300bhp carb turbo
Discussion
I'm sure others can provide more information than I, but the bottom line is this:
Assuming you are starting with a Turbo Esprit, 300HP is (in my opinion achievable), but a rough guideline for upgrades would be:
It might be best to consider swapping to an electronic ignition and a fuel injection setup, especially if you are serious about the 300HP mark, as you begin to run additional boost, you will start running into issues with the carbs (mainly that you have to swap jets to tune the fuel delivery, among other problems).
I don't remember who said it, but by swapping to fuel injection, it it possible to make significant horsepower gains without increasing boost (I think 250HP is possible without touching the turbo).
Beyond that, you will need some kind of intercooling setup to cool the compressed air from the turbo. The best way to do this (based on the Esprit's mid-engine design) is to go with a liquid to air intercooler (i.e. "chargecooler"
.
From there you can begin to increase boost. With careful tuning and a lot of care (and a fair amount of money), you should be able to get 300HP out of the stock engine without any changes to the internals.
Assuming you are starting with a Turbo Esprit, 300HP is (in my opinion achievable), but a rough guideline for upgrades would be:
It might be best to consider swapping to an electronic ignition and a fuel injection setup, especially if you are serious about the 300HP mark, as you begin to run additional boost, you will start running into issues with the carbs (mainly that you have to swap jets to tune the fuel delivery, among other problems).
I don't remember who said it, but by swapping to fuel injection, it it possible to make significant horsepower gains without increasing boost (I think 250HP is possible without touching the turbo).
Beyond that, you will need some kind of intercooling setup to cool the compressed air from the turbo. The best way to do this (based on the Esprit's mid-engine design) is to go with a liquid to air intercooler (i.e. "chargecooler"
. From there you can begin to increase boost. With careful tuning and a lot of care (and a fair amount of money), you should be able to get 300HP out of the stock engine without any changes to the internals.
sheddy31 said:
my car is a 1989 stevens esprit turbo with renault box. so what kind of bhp can be had with out haveing to convert to injection but adding a chargecooler and is there any other mods that should be done to get more power.
The horsepower you can get with carbs is about the horsepower that you have. You can get a little more hp cheaply by going with the "green dot" cam pulley on your intake cam instead of the emissions-restricted blue dot pulley (you should have a green dot pulley on your auxiliary shaft already - just swap them), but it's not a huge increase. There are other basics like lower restriction exhaust and porting and polishing the head, but again, you won't get another 40% out of it.
The problem with getting more power out of a carburetted car is accurate fuel metering. This is particularly difficult with a turbocharged car, because if you get it wrong and go lean under boost, you will melt pistons and all manner of other bad things. Your car should have forged pistons and nikasil liners, which helps, but they are still no match for a lean fuel charge. Adding a chargecooler or a bigger turbo doesn't help any in that regard.
The ultimate in power production for the 4-cyl Lotus engine is the setup from the S4S. The version of the engine in those cars has different diameter valves (intake, as I recall). It also has the capability of getting to over 300hp safely with tweaks like larger injectors, higher capacity fuel pumps, and ECU reprogramming.
Mike
sheddy31 said:
what would i have to do to my carbed turbo esprit to get 300bhp can this be done with out any major engine work
You could get to 300 bhp, but the modifications would be extensive and expensive. It would start with a engine rebuild since the cast pistons would never survive.
Assuming for the moment you achieve the 300 bhp goal, the Citroen transmission won't take that much power for long. The solution would be to upgrade to the later Renault gearbox.
But the Renault doesn't support the inboard brakes or bolt up to the stock halfshafts. So you'll need to swap in the complete rear suspension system from the later cars
There's a trend here... see it?
If you really need that kind of horsepower, it would be cheaper, and you would end up with a better, complete design package, if you simply traded up to a S-Turbo with the GM engine management system. Stock with a plug-n-play chip, and presto... 300 bhp.
No matter what you do with your carb-Turbo, the pistons are your limiter. Even stock they won't last forever... they're going to fail, the only question is when. Up the boost and they will fail quicker.
If you're willing to live with that possibility and take what you can get for as long as it lasts, then the stock pistons can handle 8.5 psi with little loss of longevity. And they can live with 9.0 psi, but the clock is running faster now. 10 psi feels very good, but you're on borrowed time. Enjoy it for the moment. Don't go beyond 10 psi without making other serious upgrades inside the engine and to the carbs/ fuel system. Above 10 psi, the pistons aren't your only limiter.
If you're willing to invest in a rebuild, then go with forged 8.5:1 pistons, Zeus head with big intake valves, 104 intake cam, 104 MOP pulleys all around, 10 psi of boost and the Euro distributro advance curve. Top it off with a lightweight flyweel and replace the dump valve with a BOV.
The car will be much more lively than stock, but far from 300bhp-lively. Probably sub-250 bhp. But the transmission will live with that as long as you don't indulge in drop-the-clutch starts. Roll off the line, shift clean and have fun in the twisties. It will not (!) be a car for the Stop Light Grand Prix.
Not good enough? Then trade up.
Regards and good luck,
Tim Engel
>> Edited by Esprit2 on Wednesday 22 February 02:15
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