I've been reading this thread and one thing has not been said.

Even if you DID get to your magical 200bhp, how long would the engine last? Just because it not a turbo does not mean its exempt from the same laws as when you try to get more power from a turbo

I would have thought you would have needed forged pistons at the very least. As said the rev 3 is already highly tuned and you would have to throw alot of money at it.

Dare i say get a turbo? i had a rev 3 na for 2 years and love it. but once i get the right turbo there was no going back. Try it, you might like it

Mate i say go for it when i tuned my calibra all my mates said why cause it wont make the car any faster. which they where wrong , if you got one of the engines which came with 170bhp why can't he get 200 out of it i got 180 out of my calibra which was 150 , i did the cams ported the head i enlarge the tb put on a 4 in to 1 manifold and put on a better induction kit chipped the ecu , If you think you got the skill to do it then why not we come on this site cause we love the car and to get help if he wants to then go for it mate put up some pic's on how your getting on i would like to see it

I get mr.two's point - he wants a fast NA MR2. But what I don't understand is why he has chosen a seemingly arbitrary target figure which almost no one has ever managed to get from a 3S-GE without spending the sort of money that would just buy you a used Boxter-S.

What's wrong with the Rev3 NA 3S-GE engine's standard 168bhp? Is that not fast enough? Strip some weight from the car - fit carbon body panels and remove the carpets, that will make the car faster far more cost-effectively than trying to squeeze an already squeezed engine to push more horses.

I've read you can get supercharger kits for MX5s that'll put you up to 190 ish bhp, which given the standard sub 1000kg weight of a mk1 MX5 gives you more overal power than a 200bhp MR2 with no carpets Being front-mid it'll be slightly less tail-happy too. Oh, and they're DIRT cheap these days.

Mr Blue wrote:Mate i say go for it when i tuned my calibra all my mates said why cause it wont make the car any faster. which they where wrong , if you got one of the engines which came with 170bhp why can't he get 200 out of it i got 180 out of my calibra which was 150 , i did the cams ported the head i enlarge the tb put on a 4 in to 1 manifold and put on a better induction kit chipped the ecu...

The reason you can see gains like that on your calibra is because they're a pretty poor engine design in the first place, loads of room for improvement by porting the head, cams, etc. The toyota is already done relatively well from the factory, so there aren't as many gains to be had without spending thousands.

I went through this decision process a few years back -the threads / replies are on imoc though. Basically I wanted to get 200Bhp from an N/A and I really wasn't interested in V6 or Tubby swaps (still not). I went for a BEAMS swap in the end simply because it saved allot of work and was a very proven engine.

If I recall a rough list of mods for a rev 2 which might see close to 200Bhp at the fly would be:

Ported and polisted inlet and exhaust manifolds -ports over / undermatched to the head
Rev 3+ head or fettling the flow in the rev 2 one (some modding required to fit a later head)
Take the PCV line to a catch can with breather filter
Fettle the valve profiles etc
More agressive cams and vernier pulleys
New tb mount to suit a larger tb + a Nissan Pulsar throttle body was mentioned to me at the time Free flowing exhaust manifold
De-cat and sports exhaust
Wideband O2 set-up
Decent induction kit with free flowing filter
Standalone ECU

If you want to weigh that lot up with say the set-up in a BEAMS 4cyl engine then Toyota already tuned the inlet runners (there is no ACIS and there are four fixed length tuned inlet trumpets within the oval shaped plenum), larger throttle body, better exhaust manifold, high flowing head, some internal works to do with oil ways etc and they fitted VVT-i to cope with very aggressive cam profiles and the inlet rnners (I'm informed the cams are equivalent to 272deg profiles). The stock ECU can still be improved on though!

....if you wanted to add a quad throttle set-up rather than single tb:

Custom inlet manifold and remove ACIS
4 throttle bodies (plenty of choice I guess if you want to use 2nd hand parts) and TPS
Find some matching throttle trumpets and either run socks or a single "sausage filter"
Conversion to MAP if not done so before
Fit some form of IAT sensor in a suitable place
Lightweight flywheel
Uprated clutch

(don't be fooled into thinking a lightweight flywheel and uprated clutch will give more Bhp like you see stated in a few of the car magazines)

Toda Europe do a bolt on itb kit for the 3S engines BUT I've seen a copy kit with comments relating to poor quality machining and poor flow through the tb's. Their website seems to come up with an error at the moment so can't find the link.

Remember itb's won't see you much increase in bhp (if any) on a 3S engine like you might on others -they're there as a later mod to bring in all the breathening and any lightening mods you can do so that you have less restriction when upping the rev limit. They're not a standalone bolt on mod. If you're considering them there is also some calculations you can do or rules to follow to a) set the inlet length between the butterfly and the valve face b) the diameter of the throttle / trumpet base and c) the length of the trumpet to give you a guide to the power and torque characteristics.

It looks like there is enough room for itb's between the rear firewall and the back face of the block -well there is on mine anyway as I have an itb set-up waiting to go on mine. At the moment I'm running an 183Bhp (wheels) which for pub bragging rights is an estimated 219Bhp (Fly) from a mapping session on mine which is fitted with a SARD induction kit, de-cat and blue flame exhaust, C-One flywheel, Helix stage 1 clutch and a Link G3 XLEM ecu with Link Display and Innovate wideband O2 -I converted to MAP so I could go itb's next although I still use the horrid MAF torpeedo in the inlet to get an IAT. In fact during the mapping I did a back to back test of stock intake vs SARD induction kit and saw a genuine 8Bhp difference which was upped a bit following Lyndon tweeking the map on the Link. These are just bolt-on mods and no internal works in the block so we thought that dyno figure was an awesome result.

