[Mk2] [Turbo] Costs of 500hp

[SpamDubz]

So the rings in cylinder 4 on my Rev 2 tubby decided to let go on Saturday. The original plan for my car was to eventually build it for 500hp, looks like it's coming round sooner than expected.

I wanted to get some kind of idea on what it's going to cost me to get 500hp reliably. I will use the car mainly on the road at weekends. Possibly a few trackdays if I get bored of taking the mx5 round. I'm not 100% set on how I'm going to achieve the 500hp, I don't mind swapping different engines or blocks etc. It just needs to be reliable and drivable on the road.

My maximum budget is going to be £5000. I would like to use less if I can without making too many compromises. Am I going to be expecting to spend way less? Way more?

I forgot to mention, I'll be building it myself, the only thing I can't do myself is the machine work due to not having the equipment. So labour costs aren't included.

Thanks in advance,

Dan.

[markstevieandmads]

Why 500bhp?

I've heard 320-350bho is the sweet spot for these cars and that would be alot easier.

[SpamDubz]

Mine was running 300 when it died and I admit it was a lot of fun. I just feel like I need more, I have a daily for work and back so it'll be nice to have an animal as a toy.

[gnzyza]

I know what you mean. You get used to the power quickly and it's addictive too

With the mr2 , it's not the type of car you can just throw around so I totally get it why people go for high power builds.

I'm sure someone will be along to advise.

I do think 400bhp is easier to achieve. 500 would be pretty much the same route save a few more parts but will need to be more though out in terms of what parts you choose and how they will work together.

[kev8611]

£5k wont see you far to be honest. Near half of that will be taken by a good turbo kit. £2k

Fuelling will be injectors, rail, pump, pressure regulator and lines etc then an ecu to control them budget another 1500 atleast for that.

Engine build. Pistons will be 500. All gaskets and arp studs. Water pump. Oil pump belt kit etc will eat rest of your budget. Add cams to that list too

Then you still need to factor in how your getting power down. Inner cv's, clutch. Good brakes to stop the thing as well.

An intercooler setup too will be needed.

Then theres other small things that are often forgotten about. Boost controller, wideband etc

I would say £8k is more realistic and even then maybe add to that

[kev8611]

400bhp in one of these is a very quick car. And is probably a bit easier to achieve as certain components wont be as much at their capacity as the would at 500.

Good on you for wanting to build it yourself though, take your time and follow every step carefully, get your head in a book and work off a list without cutting corners.

I built mine and would do it again in a heartbeat

Go for it!!

[SpamDubz]

Thanks for the replies so far, I currently already have a standalone Ecu sat around gathering dust, boost controller, intercooler and/or charge cooler set ups laying around, brakes are upgraded already. That could cut out a good chunk of the price. Also I'm not shy about getting second hand parts if they are decent and right for the build.

I've never done a full forged build myself before so it's pretty exciting to say the least. I think I'd be happy with 400-450 but 500 is going to be my goal. Weather I reach it with the budget or not is a different question. I'm sure as hell going to give it my best!

I'm not decided on what turbo to go for as of yet. I was hoping a gt35 or similar would be a good start. I'd like something a bit smaller for better spool but I don't think id make the power I want with anything smaller than a 35, although I'm not too clued up on turbos at the minute. I'm thinking about running water/meth at higher boost levels to keep knock away, and potentially allow me to go for a smaller turbo??

Cheers,

Dan.

[kev8611]

A gt3076 will make that power with decent intercooling.

[GTMatt]

I have my car currently running just over 400hp and without looking at my receipts £8K could get you somewhere close to buying all the bits some second hand parts probably (which then runs the risk of them being duff and buying twice essentially). I bought pretty much everything brand new and £8k wouldn't have covered the component costs, let alone labour costs for engine builder/ mapper etc.
I looked into this whole idea of 400hp before I started years ago and people were providing estimate figures and honestly if someone had shown me the true bill I have ended up with before I started I probably wouldn't have started at all.

Please don't let this put you off, and don't get me wrong I now love my car, but in my experience it was a long old road which cost far more than I would have imagined. So in summary be committed and potentially surprised by how much it could cost you to complete.

That's just my 10 pence worth and I'm sure people will agree/ disagree based on there own experiences.

[SpamDubz]

Cheers for the info GTMatt £8k doesn't put me of at all, it just increases the original time scale I set. I will be buying what I can new, then maybe some bit second hand. I won't get second hand Pistons, rods, turbo, etc. I think I could cut the cost down to around £6500 as I have some stuff already on my car and the only labour cost I will be paying for is tuning, the rest I'm doing myself.

I want to get myself a list going of parts I'm going to need/use. So far I've decided I want to go 9:1 wiesco pistons, boot mounted charge cooler, water/meth, gt3076, maybe even a gtx series of budget allows. Tial external waste gate. These are just my first thoughts.

Dan.

[ashley]

To be honest- you'll really struggle to see 500hp on a GT3076...in the GT series you'll be looking at the frankenstein GT3082, or jumping up to a GT3582.

If you go with a GTX series turbo (or HTA) then a 30 turbine housing will be more able to flow 500hp.

Not questioning your decision, but why have you decided you want 9:1 pistons already? Best bet would be to get the block and head ready, then decide what compression ratio you want to see whilst maintaining design spec squish, and then select pistons. You'll also know what diameter pistons you need at that stage as the state of your bores will be a know quantity.

Aim to build it without water-meth, then add that later (in my opinion of course!)...design the engine to run as you want without it, then anything you may/ may not get by adding it is a bonus.

Get a project/ members profile thread going- keen to see what you come up with

[rev3gtturbo]

With the mr2 , it's not the type of car you can just throw around ....

