b35 or m90 engine (the b34 has 10:1 compression, b35 i think has 9.3 but a better head), but that is dependent on the fuel injection. what we have learned from our friend @sfdon is that you can get 245 hp with megasquirt, a schrick 284 cam and some smart engine work such as porting the head. with the stock motronic injection on a b34 / b35 / m90 ... which all had somewhere between 205 / 215 hp originally - a better cam helps, as does some other head work, but that might only get you to 225 to 230. 240 was an approx. avg. for a 3.5L between megasquirt and motronic depending on what else was done.

what i did say about the stock CSi is that you have to have a good service option that is really good with D-jetronic injection. our friend @adawil2002 travels all over the USA in his beautiful CSi, but he has great nearby service.
Click to expand...

My mistake Scott,

I got overly delusional / enthusiastic and suffered from selective reading!

Luckily there are a couple of highly recommended E9 engine specialists not too far away. That said, and call me old fashioned, I really do like carburettors...
 
Markos said:
Mortals can’t get 240hp out of a CSI motor, certainly not with d-jet. Even Alpina during the period continued to use carbs for their 230-250hp motors.

If you want any power over 200hp, your best bet is to find a 3.0CS and swap the motor. Although dyno sheets are sparse, It is regularly stated that you can get a B35 up to 240hp. Keep in mind that most e9 owners also have some type of 300hp+ modern euro, and those with a modded B35 all seem to be publicly elated with the power and road manners.

Disclaimer, this is all just bar napkin stuff for me. Not of it is applied experience. Maybe @wkohler can chime in with some real world experience.

If it truly is a restomod and you want 300+ hp, a custom turbo is probably the path of least resistance. You see very few turbo e9’s, but there is a boat load of room in the bay to fit all the plumbing you need. In the US, low compression B34 is an obvious choice. In Europe, I believe that the B35 is the same compression as the US at about 9:1. I’m not sure if you can get a thicker gasket to bring that down without getting custom pistons. The euro B34 has 10:1 compression with piano top pistons so not the best out-of-box choice. The lowest non-custom compression you could achieve would be US B34 pistons in a B35 long block, or US B34 pistons in a euro B34 with a B35 head. I’m *guessing that would bring you down to 7:1 but would love for someone who knows that they are talking about (hint hint) to confirm. The B35 head is the superior M30 head from an airflow perspective.

I would say that 80% of e9 owners and fans feel negatively about turbo e9’s for one reason (too much power) or another (period correctness).

Alternatively, an M88/3 motor fits without drivetrain/suspension modifications, and even in factory form you are looking at 280hp. If you can find an s38b36 or s38b38, you are now over 300hp. From a market standpoint, an m88/s38 e9 will sell with far less negative banter than say, a turbo b34/b35. Also, I think any M88/S38 variant would be a nice option for long distance highway driving.
Click to expand...

Many thanks Markos,

Personal preference would keep me away from a turbo and restomod is, perhaps, the wrong term in my case. I'd just like a bit more power, better suspension and better brakes than standard.
 
Hello Nick and welcome to the 'Twilight Zone'/Pandora's Box/Black Hole/Bottomless Pit of how one could build a 'hotter' E9.

All the members' previous post make excellent and valid points. Everyone will have their preferences on their secret ingredients and special sauces.

I built something along the lines of your idea for an 'enhanced touring and sport' E9 and have been living with it for 20+ years/100K KMs now. I am currently breaking in a pro built/re-built, hot M30B34 now and I'll share some thoughts :

1) How many people really will be traveling in the car on extended trips? Will I use the back seat for 'tiny' people or would I prefer/enjoy increased the cargo space 'in-the cab' and in reach? I did a rear seat delete (it is trimmed nicely) and it has been fantastic for long road trips and sport days. The delete saves on interior 'wear and tear' stresses, weight and $$ not upholstering the rear pcs.

2) Motor and color swapping? Then you basically can use any E9 shell you want....doesn't have to be 'CSi'... Body and Interiors are all basically the same.

3) Carb's or FI? Personal preference I think. There are pro's and con's to both. What do you want to see under the hood? I've wanted triples since my teen yrs in my dad's TR6, now I have them in the E9. ;) Any carb issues at altitude? I have not noticed any and I now live at 2500ft. Recently went up to 8000ft in the Sierra's and car ran great.

4) Brakes? The stock discs with braided lines and high temp fluid work fantastic. My car also does track days/HPDEs and I have never had any brake fade or stopping issues.

5) Suspension? Stock, these cars are floaty boats making them very nice long cruisers. Compared to your Z (sports car), the E9 is a heavier GT (Gran Tourer). If a crisper experience is desired, first consider beefier springs/shocks/sway bars. Want even more? Then do a HPDE/track day first and learn about what ya have. Then comes the why and how. Swapping all the suspension bushings for poly's and some coil-overs transforms it (and you?) over to the 'dark side'...at a potential cost of long touring comfort.

6) Modern electrics? If you are going to build a continental cruiser/barn stormer, then budget for some electrical repair/updating. I put in a new/modern aftermarket wiring harness. With my new triple set up, I added the 123 bluetooth dizzy that addresses many things. Similarly, the FI guys can dial/tune on their laptops.

7) Put in a AFR gauge. Somewhere.

In short, keep an open mind and find the best E9 shell possible. From there determine which camp your joining (FI or Carbs) and enter the rabbit hole.

This forum has been invaluable in my project's 'journey'.... lotsa good folk here willing to help and share.

HTH, good luck and have fun with it!
 
I live in California and frequently drive my 2800cs. I have no issues keeping up with traffic with the 2.8l engine/5-speed. I have also had the bored and stroked m90 with big cam, big headers, and megasquirt fuel injection. I would say the best bang for your pound is to source a b35 including the fuel injection system and wiring harness and build a nice 3.5l for you e9. with a mild cam and a chip you'll be close to a reliable 225hp give or take and you'll easily be able to keep up with traffic. The beautiful thing about this formula is that it is a tried and proven installation, is extremely reliable (I know, I've said this twice), and any BMW independent shop can diagnose and work on it. Horsepower gets expensive if you want more, especially if you build a custom engine. You can easily spend $15,000.00 just for the engine and that doesn't include installing and tuning.

As mentioned by others, the e9 chassis just isn't robust enough to handle extra hp. The best chassis to start with is usually and automatic since they didn't get as much abuse. The automatic transmissions really don't allow for flogging thus less chassis fatigue.

Ultimately, reliable is more fun. Fuel injection is less tuning and fiddling especially when climbing up the Italian Alps.
 
OCCoupe said:
... I have also had the bored and stroked m90 with big cam, big headers, and megasquirt fuel injection. I would say the best bang for your pound is to source a b35 including the fuel injection system and wiring harness and build a nice 3.5l for you e9. with a mild cam and a chip you'll be close to a reliable 225hp give or take and you'll easily be able to keep up with traffic.
Click to expand...
Mike, can you compare for us the B35 vs. M90?
Is my admiration for the M90 just nostalgic?
 
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