I'm not sure if this is of any help to you but lookign at other posts I really wouldn't discourage anyone for staying NA and tuning a 4cyl. You just need to be very careful about your bang for your buck -the bang part isn't about the power it's the way you want it delivered on the NA (for me anyway). Expecting 40Bhp increase just isn't going to happen without some serious thought. Also I really can't drive mine properly and I miss huge amounts of potential from driver error as I don't drive mine much apart from weekends so I'm always jumping into it fresh again. I'd also turn your head to wheels, brakes and suspension before you do anything else because the MR2 can be driven much harder with these done FIRST in my experience.

Lastly enjoy the MR2 for what it is, I got an ST205 GT4 for when I want something with more seats and 4WD, and a modified mk 1 Caddy pick-up which I restored this year as my daily drive (60mph max from that on a 4 speed box!). The MR2 is the one which instantly puts the smile on my face every time I get in it.

I hope I don't create more of a stir on here -this is just my experience over the past few years. I think I would say to anyone rather than speculating to find a decent dyno centre and get a dyno run done first, and at as many points through the install as you can if you're looking at doing it at stages.

mr.two wrote:Looking at the inlet manifold, when in two pieces the lower half that comes off the head, basically just four pipes with butterfly valves inn, that look's ideal for a throttle body conversion.

Just wondering has anyone else tried it and if so how they went about removing the exisiting butterfly valves from the inlet manifold, im hoping i can use my existing injectors and tps etc.... just fabricate basically the throttle body and blade in a seperate bolt on individual throttle dody, and i do understand it's not as simple as i make it sound.

Back on topic.

Someone else has done it. You fabrication idea is still far fetched and very 'Heath Robinson'.
This guy is using modified Hayabusa quads, a much better starting point.

http://www.mr2.com/forums/na-5s-fe-3s-g ... build.html

I think you need to contact this person to get the information you need.
Good luck.

love ITB's


Linky for kits
http://www.mmsport.com.au/Throttle_Bodi ... sories.php

and fitted to a celica

http://www.youtube.com/watch?v=m2NUBzYCK_A

Even if you dont get the 200bhp mark (seen 210bhp on my old ITB'd C20XE had a huge spec list though) it will sound awesome

RSTA wrote:It looks like there is enough room for itb's between the rear firewall and the back face of the block -well there is on mine anyway as I have an itb set-up waiting to go on mine. At the moment I'm running an 183Bhp (wheels) which for pub bragging rights is an estimated 219Bhp (Fly) from a mapping session on mine which is fitted with a SARD induction kit, de-cat and blue flame exhaust, C-One flywheel, Helix stage 1 clutch and a Link G3 XLEM ecu with Link Display and Innovate wideband O2 -I converted to MAP so I could go itb's next although I still use the horrid MAF torpeedo in the inlet to get an IAT. In fact during the mapping I did a back to back test of stock intake vs SARD induction kit and saw a genuine 8Bhp difference which was upped a bit following Lyndon tweeking the map on the Link. These are just bolt-on mods and no internal works in the block so we thought that dyno figure was an awesome result.

That is impressive, How much, how long and how driveable is it????

Am I right in thinking that on top of Exhaust,decat and induction the only other tweek you've made is the Link G3? Btw how much torque?

183 i think is very good nice one

sinjen wrote:
That is impressive, How much, how long and how driveable is it????

[/quote]

The same as any other mk2 NA with filter/exhaust. Just faster.

nikk1877 wrote:

sinjen wrote:
That is impressive, How much, how long and how driveable is it????

The same as any other mk2 NA with filter/exhaust. Just faster.[/quote]


Fair point I'll just plug the brain back in, what can i say it was a late night!

Thanks all, some intereting and helpfull information there, thank you.

The Fiberglass Engine Cover's a great shout thank you, i'll be getting myself one of those, i know carben fibre do doors and wings, anyone know where i might find a fiberglass boot?

When i say i wanted 200bhp well i worked it out and that's 166bhp per tonne based on the car weigheing 1200kg...which got me thinking say i get 170bhp from, ITB's, full S/S, E.C.U. I've got a rev3 so i'm thinking that's reasonable based on what people say, then loose 100 kg, that should give me 150bhp per tonne, which i think is acceptable.

Lastly as i say i've found everyones input very helpfull, thank you. Can you get an MR2 to weigh less than 1000kg?? and if i have my ITB's and full S/S, with them being bolt on's, if i decide to then in the future change to a beams will i be able to just bolt them on to the beam's engine??

mr.two wrote:Can you get an MR2 to weigh less than 1000kg??

A mk2? It has been done, but it requires some rather extreme measures, and I'm not entirely sure it's road legal once all the glass has been replaced with perspex!

yeh ive a mk2 t-bar, so could replace the roof glass, i've thought about the windows but with them being pillarless i don't really want to do that for security reasons......Oh well, i'll try my best, i will be having a go at the DIY ITB's and i'll post how i get on for alll interested but don't expect it for a while got other projects on the go aswell and unfortunatly the MR2 is the highest insurance so it's the one off the road

Here's some food for thought aswell, i'm making a formula super 1000cc rally car rules state no more than 150bhp, from a 1000cc i'm looking at a more realistic 90bhp, quad carbs and lots of head work(bigger inlet ports, bigger valves, maximum sized exhaust ports), cam(only 8v), full S/S etc..........the reason i'm even saying this is it's in a citroen AX, which weighs 620kg without me inn, that gives it if i reach my 90bhp tagret, 120bhp per tonne roughly.

As i said food for thought weight=power