Why not? Should be able to throw it around quite nicely on roads with half decent tyres and shocks.

When I got my current car it was slower than the previous mr2 turbo cos the shocks/tyres meant it could not hold the same line around a corner which meant I had to go into corners much slower even on dry roads. It also meant I could not put the power down as early so it was also slower out of corners.

I could have spent loads increasing engine power thinking it would make it faster, but there was no point if my suspension/tyres wont let me use the power it already has. For me it was way cheaper to fit new shocks and tyres and I am happy with that.

One of the things I really like about the mr2 turbo is the way it holds a line on a bend/roundabout and on the power whilst other people are running wide and/or backing off. Yeah they can catch you on the straight if they exceed the speed limit, but for me the fun is in the cornering and also getting on the power early.

[gnzyza]

Don't know where my post went... Ok here goes again.

I don't disagree with you but holding a line around a bend is not the same as throwing it about. I don't think people go for 500 builds to compete in best handling, in fact if the car handled that well we would be getting more questions asking how power will upset the handling etc.

I was just replying to the guy who said 320-350 was the sweet spot, I would agree with him from handling pov. Just merely stating chasing big numbers people have other goals too.

[SpamDubz]

Ashley - Thanks for the info, this is the sort of stuff I need to know and I appreciate the input! I'm not completely set on 9:1 but I'd like to have a decent amount of power off boost as well as on boost. I've also seen a few builds that use 9:1 that look to be successful. If I'm honest I'd like to try a higher comp build but I haven't got the balls and that's when different fuels are going to be needed which I don't want for a road car. From what you're saying I'll aim for a GTX series. I'll get a project thread etc up and going once I've got some things to put on there don't worry !

Rev3gtturbo - I agree with you in a sense, I find my mr2 handles really well and I can throw is about to a certain degree without worry. It holds the rear straight surprisingly well despite all the horror stories. I don't think 500hp will kill the handling but it'll just require better/more careful throttle control on the corners.

Dan.

[ashley]

I understand wanting to preserve off-boost response by running a higher static CR, but if you do the maths- you really lose very little power by dropping 0.5:1...it's a surprise when you run the numbers!

Also- this then allows you to make FAR more power when on boost as you don't have to overly retard ignition- which is a big issue on the 3S engines. Other designs of engine can lap it up- but these just don't, and you end up with really high EGTs, a sign of an engine not running to it's full potential.

But that said- it's all up to you and whoever designs the engine with you, and exactly what you want it to do. If you want 500hp to say you have it, but then rarely drive it at that level- then yeah, a higher CR would be fine. If you want to drive it at peal boost levels on a sustained basis, then you are risking reliability issues with a higher CR.

You can build a 3S to run 2 bar of boost at 11:1 CR, but don't expect it to do it all day long...and you'll need to be using a far higher octane fuel than we get in the UK pumps.

All in my opinion, you'll get different stories from other members on here

[Odin_S]

I can put my input in here since my project is almost finished. £5000 will buy you parts, but then you don't factor in things that don't go as planned. For example in my case one of my piston rings came broken

Luckily my gift of the gab changed that without charge. It's all the hidden gaskets you don't factor into the cost. My engine rebuild cost 3k on its own. Then there's the mapping etc.

My final stage now is I'm fitting an Aquamist progressive water/meth kit, something i thought I'd never do. This cost a pretty penny as i want it controlled by the ECU. Hopefully all will be worth it for a "reliable" 400bhp

A thread to follow when complete. Just for reference for your build, here's mine.

Wosser 8.0:1cr pistons
Standard conrods
800cc sard
Link G4 ecu
Phoenix Power SMIC
Aquamist HFS3 WI kit
4 bar map sensor

Good luck matey, hope you have an understanding GF/Wife

[SpamDubz]

Ashley - from what you're saying, it's kind of tempting to go lower with compression as it'll make more power on boost, thus reaching my goal easier and cheaper. You're input you're input has been really useful so far, thank you! You say these engines don't respond well to ignition retarding. I've also been considering different engines to put in but I'm not sure weather there is an engine that is going to be beneficial enough and cost efficient. Any ideas?

Odin_s - Didn't expect the engine rebuild to be so costly to be honest but it isn't putting me off at all im going to ditch the side mount as it soaks heat too much for my liking. I want to get a real good inter cooling setup for mine, fairly large charge cooler with radiator at the front. Should help me with my power goal. Water/meth can be made a lot cheaper than the kits imo. Thanks for the input!

Dan

[ashley]

Depends how deep your pockets are! Toyota V6 conversions are popular, the 2GRFE being the Daddy when supercharged, but you'll pay for it.

Lot of US builds swapping in Honda K20's, which seem to respond really well to boost...looks a fairly straight forward conversion if you're happy fabricating and modifying.

If you stay Toyota 4 pot, then a popular build is the later 5SFE bottom end- 2.2l, and far stronger than the 3S bottom end- and you can mate the 3S head to it as well, so manifolds are easy to sort.

Lots of options...have a read through the Member's section (if you haven't already), and the US owners club forum for ideas

[SpamDubz]

I was thinking about a k20 turbo swap but I think it'd be a lot more expensive to do unless I boosted it without rebuilding it which I wouldn't feel confident doing. I think I'll look into the costing of a k20 turbo more, I've always like those engines.

I was also thinking of a 5s block but I've been looking for one for a long time and can't find them anywhere. If one turned up I'd probably grab it.

I can't imagine a v6 is going to be any easier to work on than a 4 pot in the mr2 bay unfortunately as much as I'd love it.

Dan.

[gnzyza]

Would love to see someone on here do a turbo'd K20 swap